{"id":89534,"date":"2026-08-03T08:08:50","date_gmt":"2026-08-03T00:08:50","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/89534.html"},"modified":"2026-08-03T08:08:50","modified_gmt":"2026-08-03T00:08:50","slug":"linux-%e5%bc%82%e6%ad%a5%e9%80%9a%e7%9f%a5%e6%9c%ba%e5%88%b6%ef%bc%88fasync-sigio%ef%bc%89%e7%ae%80%e6%9e%90","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/89534.html","title":{"rendered":"Linux \u5f02\u6b65\u901a\u77e5\u673a\u5236\uff08fasync \/ SIGIO\uff09\u7b80\u6790"},"content":{"rendered":"<h2>Linux \u5f02\u6b65\u901a\u77e5\u673a\u5236&#xff08;fasync \/ SIGIO&#xff09;\u7b80\u6790<\/h2>\n<p>\u9002\u7528\u5185\u6838\u7248\u672c&#xff1a;2.6.x ~ 6.x<\/p>\n<hr \/>\n<h3>\u76ee\u5f55<\/h3>\n<ul>\n<li>\u7b2c 1 \u7ae0 \u5f02\u6b65\u901a\u77e5\u673a\u5236\u6982\u8ff0<\/li>\n<li>\u7b2c 2 \u7ae0 \u5e94\u7528\u5c42\u89c6\u89d2&#xff1a;\u5982\u4f55\u63a5\u6536\u5f02\u6b65\u901a\u77e5<\/li>\n<li>\u7b2c 3 \u7ae0 \u9a71\u52a8\u5c42\u89c6\u89d2&#xff1a;\u5982\u4f55\u53d1\u9001\u5f02\u6b65\u901a\u77e5<\/li>\n<li>\u7b2c 4 \u7ae0 \u5185\u6838\u7248\u672c\u6f14\u8fdb&#xff1a;\u4ece Device Tree \u5230 6.x<\/li>\n<li>\u7b2c 5 \u7ae0 \u673a\u5236\u6df1\u5165\u89e3\u6790<\/li>\n<li>\u7b2c 6 \u7ae0 \u6700\u4f73\u5b9e\u8df5\u4e0e\u5e38\u89c1\u95ee\u9898<\/li>\n<\/ul>\n<hr \/>\n<h3>\u7b2c 1 \u7ae0 \u5f02\u6b65\u901a\u77e5\u673a\u5236\u6982\u8ff0<\/h3>\n<h4>1.1 \u4ec0\u4e48\u662f\u5f02\u6b65\u901a\u77e5<\/h4>\n<p>Linux \u5f02\u6b65\u901a\u77e5&#xff08;Asynchronous Notification&#xff09;&#xff0c;\u53c8\u79f0 Signal-Driven I\/O&#xff0c;\u662f\u4e00\u79cd\u8ba9\u5185\u6838\u5728\u8bbe\u5907\u72b6\u6001\u53d8\u5316\u65f6\u4e3b\u52a8\u901a\u77e5\u7528\u6237\u8fdb\u7a0b\u7684\u673a\u5236\u3002\u5176\u6838\u5fc3\u601d\u60f3\u662f&#xff1a;<\/p>\n<p>\u5c06\u786c\u4ef6\u4e2d\u65ad\u7684\u54cd\u5e94\u6a21\u578b\u6620\u5c04\u5230\u7528\u6237\u7a7a\u95f4\u8fdb\u7a0b\u5c42\u9762\u2014\u2014\u5f53\u5916\u8bbe\u4ea7\u751f\u4e8b\u4ef6&#xff08;\u5982\u6309\u952e\u6309\u4e0b\u3001\u6570\u636e\u5230\u8fbe\u3001DMA \u5b8c\u6210&#xff09;\u65f6&#xff0c;\u9a71\u52a8\u7a0b\u5e8f\u4e0d\u7b49\u5f85\u7528\u6237\u8f6e\u8be2&#xff0c;\u800c\u662f\u4e3b\u52a8\u5411\u6ce8\u518c\u4e86\u5f02\u6b65\u901a\u77e5\u7684\u8fdb\u7a0b\u53d1\u9001 SIGIO \u4fe1\u53f7\u3002<\/p>\n<p>\u8be5\u673a\u5236\u89c4\u907f\u4e86\u8f6e\u8be2\u7684 CPU \u6d6a\u8d39&#xff0c;\u4e5f\u907f\u514d\u4e86\u963b\u585e I\/O \u5bfc\u81f4\u7684\u8fdb\u7a0b\u6302\u8d77&#xff0c;\u590d\u7528\u4e86 Linux \u6210\u719f\u7684\u4fe1\u53f7\u57fa\u7840\u8bbe\u65bd&#xff0c;\u4f53\u73b0\u4e86\u5185\u6838\u8bbe\u8ba1\u7684\u6a21\u5757\u5316\u4e0e\u590d\u7528\u6027\u539f\u5219\u3002<\/p>\n<h4>1.2 \u5f02\u6b65\u901a\u77e5 vs \u5f02\u6b65 I\/O vs \u963b\u585e\/\u975e\u963b\u585e I\/O<\/h4>\n<table>\n<tr>\u7279\u6027\u7ef4\u5ea6\u5f02\u6b65\u901a\u77e5 (fasync)POSIX \u5f02\u6b65 I\/O (AIO)\u963b\u585e\/\u975e\u963b\u585e I\/O<\/tr>\n<tbody>\n<tr>\n<td>\u89e6\u53d1\u4e3b\u4f53<\/td>\n<td>\u9a71\u52a8\u5728\u8d44\u6e90\u5c31\u7eea\u65f6\u4e3b\u52a8\u53d1\u8d77<\/td>\n<td>\u5e94\u7528\u4e3b\u52a8\u53d1\u8d77 I\/O \u8bf7\u6c42<\/td>\n<td>\u5e94\u7528\u4e3b\u52a8\u53d1\u8d77\u8bfb\u5199<\/td>\n<\/tr>\n<tr>\n<td>\u6838\u5fc3\u673a\u5236<\/td>\n<td>\u4fe1\u53f7 (SIGIO)<\/td>\n<td>io_submit() \/ io_getevents()<\/td>\n<td>read() \/ write()<\/td>\n<\/tr>\n<tr>\n<td>\u56de\u8c03\u6267\u884c<\/td>\n<td>\u7528\u6237\u7a7a\u95f4\u4fe1\u53f7\u5904\u7406\u51fd\u6570<\/td>\n<td>\u5185\u6838\u5b8c\u6210 I\/O \u540e\u8fd4\u56de\u7ed3\u679c<\/td>\n<td>\u65e0\u56de\u8c03&#xff0c;\u76f4\u63a5\u8fd4\u56de<\/td>\n<\/tr>\n<tr>\n<td>\u8d44\u6e90\u8bbf\u95ee<\/td>\n<td>\u4ec5\u901a\u77e5&#034;\u8d44\u6e90\u53ef\u7528&#034;&#xff0c;\u540e\u7eed\u4ecd\u9700\u663e\u5f0f read()\/write()<\/td>\n<td>\u5185\u6838\u81ea\u52a8\u5b8c\u6210\u6570\u636e\u642c\u8fd0<\/td>\n<td>\u5e94\u7528\u81ea\u5df1\u5b8c\u6210\u6570\u636e\u642c\u8fd0<\/td>\n<\/tr>\n<tr>\n<td>\u9002\u7528\u573a\u666f<\/td>\n<td>\u72b6\u6001\u53d8\u5316\u68c0\u6d4b&#xff08;\u6309\u952e\u3001\u4f20\u611f\u5668\u3001\u4e32\u53e3\u89e6\u53d1&#xff09;<\/td>\n<td>\u9ad8\u541e\u5410\u91cf\u78c1\u76d8\/\u7f51\u7edc I\/O<\/td>\n<td>\u7b80\u5355\u540c\u6b65\u6570\u636e\u6d41<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u26a0\ufe0f \u91cd\u8981\u533a\u5206&#xff1a;O_ASYNC&#xff08;\u66fe\u7528\u540d FASYNC&#xff09;\u542f\u7528\u7684\u662f\u4fe1\u53f7\u9a71\u52a8 I\/O&#xff08;\u901a\u77e5&#034;\u5c31\u7eea&#034;&#xff09;&#xff0c;\u800c\u975e POSIX AIO&#xff08;\u901a\u77e5&#034;\u5b8c\u6210&#034;&#xff09;\u3002\u4e24\u8005\u540d\u79f0\u76f8\u4f3c\u4f46\u8bed\u4e49\u5b8c\u5168\u4e0d\u540c\u3002<\/p>\n<h4>1.3 \u6574\u4f53\u67b6\u6784<\/h4>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/08\/20260803000840-6a6fdc087854f.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<p>\u4e0a\u56fe\u5c55\u793a\u4e86\u5f02\u6b65\u901a\u77e5\u7684\u56db\u5c42\u67b6\u6784&#xff1a;<\/p>\n<li>\u5e94\u7528\u5c42&#xff1a;\u901a\u8fc7 signal() &#043; fcntl() \u5b8c\u6210\u6ce8\u518c\u4e0e\u542f\u7528&#xff1b;<\/li>\n<li>\u5185\u6838\u5c42&#xff1a;VFS \u7ef4\u62a4 filp-&gt;f_owner \u4e0e filp-&gt;f_flags&#xff0c;\u4fe1\u53f7\u5b50\u7cfb\u7edf\u8d1f\u8d23\u6295\u9012&#xff1b;<\/li>\n<li>\u9a71\u52a8\u5c42&#xff1a;\u5b9e\u73b0 .fasync \u65b9\u6cd5&#xff0c;\u5728\u4e2d\u65ad\u4e2d\u8c03\u7528 kill_fasync() \u53d1\u9001\u4fe1\u53f7&#xff1b;<\/li>\n<li>\u786c\u4ef6\u5c42&#xff1a;\u5916\u8bbe\u901a\u8fc7\u4e2d\u65ad\u63a7\u5236\u5668\u5411 CPU \u53d1\u8d77\u4e2d\u65ad\u8bf7\u6c42\u3002<\/li>\n<hr \/>\n<h3>\u7b2c 2 \u7ae0 \u5e94\u7528\u5c42\u89c6\u89d2&#xff1a;\u5982\u4f55\u63a5\u6536\u5f02\u6b65\u901a\u77e5<\/h3>\n<h4>2.1 \u6838\u5fc3 API \u4ecb\u7ecd<\/h4>\n<h5>2.1.1 signal() \/ sigaction() \u2014\u2014 \u6ce8\u518c\u4fe1\u53f7\u5904\u7406\u51fd\u6570<\/h5>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;signal.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token comment\">\/* \u65b9\u5f0f\u4e00&#xff1a;signal() \u2014\u2014 \u7b80\u5355\u4f46\u53ef\u79fb\u690d\u6027\u8f83\u5f31 *\/<\/span><br \/>\n<span class=\"token keyword\">typedef<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span><span class=\"token class-name\">sighandler_t<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token class-name\">sighandler_t<\/span> <span class=\"token function\">signal<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> signum<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">sighandler_t<\/span> handler<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/* \u65b9\u5f0f\u4e8c&#xff1a;sigaction() \u2014\u2014 \u63a8\u8350&#xff0c;\u652f\u6301 SA_SIGINFO \u83b7\u53d6 siginfo_t *\/<\/span><br \/>\n<span class=\"token keyword\">int<\/span> <span class=\"token function\">sigaction<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> signum<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">sigaction<\/span> <span class=\"token operator\">*<\/span>act<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">sigaction<\/span> <span class=\"token operator\">*<\/span>oldact<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u53c2\u6570\u8bf4\u660e&#xff1a;<\/p>\n<ul>\n<li>signum&#xff1a;\u4fe1\u53f7\u7f16\u53f7&#xff0c;\u5f02\u6b65\u901a\u77e5\u56fa\u5b9a\u4f7f\u7528 SIGIO&#xff08;\u7f16\u53f7 29 on x86&#xff0c;23 on ARM&#xff09;\u3002<\/li>\n<li>handler&#xff1a;\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u3002\u4f7f\u7528 sigaction \u4e14\u8bbe\u7f6e SA_SIGINFO \u65f6&#xff0c;\u53ef\u63a5\u6536 siginfo_t * \u53c2\u6570&#xff0c;\u4ece\u4e2d\u83b7\u53d6\u89e6\u53d1\u4fe1\u53f7\u7684 fd&#xff08;si_fd&#xff09;\u4e0e\u4e8b\u4ef6\u7c7b\u578b&#xff08;si_band&#xff09;\u3002<\/li>\n<\/ul>\n<p>\u8fd4\u56de\u503c&#xff1a;\u6210\u529f\u8fd4\u56de 0&#xff1b;\u5931\u8d25\u8fd4\u56de -1 \u5e76\u8bbe\u7f6e errno\u3002<\/p>\n<h5>2.1.2 fcntl() \u2014\u2014 \u8bbe\u7f6e\u6587\u4ef6\u5c5e\u4e3b\u4e0e FASYNC \u6807\u5fd7<\/h5>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;fcntl.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> cmd<span class=\"token punctuation\">,<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token comment\">\/* arg *\/<\/span> <span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5173\u952e\u547d\u4ee4&#xff1a;<\/p>\n<table>\n<tr>\u547d\u4ee4\u4f5c\u7528\u793a\u4f8b<\/tr>\n<tbody>\n<tr>\n<td>F_SETOWN<\/td>\n<td>\u8bbe\u7f6e\u63a5\u6536 SIGIO \u7684\u8fdb\u7a0b\/\u8fdb\u7a0b\u7ec4 PID<\/td>\n<td>fcntl(fd, F_SETOWN, getpid())<\/td>\n<\/tr>\n<tr>\n<td>F_GETFL<\/td>\n<td>\u83b7\u53d6\u6587\u4ef6\u72b6\u6001\u6807\u5fd7<\/td>\n<td>fcntl(fd, F_GETFL)<\/td>\n<\/tr>\n<tr>\n<td>F_SETFL<\/td>\n<td>\u8bbe\u7f6e\u6587\u4ef6\u72b6\u6001\u6807\u5fd7&#xff08;\u6216\u4e0a FASYNC\/O_ASYNC&#xff09;<\/td>\n<td>fcntl(fd, F_SETFL, flags | FASYNC)<\/td>\n<\/tr>\n<tr>\n<td>F_SETSIG<\/td>\n<td>\u6307\u5b9a\u66ff\u4ee3 SIGIO \u7684\u5b9e\u65f6\u4fe1\u53f7&#xff08;\u53ef\u9009&#xff09;<\/td>\n<td>fcntl(fd, F_SETSIG, SIGRTMIN)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u6ce8\u610f&#xff1a;FASYNC \u4e0e O_ASYNC \u5728 Linux \u4e0b\u8bed\u4e49\u7b49\u4ef7&#xff0c;glibc \u5c06 FASYNC \u5b9a\u4e49\u4e3a O_ASYNC \u7684\u522b\u540d\u3002\u4f46 O_ASYNC \u662f\u6807\u51c6\u540d\u79f0&#xff0c;\u5efa\u8bae\u4f18\u5148\u4f7f\u7528\u3002<\/p>\n<h4>2.2 \u5e94\u7528\u5c42\u542f\u7528\u5f02\u6b65\u901a\u77e5\u7684\u4e09\u6b65\u9aa4<\/h4>\n<p><span class=\"token comment\">\/* \u6b65\u9aa4 1&#xff1a;\u6ce8\u518c SIGIO \u4fe1\u53f7\u5904\u7406\u51fd\u6570 *\/<\/span><br \/>\n<span class=\"token function\">signal<\/span><span class=\"token punctuation\">(<\/span>SIGIO<span class=\"token punctuation\">,<\/span> sigio_handler<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>           <span class=\"token comment\">\/\/ \u6216\u4f7f\u7528 sigaction()<\/span><\/p>\n<p><span class=\"token comment\">\/* \u6b65\u9aa4 2&#xff1a;\u8bbe\u7f6e\u5f53\u524d\u8fdb\u7a0b\u4e3a\u6587\u4ef6\u5c5e\u4e3b *\/<\/span><br \/>\n<span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_SETOWN<span class=\"token punctuation\">,<\/span> <span class=\"token function\">getpid<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/* \u6b65\u9aa4 3&#xff1a;\u542f\u7528 FASYNC \u6807\u5fd7 *\/<\/span><br \/>\n<span class=\"token keyword\">int<\/span> flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> F_SETFL<span class=\"token punctuation\">,<\/span> flags <span class=\"token operator\">|<\/span> FASYNC<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5b8c\u6210\u4ee5\u4e0a\u4e09\u6b65\u540e&#xff0c;\u4e00\u65e6\u9a71\u52a8\u8c03\u7528 kill_fasync() \u53d1\u9001 SIGIO&#xff0c;\u5f53\u524d\u8fdb\u7a0b\u5c31\u4f1a\u8fdb\u5165 sigio_handler\u3002<\/p>\n<h4>2.3 \u5b8c\u6574\u5e94\u7528\u793a\u4f8b<\/h4>\n<p><span class=\"token comment\">\/* app_async_notify.c *\/<\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;stdio.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;stdlib.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;string.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;unistd.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;fcntl.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;signal.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;sys\/types.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token keyword\">int<\/span> async_flag <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">int<\/span> dev_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/* SIGIO \u4fe1\u53f7\u5904\u7406\u51fd\u6570 *\/<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">sigio_handler<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> sig<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">siginfo_t<\/span> <span class=\"token operator\">*<\/span>info<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>context<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">void<\/span><span class=\"token punctuation\">)<\/span>sig<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">void<\/span><span class=\"token punctuation\">)<\/span>context<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/* \u901a\u8fc7 siginfo_t \u83b7\u53d6\u89e6\u53d1\u6e90 fd \u4e0e\u4e8b\u4ef6\u7c7b\u578b *\/<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>info<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;[APP] Received SIGIO, si_fd&#061;%d, si_band&#061;%ld\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span><br \/>\n               info<span class=\"token operator\">-&gt;<\/span>si_fd<span class=\"token punctuation\">,<\/span> info<span class=\"token operator\">-&gt;<\/span>si_band<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    async_flag <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">main<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> argc<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">char<\/span> <span class=\"token operator\">*<\/span>argv<span class=\"token punctuation\">[<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">char<\/span> buf<span class=\"token punctuation\">[<\/span><span class=\"token number\">256<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">sigaction<\/span> sa<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>argc <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">2<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">fprintf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token constant\">stderr<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">&#034;Usage: %s &lt;device&gt;\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> argv<span class=\"token punctuation\">[<\/span><span class=\"token number\">0<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> EXIT_FAILURE<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/* \u6253\u5f00\u8bbe\u5907 *\/<\/span><br \/>\n    dev_fd <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">open<\/span><span class=\"token punctuation\">(<\/span>argv<span class=\"token punctuation\">[<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">,<\/span> O_RDWR<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>dev_fd <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;open&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> EXIT_FAILURE<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/* \u6b65\u9aa4 1&#xff1a;\u4f7f\u7528 sigaction \u6ce8\u518c&#xff0c;\u5e26 SA_SIGINFO \u53ef\u83b7\u53d6\u8be6\u7ec6\u4fe1\u606f *\/<\/span><br \/>\n    <span class=\"token function\">memset<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>sa<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>sa<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    sa<span class=\"token punctuation\">.<\/span>sa_sigaction <span class=\"token operator\">&#061;<\/span> sigio_handler<span class=\"token punctuation\">;<\/span><br \/>\n    sa<span class=\"token punctuation\">.<\/span>sa_flags <span class=\"token operator\">&#061;<\/span> SA_SIGINFO<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">sigemptyset<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>sa<span class=\"token punctuation\">.<\/span>sa_mask<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">sigaction<\/span><span class=\"token punctuation\">(<\/span>SIGIO<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>sa<span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;sigaction&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> EXIT_FAILURE<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/* \u6b65\u9aa4 2&#xff1a;\u8bbe\u7f6e\u5c5e\u4e3b *\/<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">,<\/span> F_SETOWN<span class=\"token punctuation\">,<\/span> <span class=\"token function\">getpid<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl F_SETOWN&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> EXIT_FAILURE<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token comment\">\/* \u6b65\u9aa4 3&#xff1a;\u542f\u7528 FASYNC *\/<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">,<\/span> F_SETFL<span class=\"token punctuation\">,<\/span> flags <span class=\"token operator\">|<\/span> FASYNC<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">perror<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;fcntl F_SETFL FASYNC&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> EXIT_FAILURE<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;[APP] Async notification enabled, waiting for SIGIO&#8230;\\\\n&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/* \u4e3b\u5faa\u73af&#xff1a;\u975e\u963b\u585e\u6267\u884c\u5176\u4ed6\u4efb\u52a1&#xff0c;\u4ec5\u5728\u6536\u5230\u4fe1\u53f7\u65f6\u8bfb\u53d6 *\/<\/span><br \/>\n    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/* \u6a21\u62df\u5176\u4ed6\u4e1a\u52a1\u903b\u8f91 *\/<\/span><br \/>\n        <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">10<\/span> <span class=\"token operator\">&amp;&amp;<\/span> <span class=\"token operator\">!<\/span>async_flag<span class=\"token punctuation\">;<\/span> i<span class=\"token operator\">&#043;&#043;<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token function\">usleep<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">100000<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/* 100ms *\/<\/span><br \/>\n            <span class=\"token function\">putchar<\/span><span class=\"token punctuation\">(<\/span><span class=\"token char\">&#039;.&#039;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token function\">fflush<\/span><span class=\"token punctuation\">(<\/span><span class=\"token constant\">stdout<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><\/p>\n<p>        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>async_flag<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            async_flag <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token function\">memset<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">int<\/span> n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&gt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token function\">printf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;\\\\n[APP] Read %d bytes: %s\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">close<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h4>2.4 \u5e94\u7528\u5c42\u4f7f\u7528\u6ce8\u610f\u4e8b\u9879<\/h4>\n<li>\n<p>\u8fb9\u7f18\u89e6\u53d1&#xff08;Edge-Triggered&#xff09;\u98ce\u9669&#xff1a;SIGIO \u662f\u8fb9\u7f18\u89e6\u53d1\u7684\u3002\u82e5\u6536\u5230\u4fe1\u53f7\u540e\u672a\u5c06\u6570\u636e\u5168\u90e8\u8bfb\u8d70&#xff0c;\u5269\u4f59\u6570\u636e\u4e0d\u4f1a\u518d\u6b21\u89e6\u53d1 SIGIO&#xff0c;\u7a0b\u5e8f\u5c06\u6c38\u8fdc\u6302\u8d77\u3002\u6536\u5230\u4fe1\u53f7\u540e\u5fc5\u987b\u5faa\u73af\u8bfb\u53d6\u76f4\u5230\u8fd4\u56de EAGAIN\u3002<\/p>\n<\/li>\n<li>\n<p>\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u9650\u5236&#xff1a;\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u5904\u4e8e\u5f02\u6b65\u4e0a\u4e0b\u6587&#xff0c;\u53ea\u80fd\u8c03\u7528**\u5f02\u6b65\u4fe1\u53f7\u5b89\u5168&#xff08;async-signal-safe&#xff09;**\u51fd\u6570\u3002\u7981\u6b62\u5728\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4e2d\u8c03\u7528 malloc()\u3001printf()&#xff08;\u6807\u51c6 I\/O \u975e\u5b89\u5168&#xff09;\u3001pthread_mutex_lock() \u7b49\u3002\u793a\u4f8b\u4e2d\u7684 printf \u4ec5\u7528\u4e8e\u6f14\u793a&#xff0c;\u751f\u4ea7\u73af\u5883\u5e94\u4f7f\u7528 write(STDOUT_FILENO, &#8230;) \u6216\u8bbe\u7f6e\u6807\u5fd7\u4f4d\u7531\u4e3b\u5faa\u73af\u5904\u7406\u3002<\/p>\n<\/li>\n<li>\n<p>\u591a\u7ebf\u7a0b\u73af\u5883&#xff1a;F_SETOWN \u8bbe\u7f6e\u7684\u662f\u8fdb\u7a0b\u7ea7\u5c5e\u4e3b\u3002\u82e5\u4f7f\u7528 F_SETOWN_EX&#xff08;Linux 2.6.32&#043;&#xff09;&#xff0c;\u53ef\u7cbe\u786e\u6307\u5b9a\u7ebf\u7a0b ID&#xff08;TID&#xff09;&#xff0c;\u907f\u514d\u4fe1\u53f7\u88ab\u9519\u8bef\u7ebf\u7a0b\u63a5\u6536\u3002<\/p>\n<\/li>\n<li>\n<p>\u5b9e\u65f6\u4fe1\u53f7\u66ff\u4ee3&#xff1a;\u901a\u8fc7 fcntl(fd, F_SETSIG, SIGRTMIN) \u53ef\u6539\u7528\u5b9e\u65f6\u4fe1\u53f7&#xff08;SIGRTMIN~SIGRTMAX&#xff09;&#xff0c;\u652f\u6301\u6392\u961f\u4e0e\u643a\u5e26 siginfo_t&#xff0c;\u907f\u514d\u6807\u51c6\u4fe1\u53f7\u4e22\u5931\u95ee\u9898\u3002<\/p>\n<\/li>\n<li>\n<p>\u6587\u4ef6\u5173\u95ed\u524d\u6e05\u7406&#xff1a;\u5e94\u7528\u9000\u51fa\u524d\u53ea\u9700 close(fd)&#xff0c;\u9a71\u52a8\u7684 release() \u4f1a\u81ea\u52a8\u6e05\u7406\u5f02\u6b65\u961f\u5217\u3002\u4f46\u663e\u5f0f\u5148\u6e05\u9664 FASYNC \u6807\u5fd7\u662f\u66f4\u5b89\u5168\u7684\u505a\u6cd5\u3002<\/p>\n<\/li>\n<hr \/>\n<h3>\u7b2c 3 \u7ae0 \u9a71\u52a8\u5c42\u89c6\u89d2&#xff1a;\u5982\u4f55\u53d1\u9001\u5f02\u6b65\u901a\u77e5<\/h3>\n<h4>3.1 \u6838\u5fc3\u6570\u636e\u7ed3\u6784<\/h4>\n<h5>3.1.1 struct fasync_struct<\/h5>\n<p><span class=\"token comment\">\/* include\/linux\/fs.h *\/<\/span><br \/>\n<span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span>              magic<span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/* \u9b54\u6570\u6821\u9a8c&#xff1a;FASYNC_MAGIC *\/<\/span><br \/>\n    <span class=\"token keyword\">int<\/span>              fa_fd<span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/* \u5173\u8054\u7684\u6587\u4ef6\u63cf\u8ff0\u7b26 *\/<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token operator\">*<\/span>fa_next<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/* \u5f02\u6b65\u961f\u5217\u94fe\u8868\u6307\u9488 *\/<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span>      <span class=\"token operator\">*<\/span>fa_file<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/* \u5173\u8054\u7684 struct file \u6307\u9488 *\/<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6bcf\u4e2a\u6253\u5f00\u8be5\u8bbe\u5907\u7684\u8fdb\u7a0b\u90fd\u4f1a\u5728\u5185\u6838\u4e2d\u5bf9\u5e94\u4e00\u4e2a fasync_struct \u8282\u70b9&#xff0c;\u9a71\u52a8\u901a\u8fc7\u94fe\u8868\u7ba1\u7406\u6240\u6709\u7b49\u5f85\u5f02\u6b65\u901a\u77e5\u7684\u8fdb\u7a0b\u3002<\/p>\n<h5>3.1.2 struct fown_struct<\/h5>\n<p>\u4f4d\u4e8e struct file \u4e2d\u7684 f_owner \u5b57\u6bb5&#xff0c;\u8bb0\u5f55\u4e86\u63a5\u6536\u4fe1\u53f7\u7684\u8fdb\u7a0b\/\u8fdb\u7a0b\u7ec4\u4fe1\u606f&#xff1a;<\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fown_struct<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">rwlock_t<\/span> lock<span class=\"token punctuation\">;<\/span>          <span class=\"token comment\">\/* 5.x&#043; \u5f15\u5165\u8bfb\u5199\u9501\u7ec6\u5316\u5e76\u53d1 *\/<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">pid<\/span> <span class=\"token operator\">*<\/span>pid<span class=\"token punctuation\">;<\/span>        <span class=\"token comment\">\/* \u76ee\u6807\u8fdb\u7a0b *\/<\/span><br \/>\n    <span class=\"token keyword\">enum<\/span> <span class=\"token class-name\">pid_type<\/span> pid_type<span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/* PIDTYPE_PID \/ PIDTYPE_PGID *\/<\/span><br \/>\n    <span class=\"token class-name\">uid_t<\/span> uid<span class=\"token punctuation\">,<\/span> euid<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> signum<span class=\"token punctuation\">;<\/span>             <span class=\"token comment\">\/* F_SETSIG \u6307\u5b9a\u7684\u4fe1\u53f7&#xff0c;0 \u8868\u793a\u9ed8\u8ba4 SIGIO *\/<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>3.2 \u6838\u5fc3 API \u4ecb\u7ecd<\/h4>\n<h5>3.2.1 fasync_helper() \u2014\u2014 \u5f02\u6b65\u961f\u5217\u7ba1\u7406<\/h5>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/fs.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">int<\/span> <span class=\"token function\">fasync_helper<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span> <span class=\"token operator\">*<\/span>filp<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> on<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token operator\">*<\/span><span class=\"token operator\">*<\/span>fapp<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u529f\u80fd&#xff1a;\u5f53\u7528\u6237\u7a7a\u95f4\u901a\u8fc7 fcntl \u6539\u53d8 FASYNC \u6807\u5fd7\u65f6&#xff0c;\u5185\u6838\u8c03\u7528\u9a71\u52a8\u7684 .fasync \u65b9\u6cd5&#xff0c;\u9a71\u52a8\u518d\u5c06\u53c2\u6570\u900f\u4f20\u7ed9 fasync_helper&#xff0c;\u7531\u540e\u8005\u5b8c\u6210 fasync_struct \u8282\u70b9\u7684\u5206\u914d\/\u91ca\u653e\u4e0e\u94fe\u8868\u7ef4\u62a4\u3002<\/p>\n<p>\u53c2\u6570&#xff1a;<\/p>\n<ul>\n<li>fd&#xff1a;\u6587\u4ef6\u63cf\u8ff0\u7b26&#xff08;\u6765\u81ea .fasync \u65b9\u6cd5\u53c2\u6570&#xff09;&#xff1b;<\/li>\n<li>filp&#xff1a;struct file \u6307\u9488&#xff08;\u6765\u81ea .fasync \u65b9\u6cd5\u53c2\u6570&#xff09;&#xff1b;<\/li>\n<li>on&#xff1a;\u975e 0 \u8868\u793a\u6dfb\u52a0\u8282\u70b9&#xff0c;0 \u8868\u793a\u5220\u9664\u8282\u70b9&#xff1b;<\/li>\n<li>fapp&#xff1a;\u6307\u5411\u9a71\u52a8\u4e2d struct fasync_struct * \u6307\u9488\u7684\u5730\u5740\u3002<\/li>\n<\/ul>\n<p>\u8fd4\u56de\u503c&#xff1a;<\/p>\n<ul>\n<li>&gt; 0&#xff1a;\u6210\u529f\u6dfb\u52a0\u6216\u5220\u9664\u4e86\u8282\u70b9&#xff1b;<\/li>\n<li>0&#xff1a;\u672a\u505a\u4efb\u4f55\u4fee\u6539&#xff1b;<\/li>\n<li>&lt; 0&#xff1a;\u5185\u5b58\u5206\u914d\u5931\u8d25&#xff08;-ENOMEM&#xff09;\u3002<\/li>\n<\/ul>\n<h5>3.2.2 kill_fasync() \u2014\u2014 \u53d1\u9001\u5f02\u6b65\u4fe1\u53f7<\/h5>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/fs.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token function\">kill_fasync<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token operator\">*<\/span><span class=\"token operator\">*<\/span>fp<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> sig<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> band<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u529f\u80fd&#xff1a;\u904d\u5386 fp \u6307\u5411\u7684\u5f02\u6b65\u961f\u5217&#xff0c;\u5411\u6bcf\u4e2a\u6ce8\u518c\u7684\u8fdb\u7a0b\u53d1\u9001\u6307\u5b9a\u4fe1\u53f7\u3002<\/p>\n<p>\u53c2\u6570&#xff1a;<\/p>\n<ul>\n<li>fp&#xff1a;\u6307\u5411\u9a71\u52a8\u4e2d struct fasync_struct * \u6307\u9488\u7684\u5730\u5740&#xff08;\u5373 &amp;dev-&gt;async_queue&#xff09;&#xff1b;<\/li>\n<li>sig&#xff1a;\u4fe1\u53f7\u7f16\u53f7&#xff0c;\u901a\u5e38\u4e3a SIGIO&#xff1b;<\/li>\n<li>band&#xff1a;\u4e8b\u4ef6\u7c7b\u578b&#xff0c;\u5e38\u7528 POLL_IN&#xff08;\u53ef\u8bfb&#xff09;\u3001POLL_OUT&#xff08;\u53ef\u5199&#xff09;\u3001POLL_ERR&#xff08;\u9519\u8bef&#xff09;\u3002<\/li>\n<\/ul>\n<p>\u6ce8\u610f&#xff1a;kill_fasync() \u5185\u90e8\u4f1a\u8c03\u7528 send_sigio() \u2192 send_sig_info()&#xff0c;\u6700\u7ec8\u901a\u8fc7\u4fe1\u53f7\u5b50\u7cfb\u7edf\u5c06\u4fe1\u53f7\u63d2\u5165\u76ee\u6807\u8fdb\u7a0b\u7684\u6302\u8d77\u961f\u5217\u3002\u8be5\u51fd\u6570\u53ef\u5728\u4e2d\u65ad\u4e0a\u4e0b\u6587\u5b89\u5168\u8c03\u7528\u3002<\/p>\n<h4>3.3 \u9a71\u52a8\u5b9e\u73b0\u56db\u6b65\u9aa4<\/h4>\n<p><span class=\"token comment\">\/* \u6b65\u9aa4 1&#xff1a;\u5728\u8bbe\u5907\u7ed3\u6784\u4f53\u4e2d\u5b9a\u4e49 fasync_struct \u6307\u9488 *\/<\/span><br \/>\n<span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">my_dev<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token operator\">*<\/span>async_queue<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token comment\">\/* &#8230; \u5176\u4ed6\u5b57\u6bb5 &#8230; *\/<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/* \u6b65\u9aa4 2&#xff1a;\u5b9e\u73b0 .fasync \u65b9\u6cd5 *\/<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token function\">my_fasync<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span> <span class=\"token operator\">*<\/span>filp<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> on<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">my_dev<\/span> <span class=\"token operator\">*<\/span>dev <span class=\"token operator\">&#061;<\/span> filp<span class=\"token operator\">-&gt;<\/span>private_data<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token function\">fasync_helper<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> filp<span class=\"token punctuation\">,<\/span> on<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>dev<span class=\"token operator\">-&gt;<\/span>async_queue<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/* \u6b65\u9aa4 3&#xff1a;\u5728\u6570\u636e\u5c31\u7eea\/\u4e8b\u4ef6\u53d1\u751f\u65f6\u8c03\u7528 kill_fasync *\/<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token class-name\">irqreturn_t<\/span> <span class=\"token function\">my_irq_handler<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> irq<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>dev_id<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">my_dev<\/span> <span class=\"token operator\">*<\/span>dev <span class=\"token operator\">&#061;<\/span> dev_id<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token comment\">\/* &#8230; \u5904\u7406\u786c\u4ef6\u4e8b\u4ef6 &#8230; *\/<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>dev<span class=\"token operator\">-&gt;<\/span>async_queue<span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token function\">kill_fasync<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>dev<span class=\"token operator\">-&gt;<\/span>async_queue<span class=\"token punctuation\">,<\/span> SIGIO<span class=\"token punctuation\">,<\/span> POLL_IN<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> IRQ_HANDLED<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/* \u6b65\u9aa4 4&#xff1a;\u5728 release() \u4e2d\u6e05\u7406 *\/<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token function\">my_release<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">inode<\/span> <span class=\"token operator\">*<\/span>inode<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span> <span class=\"token operator\">*<\/span>filp<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">my_dev<\/span> <span class=\"token operator\">*<\/span>dev <span class=\"token operator\">&#061;<\/span> filp<span class=\"token operator\">-&gt;<\/span>private_data<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token comment\">\/* \u53c2\u6570 fd&#061;-1, on&#061;0 \u8868\u793a\u5f3a\u5236\u79fb\u9664 *\/<\/span><br \/>\n    <span class=\"token function\">my_fasync<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> filp<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file_operations<\/span> my_fops <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span>owner   <span class=\"token operator\">&#061;<\/span> THIS_MODULE<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span>fasync  <span class=\"token operator\">&#061;<\/span> my_fasync<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span>release <span class=\"token operator\">&#061;<\/span> my_release<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token comment\">\/* &#8230; *\/<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>3.4 \u5b8c\u6574\u9a71\u52a8\u793a\u4f8b<\/h4>\n<p><span class=\"token comment\">\/* drv_async_notify.c \u2014\u2014 \u7b80\u5316\u7248\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8 *\/<\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/module.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/kernel.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/fs.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/cdev.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/device.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/interrupt.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/uaccess.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/wait.h&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;linux\/poll.h&gt;<\/span><\/span><\/p>\n<p><span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">define<\/span> <span class=\"token macro-name\">DEVICE_NAME<\/span> <span class=\"token string\">&#034;async_demo&#034;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">define<\/span> <span class=\"token macro-name\">CLASS_NAME<\/span>  <span class=\"token string\">&#034;async_cls&#034;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token keyword\">int<\/span> major<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">class<\/span> <span class=\"token operator\">*<\/span>async_class<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">device<\/span> <span class=\"token operator\">*<\/span>async_device<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">cdev<\/span> async_cdev<span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token function\">DECLARE_WAIT_QUEUE_HEAD<\/span><span class=\"token punctuation\">(<\/span>read_waitq<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">volatile<\/span> <span class=\"token keyword\">int<\/span> data_ready <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">char<\/span> kbuf<span class=\"token punctuation\">[<\/span><span class=\"token number\">256<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token operator\">*<\/span>async_queue <span class=\"token operator\">&#061;<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/* &#061;&#061;&#061; .fasync \u65b9\u6cd5 &#061;&#061;&#061; *\/<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token function\">async_demo_fasync<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span> <span class=\"token operator\">*<\/span>filp<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> on<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">printk<\/span><span class=\"token punctuation\">(<\/span>KERN_INFO <span class=\"token string\">&#034;[%s] fasync called: fd&#061;%d, on&#061;%d\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> DEVICE_NAME<span class=\"token punctuation\">,<\/span> fd<span class=\"token punctuation\">,<\/span> on<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token function\">fasync_helper<\/span><span class=\"token punctuation\">(<\/span>fd<span class=\"token punctuation\">,<\/span> filp<span class=\"token punctuation\">,<\/span> on<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>async_queue<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/* &#061;&#061;&#061; \u6a21\u62df\u4e2d\u65ad\/\u4e8b\u4ef6\u89e6\u53d1 &#061;&#061;&#061; *\/<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token class-name\">ssize_t<\/span> <span class=\"token function\">async_demo_write<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span> <span class=\"token operator\">*<\/span>filp<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token keyword\">char<\/span> __user <span class=\"token operator\">*<\/span>buf<span class=\"token punctuation\">,<\/span><br \/>\n                                <span class=\"token class-name\">size_t<\/span> count<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">loff_t<\/span> <span class=\"token operator\">*<\/span>pos<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">size_t<\/span> n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">min<\/span><span class=\"token punctuation\">(<\/span>count<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>kbuf<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#8211;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">copy_from_user<\/span><span class=\"token punctuation\">(<\/span>kbuf<span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token operator\">&#8211;<\/span>EFAULT<span class=\"token punctuation\">;<\/span><br \/>\n    kbuf<span class=\"token punctuation\">[<\/span>n<span class=\"token punctuation\">]<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token char\">&#039;\\\\0&#039;<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    data_ready <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/* \u5524\u9192\u963b\u585e\u8bfb *\/<\/span><br \/>\n    <span class=\"token function\">wake_up_interruptible<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>read_waitq<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/* \u53d1\u9001\u5f02\u6b65\u901a\u77e5 *\/<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>async_queue<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">kill_fasync<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>async_queue<span class=\"token punctuation\">,<\/span> SIGIO<span class=\"token punctuation\">,<\/span> POLL_IN<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">printk<\/span><span class=\"token punctuation\">(<\/span>KERN_INFO <span class=\"token string\">&#034;[%s] SIGIO sent to registered processes\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> DEVICE_NAME<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token keyword\">return<\/span> n<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/* &#061;&#061;&#061; read \u65b9\u6cd5 &#061;&#061;&#061; *\/<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token class-name\">ssize_t<\/span> <span class=\"token function\">async_demo_read<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span> <span class=\"token operator\">*<\/span>filp<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">char<\/span> __user <span class=\"token operator\">*<\/span>buf<span class=\"token punctuation\">,<\/span><br \/>\n                               <span class=\"token class-name\">size_t<\/span> count<span class=\"token punctuation\">,<\/span> <span class=\"token class-name\">loff_t<\/span> <span class=\"token operator\">*<\/span>pos<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">wait_event_interruptible<\/span><span class=\"token punctuation\">(<\/span>read_waitq<span class=\"token punctuation\">,<\/span> data_ready<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token class-name\">size_t<\/span> n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">min<\/span><span class=\"token punctuation\">(<\/span>count<span class=\"token punctuation\">,<\/span> <span class=\"token function\">strlen<\/span><span class=\"token punctuation\">(<\/span>kbuf<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token function\">copy_to_user<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">,<\/span> kbuf<span class=\"token punctuation\">,<\/span> n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token operator\">&#8211;<\/span>EFAULT<span class=\"token punctuation\">;<\/span><\/p>\n<p>    data_ready <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> n<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/* &#061;&#061;&#061; release \u65b9\u6cd5&#xff1a;\u5fc5\u987b\u6e05\u7406\u5f02\u6b65\u961f\u5217 &#061;&#061;&#061; *\/<\/span><br \/>\n<span class=\"token keyword\">static<\/span> <span class=\"token keyword\">int<\/span> <span class=\"token function\">async_demo_release<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">inode<\/span> <span class=\"token operator\">*<\/span>inode<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span> <span class=\"token operator\">*<\/span>filp<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">async_demo_fasync<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&#8211;<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> filp<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">printk<\/span><span class=\"token punctuation\">(<\/span>KERN_INFO <span class=\"token string\">&#034;[%s] release: async queue cleaned\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> DEVICE_NAME<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file_operations<\/span> async_demo_fops <span class=\"token operator\">&#061;<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span>owner   <span class=\"token operator\">&#061;<\/span> THIS_MODULE<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span>write   <span class=\"token operator\">&#061;<\/span> async_demo_write<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span>read    <span class=\"token operator\">&#061;<\/span> async_demo_read<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span>fasync  <span class=\"token operator\">&#061;<\/span> async_demo_fasync<span class=\"token punctuation\">,<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span>release <span class=\"token operator\">&#061;<\/span> async_demo_release<span class=\"token punctuation\">,<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token keyword\">int<\/span> __init <span class=\"token function\">async_demo_init<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">void<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">dev_t<\/span> devno<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">alloc_chrdev_region<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>devno<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span> DEVICE_NAME<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    major <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">MAJOR<\/span><span class=\"token punctuation\">(<\/span>devno<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token function\">cdev_init<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>async_cdev<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">&amp;<\/span>async_demo_fops<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">cdev_add<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>async_cdev<span class=\"token punctuation\">,<\/span> devno<span class=\"token punctuation\">,<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    async_class <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">class_create<\/span><span class=\"token punctuation\">(<\/span>THIS_MODULE<span class=\"token punctuation\">,<\/span> CLASS_NAME<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    async_device <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">device_create<\/span><span class=\"token punctuation\">(<\/span>async_class<span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span> devno<span class=\"token punctuation\">,<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">,<\/span> DEVICE_NAME<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token function\">printk<\/span><span class=\"token punctuation\">(<\/span>KERN_INFO <span class=\"token string\">&#034;[%s] loaded, major&#061;%d\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> DEVICE_NAME<span class=\"token punctuation\">,<\/span> major<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token keyword\">void<\/span> __exit <span class=\"token function\">async_demo_exit<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">void<\/span><span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token function\">device_destroy<\/span><span class=\"token punctuation\">(<\/span>async_class<span class=\"token punctuation\">,<\/span> <span class=\"token function\">MKDEV<\/span><span class=\"token punctuation\">(<\/span>major<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">class_destroy<\/span><span class=\"token punctuation\">(<\/span>async_class<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">cdev_del<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>async_cdev<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">unregister_chrdev_region<\/span><span class=\"token punctuation\">(<\/span><span class=\"token function\">MKDEV<\/span><span class=\"token punctuation\">(<\/span>major<span class=\"token punctuation\">,<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">printk<\/span><span class=\"token punctuation\">(<\/span>KERN_INFO <span class=\"token string\">&#034;[%s] unloaded\\\\n&#034;<\/span><span class=\"token punctuation\">,<\/span> DEVICE_NAME<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token function\">module_init<\/span><span class=\"token punctuation\">(<\/span>async_demo_init<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">module_exit<\/span><span class=\"token punctuation\">(<\/span>async_demo_exit<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">MODULE_LICENSE<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;GPL&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token function\">MODULE_DESCRIPTION<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;Linux Async Notification Demo Driver&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h4>3.5 \u9a71\u52a8\u5c42\u4f7f\u7528\u6ce8\u610f\u4e8b\u9879<\/h4>\n<li>\n<p>\u5fc5\u987b\u5b9e\u73b0 .fasync \u65b9\u6cd5&#xff1a;\u82e5 file_operations \u4e2d\u672a\u63d0\u4f9b .fasync&#xff0c;\u7528\u6237\u7a7a\u95f4\u8bbe\u7f6e FASYNC \u5c06\u4e0d\u4f1a\u751f\u6548&#xff0c;\u5185\u6838\u65e0\u6cd5\u5efa\u7acb\u5f02\u6b65\u961f\u5217\u3002<\/p>\n<\/li>\n<li>\n<p>kill_fasync() \u524d\u5224\u7a7a&#xff1a;\u867d\u7136 kill_fasync() \u5185\u90e8\u6709\u4fdd\u62a4&#xff0c;\u4f46\u663e\u5f0f\u5224\u65ad if (dev-&gt;async_queue) \u53ef\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u51fd\u6570\u8c03\u7528\u5f00\u9500&#xff0c;\u4e14\u4ee3\u7801\u8bed\u4e49\u66f4\u6e05\u6670\u3002<\/p>\n<\/li>\n<li>\n<p>release() \u4e2d\u5f3a\u5236\u6e05\u7406&#xff1a;\u8c03\u7528 .fasync(-1, filp, 0) \u5c06\u5f53\u524d filp \u4ece\u5f02\u6b65\u961f\u5217\u4e2d\u79fb\u9664\u3002\u82e5\u9057\u6f0f\u6b64\u6b65\u9aa4&#xff0c;\u8fdb\u7a0b\u5173\u95ed fd \u540e\u4ecd\u53ef\u80fd\u6536\u5230\u4fe1\u53f7&#xff0c;\u5bfc\u81f4 SIGIO \u88ab\u6295\u9012\u5230\u5df2\u4e0d\u5b58\u5728\u7684\u8fdb\u7a0b\u4e0a\u4e0b\u6587\u3002<\/p>\n<\/li>\n<li>\n<p>\u4e2d\u65ad\u4e0a\u4e0b\u6587\u5b89\u5168&#xff1a;kill_fasync() \u5185\u90e8\u4f7f\u7528 spin_lock_irqsave(&amp;fasync_lock, &#8230;) \u4fdd\u62a4\u94fe\u8868\u904d\u5386&#xff0c;\u56e0\u6b64\u53ef\u5728\u786c\u4e2d\u65ad\/\u8f6f\u4e2d\u65ad\/\u8fdb\u7a0b\u4e0a\u4e0b\u6587\u4efb\u610f\u8c03\u7528\u3002\u4f46\u5efa\u8bae\u5728\u4e2d\u65ad\u4e0a\u534a\u90e8&#xff08;ISR&#xff09;\u4e2d\u5feb\u901f\u8c03\u7528\u540e\u7acb\u5373\u8fd4\u56de&#xff0c;\u590d\u6742\u903b\u8f91\u79fb\u81f3\u4e0b\u534a\u90e8&#xff08;tasklet\/workqueue&#xff09;\u3002<\/p>\n<\/li>\n<li>\n<p>\u591a\u8fdb\u7a0b\u5e76\u53d1\u8bbf\u95ee&#xff1a;fasync_helper() \u5185\u90e8\u4f7f\u7528\u5168\u5c40 fasync_lock&#xff08;\u81ea\u65cb\u9501&#xff09;\u4fdd\u62a4\u94fe\u8868\u64cd\u4f5c\u3002\u9a71\u52a8\u65e0\u9700\u989d\u5916\u52a0\u9501&#xff0c;\u4f46\u9700\u6ce8\u610f fasync_struct \u6307\u9488\u672c\u8eab\u7684\u5185\u5b58\u53ef\u89c1\u6027&#xff08;\u5efa\u8bae\u7528 struct fasync_struct * \u800c\u975e\u88f8\u6307\u9488\u6570\u7ec4&#xff09;\u3002<\/p>\n<\/li>\n<hr \/>\n<h3>\u7b2c 4 \u7ae0 \u5185\u6838\u7248\u672c\u6f14\u8fdb&#xff1a;\u4ece Device Tree \u5230 6.x<\/h3>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/08\/20260803000843-6a6fdc0bcbee6.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<h4>4.1 2.6.x \u65f6\u671f&#xff1a;\u57fa\u7840\u6846\u67b6\u6210\u719f\u4e0e Device Tree \u840c\u82bd<\/h4>\n<ul>\n<li>2.3.21&#043;&#xff1a;kill_fasync() \u5f15\u5165\u7b2c\u4e09\u4e2a\u53c2\u6570 band&#xff08;POLL_IN\/POLL_OUT&#xff09;&#xff0c;\u5728\u6b64\u4e4b\u524d\u4ec5\u6709\u4e24\u4e2a\u53c2\u6570&#xff08;struct fasync_struct *queue, int signal&#xff09;\u3002<\/li>\n<li>2.6.x&#xff1a;fasync_helper() \u4e0e kill_fasync() \u63a5\u53e3\u5b8c\u5168\u5b9a\u578b&#xff0c;\u6210\u4e3a\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8\u6807\u51c6\u8303\u5f0f\u3002<\/li>\n<li>Device Tree \u840c\u82bd&#xff1a;2005~2008 \u5e74&#xff0c;PowerPC \u67b6\u6784\u7387\u5148\u5f15\u5165 Device Tree \u4ee5\u89e3\u51b3\u5d4c\u5165\u5f0f\u677f\u7ea7\u4ee3\u7801\u81c3\u80bf\u95ee\u9898\u3002\u6b64\u65f6 ARM \u4ecd\u4f7f\u7528\u786c\u7f16\u7801\u7684 arch\/arm\/mach-*\/board-*.c\u3002<\/li>\n<\/ul>\n<h4>4.2 3.x \u65f6\u671f&#xff1a;Device Tree \u6807\u51c6\u5316\u4e0e ARM \u67b6\u6784\u7edf\u4e00<\/h4>\n<ul>\n<li>Linux 3.0 (2011)&#xff1a;Device Tree \u6b63\u5f0f\u5408\u5e76\u5165\u4e3b\u7ebf&#xff0c;\u6210\u4e3a ARM SoC \u7684\u6807\u51c6\u786c\u4ef6\u63cf\u8ff0\u65b9\u5f0f\u3002<\/li>\n<li>\u5bf9\u5f02\u6b65\u901a\u77e5\u7684\u5f71\u54cd&#xff1a;platform_driver \u5f00\u59cb\u901a\u8fc7 of_match_table \u7ed1\u5b9a Device Tree \u8282\u70b9\u3002\u9a71\u52a8\u5f00\u53d1\u8005\u4e0d\u518d\u9700\u8981\u5173\u5fc3\u677f\u7ea7\u5dee\u5f02&#xff0c;.fasync \u7684\u5b9e\u73b0\u903b\u8f91\u4e0e\u786c\u4ef6\u63cf\u8ff0\u89e3\u8026&#xff0c;\u9a71\u52a8\u53ef\u590d\u7528\u6027\u5927\u5e45\u63d0\u5347\u3002<\/li>\n<li>RCU \u4fdd\u62a4\u5f15\u5165&#xff1a;3.x \u540e\u671f\u5f00\u59cb\u5bf9 fasync \u76f8\u5173\u94fe\u8868\u8fdb\u884c RCU \u8bfb\u7aef\u4fdd\u62a4&#xff0c;\u51cf\u5c11 fasync_lock \u81ea\u65cb\u9501\u7684\u4e89\u7528\u3002<\/li>\n<\/ul>\n<h4>4.3 4.x \u65f6\u671f&#xff1a;\u5b89\u5168\u589e\u5f3a\u4e0e\u5b9e\u65f6\u4fe1\u53f7\u5b8c\u5584<\/h4>\n<ul>\n<li>4.14&#043;&#xff1a;send_sigio() \u5185\u90e8\u5b9e\u73b0\u589e\u5f3a&#xff0c;\u5bf9 siginfo_t \u7684\u6784\u9020\u66f4\u52a0\u4e25\u8c28&#xff0c;si_uid \u4e0e si_fd \u7684\u586b\u5145\u903b\u8f91\u4fee\u6b63\u4e86\u65e9\u671f\u7248\u672c\u4e2d\u7684\u91cd\u53e0\u95ee\u9898\u3002<\/li>\n<li>\u5b9e\u65f6\u4fe1\u53f7\u652f\u6301&#xff1a;fcntl(fd, F_SETSIG, rt_signal) \u5728 4.x \u7cfb\u5217\u4e2d\u5f97\u5230\u5b8c\u5584&#xff0c;\u5b9e\u65f6\u4fe1\u53f7\u53ef\u643a\u5e26\u5b8c\u6574\u7684 siginfo_t \u4fe1\u606f&#xff0c;\u89e3\u51b3\u4e86\u6807\u51c6 SIGIO \u4e0d\u6392\u961f\u3001\u53ef\u80fd\u4e22\u5931\u7684\u95ee\u9898\u3002<\/li>\n<li>cgroup v1 \u4fe1\u53f7\u9694\u79bb&#xff1a;4.x \u5f15\u5165\u7684 cgroup \u673a\u5236\u5f00\u59cb\u5bf9\u4fe1\u53f7\u6295\u9012\u8fdb\u884c\u547d\u540d\u7a7a\u95f4\u7ea7\u9694\u79bb&#xff0c;\u786e\u4fdd\u5bb9\u5668\u5185\u8fdb\u7a0b\u4e0d\u4f1a\u6536\u5230\u5bb9\u5668\u5916\u8bbe\u5907\u7684 SIGIO\u3002<\/li>\n<\/ul>\n<h4>4.4 5.x \u65f6\u671f&#xff1a;\u5e76\u53d1\u4f18\u5316\u4e0e\u5468\u8fb9\u5b50\u7cfb\u7edf\u534f\u540c<\/h4>\n<ul>\n<li>5.x&#xff1a;struct file \u4e2d\u7684 f_owner \u5b57\u6bb5\u4ece\u7b80\u5355\u7684\u8bfb\u5199\u9501\u4fdd\u62a4\u5347\u7ea7\u4e3a\u66f4\u7ec6\u7c92\u5ea6\u7684 rwlock_t&#xff0c;\u51cf\u5c11\u4e86\u9ad8\u5e76\u53d1\u573a\u666f\u4e0b\u591a\u8fdb\u7a0b\u540c\u65f6\u6ce8\u518c\/\u6ce8\u9500 FASYNC \u7684\u9501\u4e89\u7528\u3002<\/li>\n<li>lockdep \u589e\u5f3a&#xff1a;\u5185\u6838\u6b7b\u9501\u68c0\u6d4b\u5de5\u5177 lockdep \u589e\u52a0\u4e86\u5bf9 fasync_lock \u7684\u4f9d\u8d56\u56fe\u5206\u6790&#xff0c;\u5e2e\u52a9\u9a71\u52a8\u5f00\u53d1\u8005\u53d1\u73b0\u6f5c\u5728\u7684\u6b7b\u9501\u98ce\u9669\u3002<\/li>\n<li>\u65e0\u6838\u5fc3 API \u53d8\u66f4&#xff1a;fasync_helper() \u4e0e kill_fasync() \u7684\u51fd\u6570\u539f\u578b\u5728 5.x \u5168\u7cfb\u5217\u4fdd\u6301\u4e0d\u53d8&#xff0c;\u4f53\u73b0\u4e86\u5185\u6838 API \u7684\u5411\u540e\u517c\u5bb9\u627f\u8bfa\u3002<\/li>\n<\/ul>\n<h4>4.5 6.x \u65f6\u671f&#xff1a;\u5411\u540e\u517c\u5bb9\u4e0e\u65b0\u8303\u5f0f\u5e76\u5b58<\/h4>\n<ul>\n<li>6.x&#xff1a;fasync \u673a\u5236\u672c\u8eab\u65e0\u7834\u574f\u6027\u53d8\u66f4&#xff0c;\u4fdd\u6301\u5b8c\u5168\u5411\u540e\u517c\u5bb9\u3002\u4f46\u5185\u6838\u793e\u533a\u66f4\u63a8\u8350\u4f7f\u7528 io_uring &#043; poll \u4f5c\u4e3a\u9ad8\u6027\u80fd\u5f02\u6b65\u4e8b\u4ef6\u901a\u77e5\u7684\u65b0\u8303\u5f0f\u3002<\/li>\n<li>cgroup v2 \u4fe1\u53f7\u9694\u79bb&#xff1a;6.x \u8fdb\u4e00\u6b65\u5b8c\u5584\u4e86 cgroup v2 \u4e0b\u7684\u4fe1\u53f7\u6295\u9012\u7b56\u7565&#xff0c;\u652f\u6301\u901a\u8fc7 cgroup.subtree_control \u5bf9 SIGIO \u8fdb\u884c\u5c42\u7ea7\u9694\u79bb\u3002<\/li>\n<li>BPF \u4e0e fasync&#xff1a;6.x \u5f15\u5165\u4e86\u66f4\u591a BPF \u94a9\u5b50\u70b9&#xff0c;\u5141\u8bb8\u5728\u4fe1\u53f7\u6295\u9012\u8def\u5f84\u4e0a\u6302\u8f7d BPF \u7a0b\u5e8f\u8fdb\u884c\u5ba1\u8ba1\u6216\u8fc7\u6ee4&#xff0c;\u4e3a\u5b89\u5168\u654f\u611f\u573a\u666f\u63d0\u4f9b\u4e86\u65b0\u9009\u62e9\u3002<\/li>\n<\/ul>\n<h4>4.6 \u7248\u672c\u5dee\u5f02\u901f\u67e5\u8868<\/h4>\n<table>\n<tr>\u7248\u672cfasync_helperkill_fasync.fasync \u65b9\u6cd5\u7b7e\u540d\u5173\u952e\u53d8\u5316<\/tr>\n<tbody>\n<tr>\n<td>2.0<\/td>\n<td>inode \u53c2\u6570<\/td>\n<td>\u4e24\u53c2\u6570&#xff08;\u65e0 band&#xff09;<\/td>\n<td>int (*fasync)(struct inode*, struct file*, int)<\/td>\n<td>\u65e9\u671f\u5b9e\u73b0<\/td>\n<\/tr>\n<tr>\n<td>2.3.21&#043;<\/td>\n<td>\u7a33\u5b9a\u63a5\u53e3<\/td>\n<td>\u4e09\u53c2\u6570&#xff08;&#043;band&#xff09;<\/td>\n<td>int (*fasync)(int fd, struct file*, int)<\/td>\n<td>band \u53c2\u6570\u5f15\u5165<\/td>\n<\/tr>\n<tr>\n<td>2.6.x<\/td>\n<td>\u6807\u51c6\u63a5\u53e3<\/td>\n<td>POLL_IN\/OUT<\/td>\n<td>\u540c\u4e0a<\/td>\n<td>\u8bbe\u5907\u6811\u840c\u82bd&#xff08;PowerPC&#xff09;<\/td>\n<\/tr>\n<tr>\n<td>3.x&#043;<\/td>\n<td>RCU \u4fdd\u62a4<\/td>\n<td>send_sigio \u589e\u5f3a<\/td>\n<td>\u540c\u4e0a<\/td>\n<td>ARM DT \u6807\u51c6\u5316<\/td>\n<\/tr>\n<tr>\n<td>4.14&#043;<\/td>\n<td>fasync_lock<\/td>\n<td>siginfo_t \u5b8c\u5584<\/td>\n<td>\u540c\u4e0a<\/td>\n<td>\u5b89\u5168\u4e0e\u5b9e\u65f6\u6027\u589e\u5f3a<\/td>\n<\/tr>\n<tr>\n<td>5.x&#043;<\/td>\n<td>\u65e0\u53d8\u5316<\/td>\n<td>\u65e0\u53d8\u5316<\/td>\n<td>\u540c\u4e0a<\/td>\n<td>\u5468\u8fb9\u5b50\u7cfb\u7edf\u4f18\u5316<\/td>\n<\/tr>\n<tr>\n<td>6.x&#043;<\/td>\n<td>\u5411\u540e\u517c\u5bb9<\/td>\n<td>\u5411\u540e\u517c\u5bb9<\/td>\n<td>\u540c\u4e0a<\/td>\n<td>io_uring \u66ff\u4ee3\u8d8b\u52bf<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<hr \/>\n<h3>\u7b2c 5 \u7ae0 \u673a\u5236\u6df1\u5165\u89e3\u6790<\/h3>\n<h4>5.1 SIGIO \u4fe1\u53f7\u6295\u9012\u5b8c\u6574\u6d41\u7a0b<\/h4>\n<p><img decoding=\"async\" src=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/08\/20260803000846-6a6fdc0e45aa6.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<p>\u4e0a\u56fe\u5c06\u4fe1\u53f7\u6295\u9012\u5212\u5206\u4e3a\u56db\u4e2a\u9636\u6bb5&#xff1a;<\/p>\n<p>\u9636\u6bb5 1 \u2014\u2014 \u786c\u4ef6\u89e6\u53d1&#xff1a;\u5916\u8bbe\u4ea7\u751f\u4e8b\u4ef6 \u2192 \u4e2d\u65ad\u63a7\u5236\u5668&#xff08;GIC\/APIC&#xff09;\u5206\u53d1 \u2192 CPU \u54cd\u5e94 IRQ \u2192 \u8fdb\u5165 ISR&#xff08;\u5173\u4e2d\u65ad\/\u4fdd\u5b58\u4e0a\u4e0b\u6587&#xff09;\u3002<\/p>\n<p>\u9636\u6bb5 2 \u2014\u2014 \u9a71\u52a8\u54cd\u5e94&#xff1a;ISR \u8bfb\u53d6\u72b6\u6001\u5bc4\u5b58\u5668\u786e\u8ba4\u4e8b\u4ef6\u6e90 \u2192 \u8c03\u7528 kill_fasync() \u2192 \u904d\u5386 fasync_struct \u5f02\u6b65\u961f\u5217\u94fe\u8868 \u2192 \u83b7\u53d6 filp-&gt;f_owner \u4e2d\u7684\u76ee\u6807\u8fdb\u7a0b PID\u3002<\/p>\n<p>\u9636\u6bb5 3 \u2014\u2014 \u5185\u6838\u6295\u9012&#xff1a;send_sigio() \u6784\u9020 siginfo_t&#xff08;\u586b\u5145 si_signo&#061;SIGIO\u3001si_code&#061;SI_SIGIO\u3001si_fd&#061;fa_fd\u3001si_band&#061;POLL_IN&#xff09;\u2192 send_sig_info() \u5c06\u4fe1\u53f7\u63d2\u5165\u76ee\u6807\u8fdb\u7a0b\u7684 shared_pending \u961f\u5217 \u2192 \u8fdb\u7a0b\u8c03\u5ea6\u65f6\u68c0\u67e5\u5e76\u9012\u9001\u4fe1\u53f7\u3002<\/p>\n<p>\u9636\u6bb5 4 \u2014\u2014 \u7528\u6237\u5904\u7406&#xff1a;\u8fdb\u7a0b\u4ece\u5185\u6838\u6001\u8fd4\u56de\u7528\u6237\u6001 \u2192 do_signal() \u5904\u7406\u6302\u8d77\u4fe1\u53f7 \u2192 \u8c03\u7528\u7528\u6237\u6ce8\u518c\u7684 SIGIO \u4fe1\u53f7\u5904\u7406\u51fd\u6570 \u2192 \u7528\u6237\u7a0b\u5e8f\u6267\u884c read() \u6216\u4e1a\u52a1\u903b\u8f91\u3002<\/p>\n<h4>5.2 fasync_helper() \u5185\u90e8\u5b9e\u73b0\u8981\u70b9<\/h4>\n<p><span class=\"token comment\">\/* \u7b80\u5316\u903b\u8f91&#xff0c;\u57fa\u4e8e 4.14&#043; \u5185\u6838 *\/<\/span><br \/>\n<span class=\"token keyword\">int<\/span> <span class=\"token function\">fasync_helper<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> fd<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">file<\/span> <span class=\"token operator\">*<\/span>filp<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> on<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token operator\">*<\/span><span class=\"token operator\">*<\/span>fapp<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token operator\">*<\/span>fa<span class=\"token punctuation\">,<\/span> <span class=\"token operator\">*<\/span><span class=\"token operator\">*<\/span>fp<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">fasync_struct<\/span> <span class=\"token operator\">*<\/span>new <span class=\"token operator\">&#061;<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> result <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>on<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        new <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">kmem_cache_alloc<\/span><span class=\"token punctuation\">(<\/span>fasync_cache<span class=\"token punctuation\">,<\/span> GFP_KERNEL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">!<\/span>new<span class=\"token punctuation\">)<\/span><br \/>\n            <span class=\"token keyword\">return<\/span> <span class=\"token operator\">&#8211;<\/span>ENOMEM<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><\/p>\n<p>    <span class=\"token function\">write_lock_irq<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>fasync_lock<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>    <span class=\"token comment\">\/* \u5168\u5c40\u81ea\u65cb\u9501\u4fdd\u62a4 *\/<\/span><br \/>\n    <span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span>fp <span class=\"token operator\">&#061;<\/span> fapp<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">(<\/span>fa <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">*<\/span>fp<span class=\"token punctuation\">)<\/span> <span class=\"token operator\">!&#061;<\/span> <span class=\"token constant\">NULL<\/span><span class=\"token punctuation\">;<\/span> fp <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&amp;<\/span>fa<span class=\"token operator\">-&gt;<\/span>fa_next<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>fa<span class=\"token operator\">-&gt;<\/span>fa_file <span class=\"token operator\">&#061;&#061;<\/span> filp<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>   <span class=\"token comment\">\/* \u5df2\u5b58\u5728\u8be5 filp \u7684\u8282\u70b9 *\/<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>on<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                fa<span class=\"token operator\">-&gt;<\/span>fa_fd <span class=\"token operator\">&#061;<\/span> fd<span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/* \u66f4\u65b0 fd *\/<\/span><br \/>\n                <span class=\"token function\">kmem_cache_free<\/span><span class=\"token punctuation\">(<\/span>fasync_cache<span class=\"token punctuation\">,<\/span> new<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span> <span class=\"token keyword\">else<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n                <span class=\"token operator\">*<\/span>fp <span class=\"token operator\">&#061;<\/span> fa<span class=\"token operator\">-&gt;<\/span>fa_next<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/* \u4ece\u94fe\u8868\u6458\u9664 *\/<\/span><br \/>\n                <span class=\"token function\">kmem_cache_free<\/span><span class=\"token punctuation\">(<\/span>fasync_cache<span class=\"token punctuation\">,<\/span> fa<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n                result <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n            <span class=\"token punctuation\">}<\/span><br \/>\n            <span class=\"token keyword\">goto<\/span> out<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>on<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        new<span class=\"token operator\">-&gt;<\/span>magic <span class=\"token operator\">&#061;<\/span> FASYNC_MAGIC<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/* \u9b54\u6570\u6821\u9a8c&#xff0c;\u9632\u6b62\u5185\u5b58\u635f\u574f *\/<\/span><br \/>\n        new<span class=\"token operator\">-&gt;<\/span>fa_file <span class=\"token operator\">&#061;<\/span> filp<span class=\"token punctuation\">;<\/span><br \/>\n        new<span class=\"token operator\">-&gt;<\/span>fa_fd <span class=\"token operator\">&#061;<\/span> fd<span class=\"token punctuation\">;<\/span><br \/>\n        new<span class=\"token operator\">-&gt;<\/span>fa_next <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">*<\/span>fapp<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token operator\">*<\/span>fapp <span class=\"token operator\">&#061;<\/span> new<span class=\"token punctuation\">;<\/span><br \/>\n        result <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">1<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\nout<span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">write_unlock_irq<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>fasync_lock<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> result<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5173\u952e\u8bbe\u8ba1&#xff1a;<\/p>\n<ul>\n<li>\u4f7f\u7528 slab \u7f13\u5b58&#xff08;fasync_cache&#xff09;\u5206\u914d\u8282\u70b9&#xff0c;\u907f\u514d\u9891\u7e41\u8c03\u7528\u901a\u7528\u5185\u5b58\u5206\u914d\u5668&#xff1b;<\/li>\n<li>\u4f7f\u7528 \u5168\u5c40\u81ea\u65cb\u9501 fasync_lock&#xff08;write_lock_irq&#xff09;\u4fdd\u8bc1\u94fe\u8868\u64cd\u4f5c\u7684\u539f\u5b50\u6027&#xff1b;<\/li>\n<li>\u901a\u8fc7 fa_file &#061;&#061; filp \u5339\u914d\u8282\u70b9&#xff0c;\u786e\u4fdd\u6bcf\u4e2a struct file \u5b9e\u4f8b\u5728\u94fe\u8868\u4e2d\u552f\u4e00\u3002<\/li>\n<\/ul>\n<h4>5.3 \u8fb9\u7f18\u89e6\u53d1\u7279\u6027\u4e0e\u6570\u636e\u6392\u7a7a<\/h4>\n<p>SIGIO \u5c5e\u4e8e**\u8fb9\u7f18\u89e6\u53d1&#xff08;Edge-Triggered&#xff09;**\u901a\u77e5&#xff1a;<\/p>\n<p>\u4ec5\u5f53\u8bbe\u5907\u72b6\u6001\u4ece&#034;\u672a\u5c31\u7eea&#034;\u8df3\u53d8\u5230&#034;\u5c31\u7eea&#034;\u65f6\u53d1\u9001\u4e00\u6b21\u4fe1\u53f7\u3002\u82e5\u5e94\u7528\u672a\u5c06\u6570\u636e\u5168\u90e8\u8bfb\u8d70&#xff0c;\u72b6\u6001\u4e0d\u4f1a\u56de\u9000\u5230&#034;\u672a\u5c31\u7eea&#034;&#xff0c;\u56e0\u6b64\u4e0d\u4f1a\u4ea7\u751f\u7b2c\u4e8c\u6b21\u8df3\u53d8&#xff0c;\u4e5f\u5c31\u4e0d\u4f1a\u6709\u65b0\u7684 SIGIO\u3002<\/p>\n<p>\u6b63\u786e\u505a\u6cd5&#xff1a;<\/p>\n<p><span class=\"token keyword\">static<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">sigio_handler<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> sig<span class=\"token punctuation\">)<\/span><br \/>\n<span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> flags <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">,<\/span> F_GETFL<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token function\">fcntl<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">,<\/span> F_SETFL<span class=\"token punctuation\">,<\/span> flags <span class=\"token operator\">|<\/span> O_NONBLOCK<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/* \u8bbe\u4e3a\u975e\u963b\u585e *\/<\/span><\/p>\n<p>    <span class=\"token keyword\">while<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">char<\/span> buf<span class=\"token punctuation\">[<\/span><span class=\"token number\">256<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">int<\/span> n <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">read<\/span><span class=\"token punctuation\">(<\/span>dev_fd<span class=\"token punctuation\">,<\/span> buf<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span>buf<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>n <span class=\"token operator\">&lt;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n            <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>errno <span class=\"token operator\">&#061;&#061;<\/span> EAGAIN <span class=\"token operator\">||<\/span> errno <span class=\"token operator\">&#061;&#061;<\/span> EWOULDBLOCK<span class=\"token punctuation\">)<\/span><br \/>\n                <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/* \u6570\u636e\u5df2\u6392\u7a7a *\/<\/span><br \/>\n            <span class=\"token comment\">\/* \u5176\u4ed6\u9519\u8bef\u5904\u7406 *\/<\/span><br \/>\n            <span class=\"token keyword\">break<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token punctuation\">}<\/span><br \/>\n        <span class=\"token comment\">\/* \u5904\u7406 buf \u4e2d\u7684 n \u5b57\u8282\u6570\u636e *\/<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<hr \/>\n<h3>\u7b2c 6 \u7ae0 \u6700\u4f73\u5b9e\u8df5\u4e0e\u5e38\u89c1\u95ee\u9898<\/h3>\n<h4>6.1 \u6700\u4f73\u5b9e\u8df5\u6e05\u5355<\/h4>\n<table>\n<tr>\u573a\u666f\u63a8\u8350\u505a\u6cd5<\/tr>\n<tbody>\n<tr>\n<td>\u4fe1\u53f7\u6ce8\u518c<\/td>\n<td>\u4f18\u5148\u4f7f\u7528 sigaction() &#043; SA_SIGINFO&#xff0c;\u907f\u514d signal() \u7684\u53ef\u79fb\u690d\u6027\u95ee\u9898<\/td>\n<\/tr>\n<tr>\n<td>\u591a\u7ebf\u7a0b<\/td>\n<td>\u4f7f\u7528 F_SETOWN_EX \u7cbe\u786e\u6307\u5b9a TID&#xff0c;\u6216\u7edf\u4e00\u7531\u4e3b\u7ebf\u7a0b\u63a5\u6536\u540e\u5206\u53d1<\/td>\n<\/tr>\n<tr>\n<td>\u4fe1\u53f7\u5b89\u5168<\/td>\n<td>\u4fe1\u53f7\u5904\u7406\u51fd\u6570\u4e2d\u4ec5\u4fee\u6539 volatile sig_atomic_t \u6807\u5fd7&#xff0c;\u4e3b\u5faa\u73af\u6267\u884c I\/O<\/td>\n<\/tr>\n<tr>\n<td>\u6570\u636e\u6392\u7a7a<\/td>\n<td>\u6536\u5230 SIGIO \u540e\u5faa\u73af read() \u76f4\u5230 EAGAIN&#xff0c;\u9632\u6b62\u8fb9\u7f18\u89e6\u53d1\u6f0f\u4e8b\u4ef6<\/td>\n<\/tr>\n<tr>\n<td>\u9a71\u52a8\u5b9e\u73b0<\/td>\n<td>.fasync \u65b9\u6cd5\u5fc5\u987b\u900f\u4f20\u53c2\u6570\u7ed9 fasync_helper()&#xff1b;release() \u4e2d\u5fc5\u987b\u8c03\u7528 .fasync(-1, filp, 0)<\/td>\n<\/tr>\n<tr>\n<td>\u5b9e\u65f6\u6027\u8981\u6c42<\/td>\n<td>\u4f7f\u7528 fcntl(F_SETSIG, SIGRTMIN) \u66ff\u4ee3 SIGIO&#xff0c;\u652f\u6301\u4fe1\u53f7\u6392\u961f<\/td>\n<\/tr>\n<tr>\n<td>\u9ad8\u5e76\u53d1<\/td>\n<td>\u8003\u8651 epoll &#043; O_NONBLOCK \u6216 io_uring \u66ff\u4ee3 fasync&#xff0c;\u51cf\u5c11\u4fe1\u53f7\u5f00\u9500<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h4>6.2 \u5e38\u89c1\u95ee\u9898 FAQ<\/h4>\n<p>Q1&#xff1a;\u5e94\u7528\u8bbe\u7f6e\u4e86 FASYNC&#xff0c;\u4f46\u6536\u4e0d\u5230 SIGIO&#xff1f;<\/p>\n<p>\u6392\u67e5\u6b65\u9aa4&#xff1a;<\/p>\n<li>\u9a71\u52a8\u662f\u5426\u5b9e\u73b0\u4e86 .fasync \u65b9\u6cd5&#xff1f;<\/li>\n<li>fasync_helper() \u8fd4\u56de\u503c\u662f\u5426\u68c0\u67e5&#xff1f;<\/li>\n<li>\u6570\u636e\u5c31\u7eea\u65f6\u662f\u5426\u8c03\u7528\u4e86 kill_fasync()&#xff1f;<\/li>\n<li>fcntl(F_SETOWN) \u8bbe\u7f6e\u7684 PID \u662f\u5426\u6b63\u786e&#xff1f;<\/li>\n<li>\u662f\u5426\u88ab\u4fe1\u53f7\u63a9\u7801\u963b\u585e&#xff08;sigprocmask&#xff09;&#xff1f;<\/li>\n<p>Q2&#xff1a;kill_fasync() \u53ef\u4ee5\u5728\u4e2d\u65ad\u4e0a\u4e0b\u6587\u8c03\u7528\u5417&#xff1f;<\/p>\n<p>\u53ef\u4ee5\u3002kill_fasync() \u2192 send_sigio() \u2192 send_sig_info() \u5168\u7a0b\u4f7f\u7528\u81ea\u65cb\u9501\u4e0e RCU&#xff0c;\u4e0d\u8c03\u7528\u53ef\u80fd\u7761\u7720\u7684\u51fd\u6570&#xff0c;\u56e0\u6b64\u53ef\u5728\u786c\u4e2d\u65ad\u3001\u8f6f\u4e2d\u65ad\u3001tasklet \u4e2d\u5b89\u5168\u8c03\u7528\u3002<\/p>\n<p>Q3&#xff1a;\u591a\u4e2a\u8fdb\u7a0b\u540c\u65f6\u6253\u5f00\u8bbe\u5907&#xff0c;\u90fd\u80fd\u6536\u5230 SIGIO \u5417&#xff1f;<\/p>\n<p>\u53ef\u4ee5\u3002fasync_helper() \u4e3a\u6bcf\u4e2a filp \u521b\u5efa\u4e00\u4e2a fasync_struct \u8282\u70b9&#xff0c;\u6240\u6709\u8282\u70b9\u6302\u5728\u540c\u4e00\u6761\u94fe\u8868\u4e0a\u3002kill_fasync() \u4f1a\u904d\u5386\u94fe\u8868\u5411\u6bcf\u4e2a\u8282\u70b9\u5bf9\u5e94\u7684\u8fdb\u7a0b\u53d1\u9001\u4fe1\u53f7\u3002<\/p>\n<p>Q4&#xff1a;6.x \u5185\u6838\u4e0b fasync \u662f\u5426\u5df2\u88ab\u5e9f\u5f03&#xff1f;<\/p>\n<p>\u672a\u88ab\u5e9f\u5f03&#xff0c;\u4ecd\u5b8c\u5168\u652f\u6301\u3002\u4f46\u793e\u533a\u63a8\u8350\u65b0\u9879\u76ee\u4f18\u5148\u8003\u8651 io_uring&#xff08;\u901a\u8fc7 IORING_OP_POLL_ADD \u5b9e\u73b0\u5f02\u6b65\u4e8b\u4ef6\u901a\u77e5&#xff09;&#xff0c;\u5176\u6027\u80fd\u4e0e\u53ef\u6269\u5c55\u6027\u4f18\u4e8e\u4fe1\u53f7\u9a71\u52a8\u6a21\u578b\u3002<\/p>\n<p>Q5&#xff1a;Device Tree \u4e0e\u5f02\u6b65\u901a\u77e5\u6709\u4ec0\u4e48\u5173\u7cfb&#xff1f;<\/p>\n<p>Device Tree \u672c\u8eab\u4e0d\u76f4\u63a5\u6539\u53d8 fasync \u673a\u5236&#xff0c;\u4f46\u5b83\u6539\u53d8\u4e86\u9a71\u52a8\u7684\u7ec4\u7ec7\u65b9\u5f0f&#xff1a;<\/p>\n<ul>\n<li>\u9a71\u52a8\u901a\u8fc7 compatible \u5b57\u7b26\u4e32\u4e0e DT \u8282\u70b9\u7ed1\u5b9a&#xff0c;\u4e0d\u518d\u4f9d\u8d56\u677f\u7ea7\u6587\u4ef6&#xff1b;<\/li>\n<li>\u4e2d\u65ad\u8d44\u6e90\u901a\u8fc7 interrupts \/ interrupt-parent \u5c5e\u6027\u63cf\u8ff0&#xff0c;\u7531\u5185\u6838\u81ea\u52a8\u89e3\u6790\u5e76\u8c03\u7528 request_irq()&#xff1b;<\/li>\n<li>\u9a71\u52a8\u4ee3\u7801\u66f4\u7eaf\u7cb9&#xff0c;.fasync \u7684\u5b9e\u73b0\u4e0e\u786c\u4ef6\u63cf\u8ff0\u5b8c\u5168\u89e3\u8026\u3002<\/li>\n<\/ul>\n<hr \/>\n","protected":false},"excerpt":{"rendered":"<p>Linux \u5f02\u6b65\u901a\u77e5\u673a\u5236&#xff08;fasync \/ SIGIO&#xff09;\u7b80\u6790 \u9002\u7528\u5185\u6838\u7248\u672c&#xff1a;2.6.x ~ 6.x \u76ee\u5f55<br \/>\n\u7b2c 1 \u7ae0 \u5f02\u6b65\u901a\u77e5\u673a\u5236\u6982\u8ff0\u7b2c 2 \u7ae0 \u5e94\u7528\u5c42\u89c6\u89d2&#xff1a;\u5982\u4f55\u63a5\u6536\u5f02\u6b65\u901a\u77e5\u7b2c 3 \u7ae0 \u9a71\u52a8\u5c42\u89c6\u89d2&#xff1a;\u5982\u4f55\u53d1\u9001\u5f02\u6b65\u901a\u77e5\u7b2c 4 \u7ae0 \u5185\u6838\u7248\u672c\u6f14\u8fdb&#xff1a;\u4ece Device Tree \u5230 6.x\u7b2c 5 \u7ae0 \u673a\u5236\u6df1\u5165\u89e3\u6790\u7b2c 6 \u7ae0 \u6700\u4f73\u5b9e\u8df5\u4e0e\u5e38\u89c1\u95ee\u9898 \u7b2c 1 \u7ae0 \u5f02\u6b65\u901a\u77e5\u673a\u5236\u6982\u8ff0<br \/>\n1.1 \u4ec0\u4e48\u662f\u5f02\u6b65\u901a\u77e5<br \/>\nL<\/p>\n","protected":false},"author":2,"featured_media":89531,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[10155,10156],"topic":[],"class_list":["post-89534","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-linux","tag-10156"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.3 - 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