{"id":1895,"date":"2010-10-27T21:24:22","date_gmt":"2010-10-27T13:24:22","guid":{"rendered":"http:\/\/edsionte.com\/techblog\/?p=1895"},"modified":"2010-11-09T09:05:29","modified_gmt":"2010-11-09T01:05:29","slug":"%e6%94%af%e6%8c%81%e9%98%bb%e5%a1%9e%e6%93%8d%e4%bd%9c%e7%9a%84%e5%ad%97%e7%ac%a6%e8%ae%be%e5%a4%87%e9%a9%b1%e5%8a%a8","status":"publish","type":"post","link":"http:\/\/edsionte.com\/techblog\/archives\/1895","title":{"rendered":"\u652f\u6301\u963b\u585e\u64cd\u4f5c\u7684\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8"},"content":{"rendered":"

\u5728\u524d\u6587<\/a>\u4e2d\uff0c\u6211\u4eec\u5df2\u7ecf\u77e5\u9053\u4e86\u5982\u4f55\u7f16\u5199\u4e00\u4e2a\u7b80\u5355\u7684\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8\u3002\u672c\u6587\u5c06\u5728\u6b64\u57fa\u7840\u4e0a\u4e3a\u8fd9\u4e2a\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8\u589e\u52a0\u963b\u585e\u529f\u80fd\u3002\u4e0d\u8fc7\u5728\u6b64\u4e4b\u524d\uff0c\u6211\u4eec\u4f1a\u5148\u505a\u4e00\u4e9b\u51c6\u5907\u5de5\u4f5c\u3002<\/p>\n

\u963b\u585e\u548c\u975e\u963b\u585eI\/O<\/strong><\/p>\n

\u963b\u585e\u548c\u975e\u963b\u585eI\/O\u662f\u8bbe\u5907\u8bbf\u95ee\u5185\u6838\u7684\u4e24\u79cd\u4e0d\u540c\u7684\u6a21\u5f0f\u3002\u8fdb\u7a0b\u4ee5\u963b\u585e\u65b9\u5f0f\u8bbf\u95ee\u8bbe\u5907\u5e76\u5bf9\u5176\u8fdb\u884c\u64cd\u4f5c\u65f6\uff0c\u5982\u679c\u4e0d\u80fd\u53ca\u65f6\u83b7\u5f97I\/O\u8d44\u6e90\u5219\u4f1a\u88ab\u6302\u8d77\uff0c\u76f4\u5230\u6ee1\u8db3\u53ef\u64cd\u4f5c\u7684\u6761\u4ef6\u540e\u624d\u8fdb\u884c\u76f8\u5e94\u7684\u64cd\u4f5c\u3002\u8fd9\u4e2a\u88ab\u6302\u8d77\u7684\u8fdb\u7a0b\u4f1a\u8fdb\u5165\u7761\u7720\u72b6\u6001\uff0c\u5e76\u88ab\u79fb\u81f3\u67d0\u4e2a\u7b49\u5f85\u961f\u5217\uff1b\u5f53\u6761\u4ef6\u6ee1\u8db3\u65f6\u5019\uff0c\u4f1a\u88ab\u79fb\u51fa\u8fd9\u4e2a\u7b49\u5f85\u961f\u5217\u3002\u8fd9\u91cc\u6240\u8bf4\u7684\u7b49\u5f85\u961f\u5217\u4ee5\u53ca\u76f8\u5173\u64cd\u4f5c\u5728\u4e0a\u6587<\/a>\u5df2\u8bf4\u660e\uff0c\u5728\u6b64\u4e0d\u518d\u8d58\u8ff0\u3002\u975e\u963b\u585e\u65b9\u5f0f\u662f\u6307\u8fdb\u7a0b\u5728\u4e0d\u80fd\u8fdb\u884c\u8bbe\u5907\u64cd\u4f5c\u65f6\u5e76\u4e0d\u88ab\u6302\u8d77\uff0c\u5b83\u8981\u4e48\u653e\u5f03\u64cd\u4f5c\uff0c\u8981\u4e48\u4e0d\u505c\u8fdb\u884c\u67e5\u8be2\uff0c\u76f4\u81f3\u53ef\u4ee5\u8fdb\u884c\u76f8\u5173\u7684\u8bbe\u5907\u64cd\u4f5c\u4e3a\u6b62\u3002<\/p>\n

\u6211\u4eec\u73b0\u5728\u5df2\u7ecf\u77e5\u9053\uff0c\u7528\u6237\u7a7a\u95f4\u4e2d\u7684\u5e94\u7528\u7a0b\u5e8f\u901a\u8fc7read()\u548cwrite()\u7b49\u7edf\u4e00\u7684\u7cfb\u7edf\u8c03\u7528\u6765\u8bbf\u95ee\u8bbe\u5907\u6587\u4ef6\u3002\u800c\u8fd9\u4e9b\u7cfb\u7edf\u8c03\u7528\u51fd\u6570\u6700\u7ec8\u5219\u4f1a\u8c03\u7528\u8bbe\u5907\u9a71\u52a8\u4e2d\u7684XXX_read()\u548cXXX_write()\u51fd\u6570\u3002\u56e0\u6b64\uff0c\u5982\u679c\u6211\u4eec\u5728\u8bbe\u5907\u9a71\u52a8\u4e2d\u5b9e\u73b0\u4e86\u963b\u585e\u529f\u80fd\uff08\u5177\u4f53\u4f1a\u843d\u5b9e\u5230\u67d0\u4e2a\u64cd\u4f5c\u51fd\u6570\uff09\uff0c\u5f53\u5e94\u7528\u7a0b\u5e8f\u8fdb\u7a0b\u4e0d\u80fd\u53ca\u65f6\u83b7\u5f97\u8bbe\u5907\u8d44\u6e90\u65f6\u5c31\u4f1a\u5c06\u8be5\u8fdb\u7a0b\u963b\u585e\u5230\u8d44\u6e90\u53ef\u8bbf\u95ee\u4e3a\u6b62\u3002\u90a3\u4e48XXX_read()\u548cXXX_write()\u7b49\u51fd\u6570\u4e5f\u5c31\u4e0d\u4f1a\u7acb\u5373\u8fd4\u56de\uff0cread()\u548cwrite()\u7b49\u7cfb\u7edf\u8c03\u7528\u4e5f\u5c31\u4e0d\u4f1a\u7acb\u5373\u8fd4\u56de\u3002\u6574\u4e2a\u963b\u585e-\u5524\u9192\u7684\u8fc7\u7a0b\u7528\u6237\u662f\u65e0\u6cd5\u611f\u77e5\u5230\u7684\u3002\u4ece\u7528\u6237\u7684\u89d2\u5ea6\u6765\u770b\uff0c\u4ed6\u4eec\u4f1a\u8ba4\u4e3a\u76f4\u63a5\u5c31\u53ef\u4ee5\u5bf9\u6b64\u8bbe\u5907\u8fdb\u884c\u64cd\u4f5c\u3002<\/p>\n

\u76f8\u53cd\uff0c\u5982\u679c\u8bbe\u5907\u9a71\u52a8\u4e2d\u7684\u64cd\u4f5c\u51fd\u6570\u662f\u975e\u963b\u585e\u7684\uff0c\u90a3\u4e48\u5f53\u8bbe\u5907\u8d44\u6e90\u4e0d\u53ef\u7528\u65f6\uff0c\u8bbe\u5907\u9a71\u52a8\u4e2d\u7684XXX_read()\u548cXXX_write()\u7b49\u51fd\u6570\u4f1a\u7acb\u5373\u8fd4\u56de\uff0c\u90a3\u4e48read()\u548cwrite()\u7b49\u7cfb\u7edf\u8c03\u7528\u4e5f\u4f1a\u7acb\u5373\u8fd4\u56de\u3002\u4ece\u7528\u6237\u89d2\u5ea6\u6765\u770b\uff0c\u6b64\u65f6\u8bbf\u95ee\u8bbe\u5907\u6587\u4ef6\u5c31\u51fa\u9519\u4e86\u3002<\/p>\n

\u652f\u6301\u963b\u585e\u64cd\u4f5c\u7684\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8<\/strong><\/p>\n

\u63a5\u4e0b\u6765\u8981\u5206\u6790\u7684\u8fd9\u4e2a\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8\u540c\u6837\u4f7f\u7528\u4e00\u4e2a\u5168\u5c40\u7684\u5b57\u7b26\u4e32\u6570\u7ec4globalmem\u6765\u5b58\u50a8\u5b57\u7b26\u6570\u636e\u3002XXX_read()\u8d1f\u8d23\u5c06\u5185\u6838\u7a7a\u95f4\u7684\u6570\u636e\uff08\u6b64\u5904\u5373\u4e3aglobalmem\u4e2d\u7684\u5b57\u7b26\u4e32\uff09\u62f7\u8d1d\u5230\u7528\u6237\u7a7a\u95f4\uff0c\u5b9e\u73b0\u7528\u6237\u7a7a\u95f4\u5bf9\u8bbe\u5907\u6587\u4ef6\u7684\u8bfb\u64cd\u4f5c\uff1bXXX_write()\u8d1f\u8d23\u5c06\u7528\u6237\u7a7a\u95f4\u7684\u6570\u636e\u62f7\u8d1d\u5230\u5185\u6838\u7a7a\u95f4\uff0c\u5b9e\u73b0\u7528\u6237\u7a7a\u95f4\u5bf9\u8be5\u8bbe\u5907\u6587\u4ef6\u7684\u5199\u64cd\u4f5c\u3002\u53e6\u5916\uff0c\u4e3a\u4e86\u66f4\u597d\u7684\u6f14\u793a\u672c\u6587\u6240\u8ff0\u7684\u963b\u585e\u64cd\u4f5c\uff0c\u6211\u4eec\u5bf9\u8fd9\u4e2a\u5b57\u7b26\u4e32\u6570\u7ec4globalmem\u8fdb\u884c\u8fd9\u6837\u7684\u9650\u5236\uff1a\u5f53\u5b83\u4e3a\u7a7a\u65f6\uff0c\u8bfb\u8fdb\u7a0b\u4e0d\u80fd\u8fdb\u884c\u8bfb\u64cd\u4f5c\uff1b\u5f53\u5b83\u4e3a\u6ee1\u7684\u65f6\u5019\uff0c\u5199\u8fdb\u7a0b\u4e0d\u80fd\u8fdb\u884c\u5199\u64cd\u4f5c\u3002\u5f53\u8bfb\u4e86count\u5b57\u8282\u7684\u6570\u636e\u540e\uff0c\u8fd8\u8981\u5c06globalmem\u4e2d\u8fd9\u4e9b\u88ab\u8bfb\u7684\u6570\u636e\u79fb\u51fa\u8fd9\u4e2a\u5168\u5c40\u6570\u7ec4\u3002<\/p>\n

\u5982\u679c\u4f60\u7406\u89e3\u4e86\u524d\u9762\u90a3\u4e2a<\/a>\u6700\u57fa\u672c\u7684\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8\u7684\u8bdd\uff0c\u9664\u4e86\u4e0a\u8ff0\u7684\u4e0d\u540c\u5916\uff0c\u57fa\u672c\u4e0a\u6ca1\u6709\u4ec0\u4e48\u5730\u65b9\u4f60\u770b\u4e0d\u61c2\u7684\u3002\u8fd9\u4e2a\u4e3e\u4f8b\u7684\u5b8c\u6574\u4ee3\u7801\u5728\u8fd9\u91cc<\/a>\u3002<\/p>\n

static char globalmem[BUF_NUM];\r\nstatic wait_queue_head_t rdwait;\r\nstatic wait_queue_head_t wrwait;\r\nstatic struct semaphore mutex;\r\n\r\nstatic int len;\r\nssize_t myblock_read(struct file*,char*,size_t count,loff_t*);\r\nssize_t myblock_write(struct file*,char*,size_t count,loff_t*);\r\n\r\nstruct file_operations fops=\r\n{\r\n\t.read=myblock_read,\r\n\t.write=myblock_write,\r\n};\r\n\r\nstatic int __init myblock_init(void)\r\n{\r\n\tint ret;\r\n\r\n\tprintk(\"myblock module is working..\\n\");\r\n\r\n\tret=register_chrdev(MAJOR_NUM,\"edsionte_block_cdev\",&fops);\r\n\tif(ret<0)\r\n\t{\r\n\t\tprintk(\"register failed..\\n\");\r\n\t\treturn 0;\r\n\t}\r\n\telse\r\n\t{\r\n\t\tprintk(\"register success..\\n\");\r\n\t}\r\n\tinit_MUTEX(&mutex);\r\n\tinit_waitqueue_head(&rdwait);\r\n\tinit_waitqueue_head(&wrwait);\r\n\r\n\treturn 0;\r\n}<\/pre>\n
\u5728\u5185\u6838\u6a21\u5757\u52a0\u8f7d\u51fd\u6570\u4e2d\uff0c\u5148\u7533\u8bf7\u5b57\u7b26\u8bbe\u5907\u53f7\uff1b\u518d\u521d\u59cb\u5316\u4e92\u65a5\u4fe1\u53f7\u91cfmutex\uff1b\u6700\u540e\u5206\u522b\u521d\u59cb\u5316\u4e86\u8bfb\u7b49\u5f85\u961f\u5217\u5934\u548c\u5199\u7b49\u5f85\u961f\u5217\u5934\u3002\u53e6\u5916\u5b9a\u4e49\u4e86\u4e00\u4e2a\u5168\u5c40\u53d8\u91cflen\u6765\u8bb0\u5f55\u5f53\u524dglobalmem\u4e2d\u5b9e\u9645\u7684\u5b57\u8282\u6570\uff0c\u800cBUF_NUM\u5219\u662f\u6700\u5927\u957f\u5ea6\u3002<\/p>\n
\u5728\u8bfb\u51fd\u6570\u4e2d\uff0c\u6211\u4eec\u5148\u521b\u5efa\u4e00\u4e2a\u4ee3\u8868\u5f53\u524d\u8fdb\u7a0b\u7684\u7b49\u5f85\u961f\u5217\u7ed3\u70b9wait\uff0c\u5e76\u628a\u5b83\u52a0\u5165\u5230\u8bfb\u7b49\u5f85\u961f\u5217\u5f53\u4e2d\u3002\u4f46\u8fd9\u5e76\u4e0d\u610f\u5473\u7740\u5f53\u524d\u8fdb\u7a0b\u5c31\u5df2\u7ecf\u5b8c\u5168\u7761\u7720\u4e86\uff0c\u8fd8\u9700\u8981\u8c03\u5ea6\u51fd\u6570\u7684\u8c03\u5ea6\u3002\u6211\u4eec\u524d\u9762\u5df2\u7ecf\u8bf4\u8fc7\uff0c\u5f53\u5171\u4eab\u6570\u636e\u533a\u7684\u6570\u636e\u957f\u5ea6\u4e3a0\u65f6\uff0c\u5c31\u5e94\u8be5\u963b\u585e\u8be5\u8fdb\u7a0b\u3002\u56e0\u6b64\uff0c\u5728\u5faa\u73af\u4e2d\uff0c\u9996\u5148\u5c06\u5f53\u524d\u8fdb\u7a0b\u7684\u72b6\u6001\u8bbe\u7f6eTASK_INTERRUPTIBLE\u3002\u7136\u540e\u5229\u7528schedule\u51fd\u6570\u8fdb\u884c\u91cd\u65b0\u8c03\u5ea6\uff0c\u6b64\u65f6\uff0c\u8bfb\u8fdb\u7a0b\u624d\u4f1a\u771f\u6b63\u7684\u7761\u7720\uff0c\u76f4\u81f3\u88ab\u5199\u8fdb\u7a0b\u5524\u9192\u3002\u5728\u7761\u7720\u9014\u4e2d\uff0c\u5982\u679c\u7528\u6237\u7ed9\u8bfb\u8fdb\u7a0b\u53d1\u9001\u4e86\u4fe1\u53f7\uff0c\u90a3\u4e48\u4e5f\u4f1a\u5524\u9192\u7761\u7720\u7684\u8fdb\u7a0b\u3002<\/span><\/p>\n
\u5f53\u5171\u4eab\u6570\u636e\u533a\u6709\u6570\u636e\u65f6\uff0c\u4f1a\u5c06count\u5b57\u8282\u7684\u6570\u636e\u62f7\u8d1d\u5230\u7528\u6237\u7a7a\u95f4\uff0c\u5e76\u4e14\u5524\u9192\u6b63\u5728\u7761\u7720\u7684\u5199\u8fdb\u7a0b\u3002\u5f53\u4e0a\u8ff0\u5de5\u4f5c\u5b8c\u6210\u540e\uff0c\u4f1a\u5c06\u5f53\u524d\u8fdb\u7a0b\u4ece\u8bfb\u7b49\u5f85\u961f\u5217\u4e2d\u79fb\u9664\uff0c\u5e76\u4e14\u5c06\u5f53\u524d\u8fdb\u7a0b\u7684\u72b6\u6001\u8bbe\u7f6e\u4e3aTASK_RUNNING\u3002<\/p>\n
\u5173\u4e8e\u4ece\u5168\u5c40\u7f13\u51b2\u533a\u79fb\u51fa\u5df2\u8bfb\u6570\u636e\uff0c\u8fd9\u91cc\u8981\u7279\u522b\u8bf4\u660e\u4e00\u4e0b\u3002\u8fd9\u91cc\u5229\u7528\u4e86memcpy\u51fd\u6570\u5c06\u4ee5\uff08globalmem+count\uff09\u5f00\u59cb\u7684\uff08len-count\uff09\u5b57\u8282\u7684\u6570\u636e\u79fb\u52a8\u5230\u7f13\u51b2\u533a\u6700\u5f00\u59cb\u7684\u5730\u65b9\u3002<\/p>\n
\u53e6\u5916\uff0c\u5728\u4e0a\u8ff0\u64cd\u4f5c\u8fc7\u7a0b\u4e2d\uff0c\u8fd8\u52a0\u5165\u4e86\u4e92\u65a5\u4fe1\u53f7\u91cf\u9632\u6b62\u591a\u4e2a\u8fdb\u7a0b\u540c\u65f6\u8bbf\u95ee\u5171\u4eab\u6570\u636elen\u548cglobalmem\u3002<\/p>\n
ssize_t myblock_read(struct file*fp,char*buf,size_t count,loff_t*offp)\r\n{\r\n\tint ret;\r\n\tDECLARE_WAITQUEUE(wait,current);\r\n\r\n\tdown(&mutex);\r\n\tadd_wait_queue(&rdwait,&wait);\r\n\r\n\twhile(len==0)\r\n\t{\r\n\t\t__set_current_state(TASK_INTERRUPTIBLE);\r\n\t\tup(&mutex);\r\n\t\tschedule();\r\n\t\tif(signal_pending(current))\r\n\t\t{\r\n\t\t\tret=-1;\r\n\t\t\tgoto signal_out;\r\n\t\t}\r\n\r\n\t\tdown(&mutex);\r\n\t}\r\n\r\n\tif(count>len)\r\n\t{\r\n\t\tcount=len;\r\n\t}\r\n\r\n\tif(copy_to_user(buf,globalmem,count)==0)\r\n\t{\r\n\t\tmemcpy(globalmem,globalmem+count,len-count);\r\n\t\tlen-=count;\r\n\t\tprintk(\"read %d bytes\\n\",count);\r\n\t\twake_up_interruptible(&wrwait);\r\n\t\tret=count;\r\n\t}\r\n\telse\r\n\t{\r\n\t\tret=-1;\r\n\t\tgoto copy_err_out;\r\n\t}\r\n\r\ncopy_err_out:up(&mutex);\r\nsignal_out:remove_wait_queue(&rdwait,&wait);\r\n\r\n\tset_current_state(TASK_RUNNING);\r\n\treturn ret;\r\n}<\/pre>\n
\u5728\u5199\u51fd\u6570\u4e2d\uff0c\u5982\u679c\u68c0\u6d4b\u5230globalmem\u5f53\u524d\u7684\u957f\u5ea6\u662fBUF_NUM\uff0c\u5219\u963b\u585e\u5f53\u524d\u7684\u8fdb\u7a0b\uff1b\u5426\u5219\uff0c\u4ece\u7528\u6237\u7a7a\u95f4\u5c06\u6570\u636e\u62f7\u8d1d\u5230\u5185\u6838\u7a7a\u95f4\u3002\u5199\u51fd\u6570\u7684\u63a7\u5236\u6d41\u7a0b\u5927\u81f4\u4e0e\u8bfb\u51fd\u6570\u76f8\u540c\uff0c\u53ea\u4e0d\u8fc7\u5bf9\u5e94\u7684\u7b49\u5f85\u961f\u5217\u662f\u5199\u7b49\u5f85\u961f\u5217\u3002<\/p>\n
ssize_t myblock_write(struct file*fp,char*buf,size_t count,loff_t*offp)\r\n{\r\n\tint ret;\r\n\tDECLARE_WAITQUEUE(wait,current);\r\n\r\n\tdown(&mutex);\r\n\tadd_wait_queue(&wrwait,&wait);\r\n\r\n\twhile(len==BUF_NUM)\r\n\t{\r\n\t\t__set_current_state(TASK_INTERRUPTIBLE);\r\n\t\tup(&mutex);\r\n\t\tschedule();\r\n\t\tif(signal_pending(current))\r\n\t\t{\r\n\t\t\tret=-1;\r\n\t\t\tgoto signal_out;\r\n\t\t}\r\n\r\n         \tdown(&mutex);\r\n\t}\r\n\tif(count>(BUF_NUM-len))\r\n\t{\r\n\t\tcount=BUF_NUM-len;\r\n\t}\r\n\r\n\tif(copy_from_user(globalmem+len,buf,count)==0)\r\n\t{\r\n\t\tlen=len+count;\r\n\t\tprintk(\"written %d bytes\\n\",count);\r\n\t\twake_up_interruptible(&rdwait);\r\n\t\tret=count;\r\n\t}\r\n\telse\r\n\t{\r\n\t\tret=-1;\r\n\t\tgoto COPY_ERR_OUT;\r\n\t}\r\n\r\nsignal_out:up(&mutex);\r\nCOPY_ERR_OUT:remove_wait_queue(&wrwait,&wait);\r\n\tset_current_state(TASK_RUNNING);\r\n\r\n\treturn ret;\r\n}<\/pre>\n
\u4e0a\u8ff0\u5c31\u662f\u652f\u6301\u963b\u585e\u6a21\u5f0f\u7684\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8\u3002\u5173\u4e8e\u4e0a\u8ff0\u7a0b\u5e8f\u66f4\u591a\u7684\u89e3\u91ca\u5982\u4e0b\uff1a<\/p>\n
1.\u4e24\u79cd\u7761\u7720\u3002\u5f53\u8bfb\u8fdb\u7a0b\u8bfb\u6570\u636e\u65f6\uff0c\u5982\u679c\u53d1\u73b0\u5199\u8fdb\u7a0b\u6b63\u5728\u8bbf\u95ee\u4e34\u754c\u533a\uff0c\u90a3\u4e48\u5b83\u4f1a\u56e0\u4e3a\u4e0d\u80fd\u83b7\u5f97\u4e92\u65a5\u4fe1\u53f7\u91cf\u800c\u963b\u585e\uff1b\u800c\u5f53\u8bfb\u8fdb\u7a0b\u83b7\u5f97\u4fe1\u53f7\u91cf\u540e\uff0c\u5982\u679c\u5f53\u524dglobalfifo\u7684\u6570\u636e\u6570\u4e3a0\uff0c\u5219\u4f1a\u963b\u585e\u3002\u8fd9\u79cd\u963b\u585e\u662f\u7531\u6211\u4eec\u5728\u8bbe\u5907\u9a71\u52a8\u4e2d\u5b9e\u73b0\u7684\u3002<\/p>\n
2.\u4e24\u79cd\u5524\u9192\u3002\u5f53\u5199\u8fdb\u7a0b\u79bb\u5f00\u4e34\u754c\u533a\u5e76\u91ca\u653e\u4fe1\u53f7\u91cf\u65f6\uff0c\u8bfb\u8fdb\u7a0b\u4f1a\u56e0\u4fe1\u53f7\u91cf\u88ab\u91ca\u653e\u800c\u5524\u9192\uff1b\u5f53\u5199\u8fdb\u7a0b\u5f80globalfifo\u4e2d\u5199\u5165\u4e86\u6570\u636e\u65f6\uff0c\u8bfb\u8fdb\u7a0b\u4f1a\u88ab\u5199\u8fdb\u7a0b\u4e2d\u7684\u5524\u9192\u51fd\u6570\u6240\u5524\u9192\u3002\u7279\u522b\u7684\uff0c\u5982\u679c\u8bfb\u8fdb\u7a0b\u662f\u4ee5\u8f7b\u5ea6\u7761\u7720\u65b9\u5f0f\u7761\u7720\u7684\uff0c\u90a3\u4e48\u7528\u6237\u53ef\u4ee5\u901a\u8fc7\u53d1\u9001\u4fe1\u53f7\u800c\u5524\u9192\u7761\u7720\u7684\u8bfb\u8fdb\u7a0b\u3002<\/p>\n
3.\u5524\u9192\u540e\u5982\u4f55\u6267\u884c\u3002\u65e0\u8bba\u56e0\u54ea\u79cd\u65b9\u5f0f\u800c\u7761\u7720\uff0c\u5f53\u8bfb\u8fdb\u7a0b\u88ab\u5524\u9192\u540e\uff0c\u5747\u987a\u5e8f\u6267\u884c\u63a5\u4e0b\u6765\u7684\u4ee3\u7801\u3002<\/p>\n
4.down\u64cd\u4f5c\u548cadd_wait_queue\u64cd\u4f5c\u4ea4\u6362\u3002\u5728\u539f\u7a0b\u5e8f\u4e2d\uff0c\u8bfb\u8fdb\u7a0b\u5148\u83b7\u53d6\u4fe1\u53f7\u91cf\uff0c\u518d\u5c06\u8bfb\u8fdb\u7a0b\u5bf9\u5e94\u7684\u7b49\u5f85\u961f\u5217\u9879\u6dfb\u52a0\u5230\u8bfb\u7b49\u5f85\u961f\u5217\u4e2d\u3002\u5982\u679c\u4ea4\u6362\uff0c\u5f53\u8bfb\u8fdb\u7a0b\u7684\u7b49\u5f85\u961f\u5217\u9879\u52a0\u5165\u5230\u7b49\u5f85\u961f\u5217\u540e\uff0c\u5b83\u53ef\u80fd\u53c8\u4f1a\u56e0\u672a\u83b7\u5f97\u4fe1\u53f7\u91cf\u800c\u963b\u585e\u3002<\/p>\n
5.up\u64cd\u4f5c\u548cremove_wait_queue\u64cd\u4f5c\u4ea4\u6362\u3002\u8fd9\u4e24\u4e2a\u64cd\u4f5c\u5206\u522b\u5bf9\u5e94\u6807\u53f7out\u548cout2\u3002\u5982\u679c\u8bfb\u8fdb\u7a0b\u4ece\u5185\u6838\u7a7a\u95f4\u5411\u7528\u6237\u7a7a\u95f4\u62f7\u8d1d\u6570\u636e\u5931\u8d25\u65f6\uff0c\u5c31\u4f1a\u8df3\u8f6c\u5230out\u3002\u56e0\u4e3a\u8bfb\u8fdb\u7a0b\u662f\u5728\u83b7\u5f97\u4fe1\u53f7\u91cf\u540e\u624d\u62f7\u8d1d\u6570\u636e\u7684\uff0c\u56e0\u6b64\u5fc5\u987b\u5148\u91ca\u653e\u4fe1\u53f7\u91cf\uff0c\u518d\u5c06\u8bfb\u8fdb\u7a0b\u5bf9\u5e94\u7684\u7b49\u5f85\u961f\u5217\u9879\u79fb\u51fa\u8bfb\u7b49\u5f85\u961f\u5217\u3002\u800c\u5f53\u8bfb\u8fdb\u7a0b\u56e0\u4fe1\u53f7\u800c\u88ab\u5524\u9192\u65f6\uff0c\u5219\u76f4\u63a5\u8df3\u8f6c\u5230out2\u3002\u6b64\u65f6\u8bfb\u8fdb\u7a0b\u5e76\u6ca1\u6709\u83b7\u5f97\u4fe1\u53f7\u91cf\uff0c\u56e0\u6b64\u53ea\u9700\u8981\u79fb\u51fa\u961f\u5217\u64cd\u4f5c\u5373\u53ef\u3002\u5982\u679c\u4ea4\u6362\u4e0a\u8ff0\u4e24\u4e2a\u64cd\u4f5c\uff0c\u8bfb\u8fdb\u7a0b\u79fb\u51fa\u7b49\u5f85\u961f\u5217\u65f6\u8fd8\u672a\u91ca\u653e\u4e92\u65a5\u4fe1\u53f7\u91cf\uff0c\u90a3\u4e48\u5199\u8fdb\u7a0b\u5c31\u4e0d\u80fd\u5199\u3002\u800c\u5f53\u8bfb\u8fdb\u7a0b\u56e0\u4fe1\u53f7\u800c\u5524\u9192\u65f6\uff0c\u8bfb\u8fdb\u7a0b\u5e76\u6ca1\u6709\u83b7\u5f97\u4fe1\u53f7\u91cf\uff0c\u5374\u8fd8\u8981\u91ca\u653e\u4fe1\u53f7\u91cf\u3002<\/p>\n
\u901a\u8fc7\u4e0b\u8ff0\u65b9\u6cd5\uff0c\u4f60\u5c31\u53ef\u4ee5\u4f53\u9a8c\u5230\u4ee5\u963b\u585e\u65b9\u5f0f\u8bbf\u95ee\u8bbe\u5907\u6587\u4ef6\u3002<\/p>\n
1.make\u7f16\u8bd1\u6587\u4ef6\uff0c\u5e76\u63d2\u5165\u5230\u5185\u6838\uff1b
\n2.\u521b\u5efa\u8bbe\u5907\u6587\u4ef6\u7ed3\u70b9\uff1asudo mknod \/dev\/blockcdev c major_num 0\uff1b
\n3.\u4fee\u6539\u8bbe\u5907\u6587\u4ef6\u6743\u9650\uff1asudo chmod 777 \/dev\/blockcdev\uff1b
\n4.\u7ec8\u7aef\u8f93\u5165\uff1acat \/dev\/blockcdev&\uff1b\u5373\u4ece\u5b57\u7b26\u8bbe\u5907\u6587\u4ef6\u4e2d\u8bfb\u6570\u636e\uff0c\u5e76\u8ba9\u8fd9\u4e2a\u8bfb\u8fdb\u7a0b\u5728\u540e\u53f0\u6267\u884c\uff0c\u53ef\u901a\u8fc7ps\u547d\u4ee4\u67e5\u770b\u5230\u8fd9\u4e2a\u8fdb\u7a0b\uff1b
\n5.\u4e2d\u65ad\u7ee7\u7eed\u8f93\u5165\uff1aecho ‘I like eating..’ > \/dev\/blockcdev\uff1b\u5373\u5411\u5b57\u7b26\u8bbe\u5907\u6587\u4ef6\u4e2d\u5199\u5165\u6570\u636e\uff1b<\/em><\/strong><\/p>\n
<\/em><\/strong>\u901a\u8fc7\u4e0a\u8ff0\u7684\u6b65\u9aa4\uff0c\u53ef\u4ee5\u770b\u5230\uff0c\u6bcf\u5f53\u5229\u7528echo\u547d\u4ee4\u5199\u5165\u6570\u636e\u65f6\uff0c\u540e\u53f0\u8fd0\u884c\u7684\u8bfb\u8fdb\u7a0b\u5c31\u4f1a\u8bfb\u51fa\u6570\u636e\uff0c\u5426\u5219\u8bfb\u8fdb\u7a0b\u4e00\u76f4\u963b\u585e\u3002\u6b64\u5916\uff0c\u5982\u679c\u4f60\u613f\u610f\u7684\u8bdd\uff0c\u8fd8\u53ef\u4ee5\u5206\u522b\u7f16\u5199\u4e00\u4e2a\u8bfb\u5199\u8fdb\u7a0b\u7684\u7a0b\u5e8f\u8fdb\u884c\u6d4b\u8bd5\u3002<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"
\u5728\u524d\u6587\u4e2d\uff0c\u6211\u4eec\u5df2\u7ecf\u77e5\u9053\u4e86\u5982\u4f55\u7f16\u5199\u4e00\u4e2a\u7b80\u5355\u7684\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8\u3002\u672c\u6587\u5c06\u5728\u6b64\u57fa\u7840\u4e0a\u4e3a\u8fd9\u4e2a\u5b57\u7b26\u8bbe\u5907\u9a71\u52a8\u589e\u52a0\u963b\u585e\u529f\u80fd\u3002\u4e0d\u8fc7\u5728 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[146],"tags":[134,152,403],"class_list":["post-1895","post","type-post","status-publish","format-standard","hentry","category-146","tag-kernel","tag-152","tag-403"],"views":13732,"_links":{"self":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/1895","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/comments?post=1895"}],"version-history":[{"count":0,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/posts\/1895\/revisions"}],"wp:attachment":[{"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/media?parent=1895"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/categories?post=1895"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/edsionte.com\/techblog\/wp-json\/wp\/v2\/tags?post=1895"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}