📄 blk.h
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<!doctype html public "-//W3C//DTD HTML 3.2//EN"><html><head><title>Linux/kernel/blk_drv/blk.h</title><meta http-equiv=Content-Type content="text/html; charset=gb2312"><base href="http://oldlinux.org/lxr/http/"></head><body bgcolor=white><div align=center> [<b><i>源代码浏览</i></b>] [<a href="diff/kernel/blk_drv/blk.h">区别标定</a>] [<a href="ident">标识符搜索</a>] [<a href="search">文本搜索</a>] [<a href="find">文件搜索</a>]</div><h1 align=center> <a href="http:/"> OldLinux</a> <a href="http:blurb.html"> 交叉引用</a><br> <a href="source/">Linux</a>/<a href="source/kernel/">kernel</a>/<a href="source/kernel/blk_drv/">blk_drv</a>/<a href="source/kernel/blk_drv/blk.h">blk.h</a></h1><div align=center> <b>版本:</b> [<a href="source/kernel/blk_drv/blk.h?v=1.0">1.0</a>] [<a href="source/kernel/blk_drv/blk.h?v=0.99.11">0.99.11</a>] [<a href="source/kernel/blk_drv/blk.h?v=0.99">0.99</a>] [<a href="source/kernel/blk_drv/blk.h?v=0.97">0.97</a>] [<a href="source/kernel/blk_drv/blk.h?v=0.96a">0.96a</a>] [<a href="source/kernel/blk_drv/blk.h?v=0.95">0.95</a>] [<a href="source/kernel/blk_drv/blk.h?v=0.12">0.12</a>] [<b><i>0.11</i></b>] [<a href="source/kernel/blk_drv/blk.h?v=0.01">0.01</a>] <br> <b>体系结构:</b> [<b><i>i386</i></b>] <br></div><hr><pre> <a name=L1 href="source/kernel/blk_drv/blk.h#L1">1</a> #ifndef <a href="ident?i=_BLK_H">_BLK_H</a> <a name=L2 href="source/kernel/blk_drv/blk.h#L2">2</a> #define <a href="ident?i=_BLK_H">_BLK_H</a> <a name=L3 href="source/kernel/blk_drv/blk.h#L3">3</a> <a name=L4 href="source/kernel/blk_drv/blk.h#L4">4</a> #define <a href="ident?i=NR_BLK_DEV">NR_BLK_DEV</a> 7 <a name=L5 href="source/kernel/blk_drv/blk.h#L5">5</a> <b><i>/*</i></b> <a name=L6 href="source/kernel/blk_drv/blk.h#L6">6</a> <b><i> * NR_REQUEST is the number of entries in the request-queue.</i></b> <a name=L7 href="source/kernel/blk_drv/blk.h#L7">7</a> <b><i> * NOTE that writes may use only the low 2/3 of these: reads</i></b> <a name=L8 href="source/kernel/blk_drv/blk.h#L8">8</a> <b><i> * take precedence.</i></b> <a name=L9 href="source/kernel/blk_drv/blk.h#L9">9</a> <b><i> *</i></b> <a name=L10 href="source/kernel/blk_drv/blk.h#L10">10</a> <b><i> * 32 seems to be a reasonable number: enough to get some benefit</i></b> <a name=L11 href="source/kernel/blk_drv/blk.h#L11">11</a> <b><i> * from the elevator-mechanism, but not so much as to lock a lot of</i></b> <a name=L12 href="source/kernel/blk_drv/blk.h#L12">12</a> <b><i> * buffers when they are in the queue. 64 seems to be too many (easily</i></b> <a name=L13 href="source/kernel/blk_drv/blk.h#L13">13</a> <b><i> * long pauses in reading when heavy writing/syncing is going on)</i></b> <a name=L14 href="source/kernel/blk_drv/blk.h#L14">14</a> <b><i> */</i></b> <a name=L15 href="source/kernel/blk_drv/blk.h#L15">15</a> #define <a href="ident?i=NR_REQUEST">NR_REQUEST</a> 32 <a name=L16 href="source/kernel/blk_drv/blk.h#L16">16</a> <a name=L17 href="source/kernel/blk_drv/blk.h#L17">17</a> <b><i>/*</i></b> <a name=L18 href="source/kernel/blk_drv/blk.h#L18">18</a> <b><i> * Ok, this is an expanded form so that we can use the same</i></b> <a name=L19 href="source/kernel/blk_drv/blk.h#L19">19</a> <b><i> * request for paging requests when that is implemented. In</i></b> <a name=L20 href="source/kernel/blk_drv/blk.h#L20">20</a> <b><i> * paging, 'bh' is NULL, and 'waiting' is used to wait for</i></b> <a name=L21 href="source/kernel/blk_drv/blk.h#L21">21</a> <b><i> * read/write completion.</i></b> <a name=L22 href="source/kernel/blk_drv/blk.h#L22">22</a> <b><i> */</i></b> <a name=L23 href="source/kernel/blk_drv/blk.h#L23">23</a> struct <a href="ident?i=request">request</a> { <a name=L24 href="source/kernel/blk_drv/blk.h#L24">24</a> int dev; <b><i>/* -1 if no request */</i></b> <a name=L25 href="source/kernel/blk_drv/blk.h#L25">25</a> int cmd; <b><i>/* READ or WRITE */</i></b> <a name=L26 href="source/kernel/blk_drv/blk.h#L26">26</a> int errors; <a name=L27 href="source/kernel/blk_drv/blk.h#L27">27</a> unsigned long <a href="ident?i=sector">sector</a>; <a name=L28 href="source/kernel/blk_drv/blk.h#L28">28</a> unsigned long nr_sectors; <a name=L29 href="source/kernel/blk_drv/blk.h#L29">29</a> char * buffer; <a name=L30 href="source/kernel/blk_drv/blk.h#L30">30</a> struct <a href="ident?i=task_struct">task_struct</a> * waiting; <a name=L31 href="source/kernel/blk_drv/blk.h#L31">31</a> struct <a href="ident?i=buffer_head">buffer_head</a> * bh; <a name=L32 href="source/kernel/blk_drv/blk.h#L32">32</a> struct <a href="ident?i=request">request</a> * next; <a name=L33 href="source/kernel/blk_drv/blk.h#L33">33</a> }; <a name=L34 href="source/kernel/blk_drv/blk.h#L34">34</a> <a name=L35 href="source/kernel/blk_drv/blk.h#L35">35</a> <b><i>/*</i></b> <a name=L36 href="source/kernel/blk_drv/blk.h#L36">36</a> <b><i> * This is used in the elevator algorithm: Note that</i></b> <a name=L37 href="source/kernel/blk_drv/blk.h#L37">37</a> <b><i> * reads always go before writes. This is natural: reads</i></b> <a name=L38 href="source/kernel/blk_drv/blk.h#L38">38</a> <b><i> * are much more time-critical than writes.</i></b> <a name=L39 href="source/kernel/blk_drv/blk.h#L39">39</a> <b><i> */</i></b> <a name=L40 href="source/kernel/blk_drv/blk.h#L40">40</a> #define <a href="ident?i=IN_ORDER">IN_ORDER</a>(s1,s2) \ <a name=L41 href="source/kernel/blk_drv/blk.h#L41">41</a> ((s1)->cmd<(s2)->cmd || (s1)->cmd==(s2)->cmd && \ <a name=L42 href="source/kernel/blk_drv/blk.h#L42">42</a> ((s1)->dev < (s2)->dev || ((s1)->dev == (s2)->dev && \ <a name=L43 href="source/kernel/blk_drv/blk.h#L43">43</a> (s1)-><a href="ident?i=sector">sector</a> < (s2)-><a href="ident?i=sector">sector</a>))) <a name=L44 href="source/kernel/blk_drv/blk.h#L44">44</a> <a name=L45 href="source/kernel/blk_drv/blk.h#L45">45</a> struct <a href="ident?i=blk_dev_struct">blk_dev_struct</a> { <a name=L46 href="source/kernel/blk_drv/blk.h#L46">46</a> void (*request_fn)(void); <a name=L47 href="source/kernel/blk_drv/blk.h#L47">47</a> struct <a href="ident?i=request">request</a> * current_request; <a name=L48 href="source/kernel/blk_drv/blk.h#L48">48</a> }; <a name=L49 href="source/kernel/blk_drv/blk.h#L49">49</a> <a name=L50 href="source/kernel/blk_drv/blk.h#L50">50</a> extern struct <a href="ident?i=blk_dev_struct">blk_dev_struct</a> <a href="ident?i=blk_dev">blk_dev</a>[<a href="ident?i=NR_BLK_DEV">NR_BLK_DEV</a>]; <a name=L51 href="source/kernel/blk_drv/blk.h#L51">51</a> extern struct <a href="ident?i=request">request</a> <a href="ident?i=request">request</a>[<a href="ident?i=NR_REQUEST">NR_REQUEST</a>]; <a name=L52 href="source/kernel/blk_drv/blk.h#L52">52</a> extern struct <a href="ident?i=task_struct">task_struct</a> * <a href="ident?i=wait_for_request">wait_for_request</a>; <a name=L53 href="source/kernel/blk_drv/blk.h#L53">53</a> <a name=L54 href="source/kernel/blk_drv/blk.h#L54">54</a> #ifdef <a href="ident?i=MAJOR_NR">MAJOR_NR</a> <a name=L55 href="source/kernel/blk_drv/blk.h#L55">55</a> <a name=L56 href="source/kernel/blk_drv/blk.h#L56">56</a> <b><i>/*</i></b> <a name=L57 href="source/kernel/blk_drv/blk.h#L57">57</a> <b><i> * Add entries as needed. Currently the only block devices</i></b> <a name=L58 href="source/kernel/blk_drv/blk.h#L58">58</a> <b><i> * supported are hard-disks and floppies.</i></b> <a name=L59 href="source/kernel/blk_drv/blk.h#L59">59</a> <b><i> */</i></b> <a name=L60 href="source/kernel/blk_drv/blk.h#L60">60</a> ⌨️ 快捷键说明
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