code:notavil - ikarishinjieva/unixV6-code-analyze-chs GitHub Wiki

4995

4996 /* Unlink a buffer from the available list and mark it busy.

4997  * (internal interface)

4998  */

4999 notavil(bp)

5000 struct buf *bp;

5001 {

5002     register struct buf *rbp;

5003     register int sps;

5004

5005     rbp = bp;

5006     sps = PS->integ;

• 将PS备份到sps

5007     spl6();

• 处理机优级设为6

5008     rbp->av_back->av_forw = rbp->av_forw;

5009     rbp->av_forw->av_back = rbp->av_back;

5010     rbp->b_flags =| B_BUSY;

• 将给定的 缓存管理结构 从自由队列取下
• 置该块状态为B_BUSY

5011     PS->integ = sps;

• 从sps还原PS
• 还原PS 相当于 开中断

5012 }

5013 /* ------------------------- */

• 设备缓存管理

• code:getblk
• code:bflush