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Track in buf if disk "owns" buffer

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This commit is contained in:
Frans Kaashoek 2019-07-30 12:53:19 -04:00
parent 87183da13d
commit 848d1906e8
2 changed files with 5 additions and 3 deletions
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1
kernel/buf.h
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@ -1,5 +1,6 @@
struct buf { struct buf {
int valid; // has data been read from disk? int valid; // has data been read from disk?
int disk; // does disk "own" buf?
uint dev; uint dev;
uint blockno; uint blockno;
struct sleeplock lock; struct sleeplock lock;

5
kernel/virtio_disk.c
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@ -222,6 +222,7 @@ virtio_disk_rw(struct buf *b, int write)
desc[idx[2]].next = 0; desc[idx[2]].next = 0;
// record struct buf for virtio_disk_intr(). // record struct buf for virtio_disk_intr().
b->disk = 1;
info[idx[0]].b = b; info[idx[0]].b = b;
// avail[0] is flags // avail[0] is flags
@ -235,7 +236,7 @@ virtio_disk_rw(struct buf *b, int write)
*R(VIRTIO_MMIO_QUEUE_NOTIFY) = 0; // value is queue number *R(VIRTIO_MMIO_QUEUE_NOTIFY) = 0; // value is queue number
// Wait for virtio_disk_intr() to say request has finished. // Wait for virtio_disk_intr() to say request has finished.
while(info[idx[0]].status == 0) { while(b->disk == 1) {
sleep(b, &vdisk_lock); sleep(b, &vdisk_lock);
} }
@ -256,7 +257,7 @@ virtio_disk_intr()
if(info[id].status != 0) if(info[id].status != 0)
panic("virtio_disk_intr status"); panic("virtio_disk_intr status");
info[id].status = 1; info[id].b->disk = 0; // disk is done with buf
wakeup(info[id].b); wakeup(info[id].b);
used_idx = (used_idx + 1) % NUM; used_idx = (used_idx + 1) % NUM;