Remove B_DIRTY

Use refcnt to pin blocks into the cache
Replace flags/B_VALID with a boolean field valid
Use info[id].status to signal completion of disk interrupt
Pass a read/write flag to virtio_disk_rw

1 files changed, 5 insertions, 7 deletions

diff --git a/kernel/virtio_disk.c b/kernel/virtio_disk.c
index 3ace5ef..df4473d 100644
--- a/kernel/virtio_disk.c
+++ b/kernel/virtio_disk.c
@@ -164,7 +164,7 @@ alloc3_desc(int *idx)
 }
 
 void
-virtio_disk_rw(struct buf *b)
+virtio_disk_rw(struct buf *b, int write)
 {
   uint64 sector = b->blockno * (BSIZE / 512);
 
@@ -192,7 +192,7 @@ virtio_disk_rw(struct buf *b)
     uint64 sector;
   } buf0;
 
-  if(b->flags & B_DIRTY)
+  if(write)
     buf0.type = VIRTIO_BLK_T_OUT; // write the disk
   else
     buf0.type = VIRTIO_BLK_T_IN; // read the disk
@@ -208,7 +208,7 @@ virtio_disk_rw(struct buf *b)
 
   desc[idx[1]].addr = (uint64) b->data;
   desc[idx[1]].len = BSIZE;
-  if(b->flags & B_DIRTY)
+  if(write)
     desc[idx[1]].flags = 0; // device reads b->data
   else
     desc[idx[1]].flags = VRING_DESC_F_WRITE; // device writes b->data
@@ -235,7 +235,7 @@ virtio_disk_rw(struct buf *b)
   *R(VIRTIO_MMIO_QUEUE_NOTIFY) = 0; // value is queue number
 
   // Wait for virtio_disk_intr() to say request has finished.
-  while((b->flags & (B_VALID|B_DIRTY)) != B_VALID){
+  while(info[idx[0]].status == 0) {
     sleep(b, &vdisk_lock);
   }
 
@@ -253,9 +253,7 @@ virtio_disk_intr()
     if(info[id].status != 0)
       panic("virtio_disk_intr status");
 
-    info[id].b->flags |= B_VALID;
-    info[id].b->flags &= ~B_DIRTY;
-
+    info[id].status = 1;
     wakeup(info[id].b);
 
     info[id].b = 0;