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[net/9p] Set the condition just before waking up. 

Given that the sprious wake-ups are common, we need to move the
condition setting right next to the wake_up().  After setting the condition
to req->status = REQ_STATUS_RCVD, sprious wakeups may cause the
virtqueue back on the free list for someone else to use.
This may result in kernel panic while relasing the pinned pages
in p9_release_req_pages().

Also rearranged the while loop in req_done() for better redability.

Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
This commit is contained in:
Venkateswararao Jujjuri (JV) 2011-03-14 14:12:49 -07:00 committed by Eric Van Hensbergen
parent 53bda3e5b4
commit a01a984035
1 changed files with 22 additions and 22 deletions
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44
net/9p/trans_virtio.c
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@ -141,33 +141,33 @@ static void req_done(struct virtqueue *vq)
P9_DPRINTK(P9_DEBUG_TRANS, ": request done\n");
do {
while (1) {
spin_lock_irqsave(&chan->lock, flags);
rc = virtqueue_get_buf(chan->vq, &len);
if (rc != NULL) {
chan->ring_bufs_avail = 1;
spin_unlock_irqrestore(&chan->lock, flags);
/* Wakeup if anyone waiting for VirtIO ring space. */
wake_up(chan->vc_wq);
P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc);
P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n",
rc->tag);
req = p9_tag_lookup(chan->client, rc->tag);
req->status = REQ_STATUS_RCVD;
if (req->tc->private) {
struct trans_rpage_info *rp = req->tc->private;
/*Release pages */
p9_release_req_pages(rp);
if (rp->rp_alloc)
kfree(rp);
req->tc->private = NULL;
}
p9_client_cb(chan->client, req);
} else {
if (rc == NULL) {
spin_unlock_irqrestore(&chan->lock, flags);
break;
}
} while (rc != NULL);
chan->ring_bufs_avail = 1;
spin_unlock_irqrestore(&chan->lock, flags);
/* Wakeup if anyone waiting for VirtIO ring space. */
wake_up(chan->vc_wq);
P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc);
P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag);
req = p9_tag_lookup(chan->client, rc->tag);
if (req->tc->private) {
struct trans_rpage_info *rp = req->tc->private;
/*Release pages */
p9_release_req_pages(rp);
if (rp->rp_alloc)
kfree(rp);
req->tc->private = NULL;
}
req->status = REQ_STATUS_RCVD;
p9_client_cb(chan->client, req);
}
}
/**