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| author | Venkateswararao Jujjuri (JV) <jvrao@linux.vnet.ibm.com> | 2011-03-14 14:12:49 -0700 |
|---|---|---|
| committer | Eric Van Hensbergen <ericvh@gmail.com> | 2011-03-22 16:32:47 -0500 |
| commit | a01a984035ea799b14aa5e874dcaeb122f09c4b4 (patch) | |
| tree | 7998ac0aab9c53c25dde38710a4ab60ac7d2935f /net/9p | |
| parent | 53bda3e5b4e91763224ecb7d05dab94d281fd41d (diff) | |
| download | lwn-a01a984035ea799b14aa5e874dcaeb122f09c4b4.tar.gz lwn-a01a984035ea799b14aa5e874dcaeb122f09c4b4.zip | |
[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>
Diffstat (limited to 'net/9p')
| -rw-r--r-- | net/9p/trans_virtio.c | 44 |
1 files changed, 22 insertions, 22 deletions
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 961e025957ae..cb98af9367ab 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -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); + } } /** |