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Commit a01a9840 authored by Venkateswararao Jujjuri (JV)'s avatar Venkateswararao Jujjuri (JV) Committed by Eric Van Hensbergen
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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: default avatarVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
parent 53bda3e5

net/9p/trans_virtio.c

+22 −22
Original line number Diff line number Diff line
@@ -141,20 +141,22 @@ 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) {

		if (rc == NULL) {

			spin_unlock_irqrestore(&chan->lock, flags);

			break;

		}



		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);

		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 */
@@ -163,11 +165,9 @@ static void req_done(struct virtqueue *vq) 
				kfree(rp);

			req->tc->private = NULL;

		}

		req->status = REQ_STATUS_RCVD;

		p9_client_cb(chan->client, req);

		} else {

			spin_unlock_irqrestore(&chan->lock, flags);

	}

	} while (rc != NULL);

}



/**