[net/9p] Set the condition just before waking up. (a01a9840) · Commits · 戴 / test

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>

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);
		}

		/**

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