---

yaml --- r: 331412 b: refs/heads/master c: d78b519 h: refs/heads/master v: v3
git-mirror · Sep 28, 2012 · 364f820 · 364f820
1 parent ea89813
commit 364f820
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Showing 2 changed files with 11 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3850d29fc40f3494a3e9c3aac45b6afe53526449
+refs/heads/master: d78b519f6b945aef6202bbb5b56f928572e15165
diff --git a/trunk/drivers/virtio/virtio_mmio.c b/trunk/drivers/virtio/virtio_mmio.c
@@ -331,6 +331,16 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
 	 * and two rings (which makes it "alignment_size * 2")
 	 */
 	info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
+
+	/* If the device reports a 0 entry queue, we won't be able to
+	 * use it to perform I/O, and vring_new_virtqueue() can't create
+	 * empty queues anyway, so don't bother to set up the device.
+	 */
+	if (info->num == 0) {
+		err = -ENOENT;
+		goto error_alloc_pages;
+	}
+
 	while (1) {
 		size = PAGE_ALIGN(vring_size(info->num,
 				VIRTIO_MMIO_VRING_ALIGN));