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authorRichard W.M. Jones <rjones@redhat.com>2017-08-10 17:56:51 +0100
committerMartin K. Petersen <martin.petersen@oracle.com>2017-08-24 22:28:51 -0400
commit44ed8089e991a60d614abe0ee4b9057a28b364e4 (patch)
treef44db9181e333dcf02dd3a2c8b5e233337825326
parent42d7c10f23786ed8521338ba6fd905a2459fa1e0 (diff)
downloadlwn-44ed8089e991a60d614abe0ee4b9057a28b364e4.tar.gz
lwn-44ed8089e991a60d614abe0ee4b9057a28b364e4.zip
scsi: virtio: Reduce BUG if total_sg > virtqueue size to WARN.
If using indirect descriptors, you can make the total_sg as large as you want. If not, BUG is too serious because the function later returns -ENOSPC. Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
-rw-r--r--drivers/virtio/virtio_ring.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 5e1b548828e6..27cbc1eab868 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -296,7 +296,6 @@ static inline int virtqueue_add(struct virtqueue *_vq,
}
#endif
- BUG_ON(total_sg > vq->vring.num);
BUG_ON(total_sg == 0);
head = vq->free_head;
@@ -305,8 +304,10 @@ static inline int virtqueue_add(struct virtqueue *_vq,
* buffers, then go indirect. FIXME: tune this threshold */
if (vq->indirect && total_sg > 1 && vq->vq.num_free)
desc = alloc_indirect(_vq, total_sg, gfp);
- else
+ else {
desc = NULL;
+ WARN_ON_ONCE(total_sg > vq->vring.num && !vq->indirect);
+ }
if (desc) {
/* Use a single buffer which doesn't continue */