Messages in this thread Patch in this message | | | From | "Richard W.M. Jones" <> | Subject | [PATCH v2 1/2] virtio: Reduce BUG if total_sg > virtqueue size to WARN. | Date | Thu, 10 Aug 2017 17:56:51 +0100 |
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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.
Thanks Paolo Bonzini, Christoph Hellwig.
Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> --- drivers/virtio/virtio_ring.c | 5 +++-- 1 file 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 */ -- 2.13.1
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