Commit 5720c43d authored by Xuan Zhuo's avatar Xuan Zhuo Committed by Linus Torvalds
Browse files

virtio_net: fix the missing of the dma cpu sync 



Commit 295525e2 ("virtio_net: merge dma operations when filling
mergeable buffers") unmaps the buffer with DMA_ATTR_SKIP_CPU_SYNC when
the dma->ref is zero. We do that with DMA_ATTR_SKIP_CPU_SYNC, because we
do not want to do the sync for the entire page_frag. But that misses the
sync for the current area.

This patch does cpu sync regardless of whether the ref is zero or not.

Fixes: 295525e2 ("virtio_net: merge dma operations when filling mergeable buffers")
Reported-by: default avatarMichael Roth <michael.roth@amd.com>
Closes: http://lore.kernel.org/all/20230926130451.axgodaa6tvwqs3ut@amd.com


Signed-off-by: default avatarXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 11d3f726

drivers/net/virtio_net.c

+7 −7
Original line number Diff line number Diff line
@@ -607,16 +607,16 @@ static void virtnet_rq_unmap(struct receive_queue *rq, void *buf, u32 len) 


	--dma->ref;



	if (dma->ref) {

	if (dma->need_sync && len) {

		offset = buf - (head + sizeof(*dma));



			virtqueue_dma_sync_single_range_for_cpu(rq->vq, dma->addr, offset,

								len, DMA_FROM_DEVICE);

		virtqueue_dma_sync_single_range_for_cpu(rq->vq, dma->addr,

							offset, len,

							DMA_FROM_DEVICE);

	}



	if (dma->ref)

		return;

	}



	virtqueue_dma_unmap_single_attrs(rq->vq, dma->addr, dma->len,

					 DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);