From 5720c43d5216b5dbd9ab25595f7c61e55d36d4fc Mon Sep 17 00:00:00 2001 From: Xuan Zhuo Date: Wed, 27 Sep 2023 13:52:46 +0800 Subject: [PATCH] virtio_net: fix the missing of the dma cpu sync Commit 295525e29a5b ("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: 295525e29a5b ("virtio_net: merge dma operations when filling mergeable buffers") Reported-by: Michael Roth Closes: http://lore.kernel.org/all/20230926130451.axgodaa6tvwqs3ut@amd.com Signed-off-by: Xuan Zhuo Acked-by: Jason Wang Signed-off-by: Linus Torvalds --- drivers/net/virtio_net.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index fe7f314..d67f742 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -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)); + 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); -- 2.7.4