Xuan Zhuo
2023-Sep-27 05:52 UTC
[PATCH vhost] 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 <michael.roth at amd.com>
Closes: http://lore.kernel.org/all/20230926130451.axgodaa6tvwqs3ut at amd.com
Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
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 98dc9b49d56b..9ece27dc5144 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -589,16 +589,16 @@ 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);
--
2.32.0.3.g01195cf9f
Jason Wang
2023-Oct-08 04:53 UTC
[PATCH vhost] virtio_net: fix the missing of the dma cpu sync
On Wed, Sep 27, 2023 at 1:53?PM Xuan Zhuo <xuanzhuo at linux.alibaba.com> wrote:> > 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 <michael.roth at amd.com> > Closes: http://lore.kernel.org/all/20230926130451.axgodaa6tvwqs3ut at amd.com > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>Acked-by: Jason Wang <jasowang at redhat.com> Thanks> --- > 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 98dc9b49d56b..9ece27dc5144 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -589,16 +589,16 @@ 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); > -- > 2.32.0.3.g01195cf9f > >