在 2022/8/17 21:57, Guo Zhi 写道:
We didn't unmask F_NEXT flag in desc_extra in the end of a chain,
unmask it so that we can access desc_extra to get next information.
Signed-off-by: Guo Zhi <qtxuning1...@sjtu.edu.cn>
I post a similar patch in the past.
Please share the perf numbers (e.g pps via pktgen).
Thanks
---
drivers/virtio/virtio_ring.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index a5ec724c01d8..1c1b3fa376a2 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -567,7 +567,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
}
/* Last one doesn't continue. */
desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
- if (!indirect && vq->use_dma_api)
+ if (!indirect)
vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &=
~VRING_DESC_F_NEXT;
@@ -584,6 +584,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
total_sg * sizeof(struct vring_desc),
VRING_DESC_F_INDIRECT,
false);
+ vq->split.desc_extra[head & (vq->split.vring.num - 1)].flags &=
+ ~VRING_DESC_F_NEXT;
}
/* We're using some buffers from the free list. */
@@ -693,7 +695,7 @@ static void detach_buf_split(struct vring_virtqueue *vq,
unsigned int head,
/* Put back on free list: unmap first-level descriptors and find end */
i = head;
- while (vq->split.vring.desc[i].flags & nextflag) {
+ while (vq->split.desc_extra[i].flags & nextflag) {
vring_unmap_one_split(vq, i);
i = vq->split.desc_extra[i].next;
vq->vq.num_free++;
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