On Tue, Jan 16, 2024 at 3:59 PM Xuan Zhuo <xuanz...@linux.alibaba.com> wrote: > > Introduce helper virtqueue_get_dma_premapped(), then the driver > can know whether dma unmap is needed. > > Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com> > --- > drivers/net/virtio/main.c | 22 +++++++++------------- > drivers/net/virtio/virtio_net.h | 3 --- > drivers/virtio/virtio_ring.c | 22 ++++++++++++++++++++++ > include/linux/virtio.h | 1 + > 4 files changed, 32 insertions(+), 16 deletions(-) > > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c > index 186b2cf5d8fc..4fbf612da235 100644 > --- a/drivers/net/virtio/main.c > +++ b/drivers/net/virtio/main.c > @@ -483,7 +483,7 @@ static void *virtnet_rq_get_buf(struct virtnet_rq *rq, > u32 *len, void **ctx) > void *buf; > > buf = virtqueue_get_buf_ctx(rq->vq, len, ctx); > - if (buf && rq->do_dma) > + if (buf && virtqueue_get_dma_premapped(rq->vq)) > virtnet_rq_unmap(rq, buf, *len); > > return buf; > @@ -496,7 +496,7 @@ static void virtnet_rq_init_one_sg(struct virtnet_rq *rq, > void *buf, u32 len) > u32 offset; > void *head; > > - if (!rq->do_dma) { > + if (!virtqueue_get_dma_premapped(rq->vq)) { > sg_init_one(rq->sg, buf, len); > return; > } > @@ -526,7 +526,7 @@ static void *virtnet_rq_alloc(struct virtnet_rq *rq, u32 > size, gfp_t gfp) > > head = page_address(alloc_frag->page); > > - if (rq->do_dma) { > + if (virtqueue_get_dma_premapped(rq->vq)) { > dma = head; > > /* new pages */ > @@ -580,12 +580,8 @@ static void virtnet_rq_set_premapped(struct virtnet_info > *vi) > if (!vi->mergeable_rx_bufs && vi->big_packets) > return; > > - for (i = 0; i < vi->max_queue_pairs; i++) { > - if (virtqueue_set_dma_premapped(vi->rq[i].vq)) > - continue; > - > - vi->rq[i].do_dma = true; > - } > + for (i = 0; i < vi->max_queue_pairs; i++) > + virtqueue_set_dma_premapped(vi->rq[i].vq); > } > > static void free_old_xmit(struct virtnet_sq *sq, bool in_napi) > @@ -1643,7 +1639,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, > struct virtnet_rq *rq, > > err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp); > if (err < 0) { > - if (rq->do_dma) > + if (virtqueue_get_dma_premapped(rq->vq)) > virtnet_rq_unmap(rq, buf, 0); > put_page(virt_to_head_page(buf)); > } > @@ -1758,7 +1754,7 @@ static int add_recvbuf_mergeable(struct virtnet_info > *vi, > ctx = mergeable_len_to_ctx(len + room, headroom); > err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp); > if (err < 0) { > - if (rq->do_dma) > + if (virtqueue_get_dma_premapped(rq->vq)) > virtnet_rq_unmap(rq, buf, 0); > put_page(virt_to_head_page(buf)); > } > @@ -4007,7 +4003,7 @@ static void free_receive_page_frags(struct virtnet_info > *vi) > int i; > for (i = 0; i < vi->max_queue_pairs; i++) > if (vi->rq[i].alloc_frag.page) { > - if (vi->rq[i].do_dma && vi->rq[i].last_dma) > + if (virtqueue_get_dma_premapped(vi->rq[i].vq) && > vi->rq[i].last_dma) > virtnet_rq_unmap(&vi->rq[i], > vi->rq[i].last_dma, 0); > put_page(vi->rq[i].alloc_frag.page); > } > @@ -4035,7 +4031,7 @@ static void virtnet_rq_free_unused_bufs(struct > virtqueue *vq) > rq = &vi->rq[i]; > > while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) { > - if (rq->do_dma) > + if (virtqueue_get_dma_premapped(rq->vq)) > virtnet_rq_unmap(rq, buf, 0); > > virtnet_rq_free_buf(vi, rq, buf); > diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h > index b28a4d0a3150..066a2b9d2b3c 100644 > --- a/drivers/net/virtio/virtio_net.h > +++ b/drivers/net/virtio/virtio_net.h > @@ -115,9 +115,6 @@ struct virtnet_rq { > > /* Record the last dma info to free after new pages is allocated. */ > struct virtnet_rq_dma *last_dma; > - > - /* Do dma by self */ > - bool do_dma; > }; > > struct virtnet_info { > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 2c5089d3b510..9092bcdebb53 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -2905,6 +2905,28 @@ int virtqueue_set_dma_premapped(struct virtqueue *_vq) > } > EXPORT_SYMBOL_GPL(virtqueue_set_dma_premapped); > > +/** > + * virtqueue_get_dma_premapped - get the vring premapped mode > + * @_vq: the struct virtqueue we're talking about. > + * > + * Get the premapped mode of the vq. > + * > + * Returns bool for the vq premapped mode. > + */ > +bool virtqueue_get_dma_premapped(struct virtqueue *_vq) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + bool premapped; > + > + START_USE(vq); > + premapped = vq->premapped; > + END_USE(vq);
Why do we need to protect premapped like this? Is the user allowed to change it on the fly? Thanks