On Thu, 25 Jan 2024 11:39:03 +0800, Jason Wang <jasow...@redhat.com> wrote: > 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?
Just protect before accessing vq. Thanks. > > Thanks >