Jason Wang
2023-Jun-28 04:07 UTC
[PATCH vhost v10 03/10] virtio_ring: split: support add premapped buf
On Tue, Jun 27, 2023 at 5:05?PM Xuan Zhuo <xuanzhuo at linux.alibaba.com> wrote:> > On Tue, 27 Jun 2023 16:03:26 +0800, Jason Wang <jasowang at redhat.com> wrote: > > On Fri, Jun 2, 2023 at 5:22?PM Xuan Zhuo <xuanzhuo at linux.alibaba.com> wrote: > > > > > > If the vq is the premapped mode, use the sg_dma_address() directly. > > > > > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > > > --- > > > drivers/virtio/virtio_ring.c | 46 ++++++++++++++++++++++-------------- > > > 1 file changed, 28 insertions(+), 18 deletions(-) > > > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > > index 2afdfb9e3e30..18212c3e056b 100644 > > > --- a/drivers/virtio/virtio_ring.c > > > +++ b/drivers/virtio/virtio_ring.c > > > @@ -598,8 +598,12 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > > for (sg = sgs[n]; sg; sg = sg_next(sg)) { > > > dma_addr_t addr; > > > > > > - if (vring_map_one_sg(vq, sg, DMA_TO_DEVICE, &addr)) > > > - goto unmap_release; > > > + if (vq->premapped) { > > > + addr = sg_dma_address(sg); > > > + } else { > > > + if (vring_map_one_sg(vq, sg, DMA_TO_DEVICE, &addr)) > > > + goto unmap_release; > > > + } > > > > Btw, I wonder whether or not it would be simple to implement the > > vq->premapped check inside vring_map_one_sg() assuming the > > !use_dma_api is done there as well. > > > YES, > > That will more simple for the caller. > > But we will have things like: > > int func(bool do) > { > if (!do) > return; > } > > I like this way, but you don't like it in last version.I see :) So I think it depends on the error handling path, we should choose a way that can let us easily deal with errors. For example, it seems the current approach is better since it doesn't need to change the unmap_release. Thanks> > > > > > > > > prev = i; > > > /* Note that we trust indirect descriptor > > > @@ -614,8 +618,12 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > > for (sg = sgs[n]; sg; sg = sg_next(sg)) { > > > dma_addr_t addr; > > > > > > - if (vring_map_one_sg(vq, sg, DMA_FROM_DEVICE, &addr)) > > > - goto unmap_release; > > > + if (vq->premapped) { > > > + addr = sg_dma_address(sg); > > > + } else { > > > + if (vring_map_one_sg(vq, sg, DMA_FROM_DEVICE, &addr)) > > > + goto unmap_release; > > > + } > > > > > > prev = i; > > > /* Note that we trust indirect descriptor > > > @@ -689,21 +697,23 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > > return 0; > > > > > > unmap_release: > > > - err_idx = i; > > > + if (!vq->premapped) { > > > > Can vq->premapped be true here? The label is named as "unmap_relase" > > which implies "map" beforehand which seems not the case for > > premapping. > > I see. > > Rethink about this, there is a better way. > I will fix in next version. > > > Thanks. > > > > > > Thanks > > > > > > > + err_idx = i; > > > > > > - if (indirect) > > > - i = 0; > > > - else > > > - i = head; > > > - > > > - for (n = 0; n < total_sg; n++) { > > > - if (i == err_idx) > > > - break; > > > - if (indirect) { > > > - vring_unmap_one_split_indirect(vq, &desc[i]); > > > - i = virtio16_to_cpu(_vq->vdev, desc[i].next); > > > - } else > > > - i = vring_unmap_one_split(vq, i); > > > + if (indirect) > > > + i = 0; > > > + else > > > + i = head; > > > + > > > + for (n = 0; n < total_sg; n++) { > > > + if (i == err_idx) > > > + break; > > > + if (indirect) { > > > + vring_unmap_one_split_indirect(vq, &desc[i]); > > > + i = virtio16_to_cpu(_vq->vdev, desc[i].next); > > > + } else > > > + i = vring_unmap_one_split(vq, i); > > > + } > > > } > > > > > > if (indirect) > > > -- > > > 2.32.0.3.g01195cf9f > > > > > >
Xuan Zhuo
2023-Jun-28 06:00 UTC
[PATCH vhost v10 03/10] virtio_ring: split: support add premapped buf
On Wed, 28 Jun 2023 12:07:10 +0800, Jason Wang <jasowang at redhat.com> wrote:> On Tue, Jun 27, 2023 at 5:05?PM Xuan Zhuo <xuanzhuo at linux.alibaba.com> wrote: > > > > On Tue, 27 Jun 2023 16:03:26 +0800, Jason Wang <jasowang at redhat.com> wrote: > > > On Fri, Jun 2, 2023 at 5:22?PM Xuan Zhuo <xuanzhuo at linux.alibaba.com> wrote: > > > > > > > > If the vq is the premapped mode, use the sg_dma_address() directly. > > > > > > > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > > > > --- > > > > drivers/virtio/virtio_ring.c | 46 ++++++++++++++++++++++-------------- > > > > 1 file changed, 28 insertions(+), 18 deletions(-) > > > > > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > > > index 2afdfb9e3e30..18212c3e056b 100644 > > > > --- a/drivers/virtio/virtio_ring.c > > > > +++ b/drivers/virtio/virtio_ring.c > > > > @@ -598,8 +598,12 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > > > for (sg = sgs[n]; sg; sg = sg_next(sg)) { > > > > dma_addr_t addr; > > > > > > > > - if (vring_map_one_sg(vq, sg, DMA_TO_DEVICE, &addr)) > > > > - goto unmap_release; > > > > + if (vq->premapped) { > > > > + addr = sg_dma_address(sg); > > > > + } else { > > > > + if (vring_map_one_sg(vq, sg, DMA_TO_DEVICE, &addr)) > > > > + goto unmap_release; > > > > + } > > > > > > Btw, I wonder whether or not it would be simple to implement the > > > vq->premapped check inside vring_map_one_sg() assuming the > > > !use_dma_api is done there as well. > > > > > > YES, > > > > That will more simple for the caller. > > > > But we will have things like: > > > > int func(bool do) > > { > > if (!do) > > return; > > } > > > > I like this way, but you don't like it in last version. > > I see :) > > So I think it depends on the error handling path, we should choose a > way that can let us easily deal with errors. > > For example, it seems the current approach is better since it doesn't > need to change the unmap_release.NO, The unmap_release is same for two way. Thanks.> > Thanks > > > > > > > > > > > > > > prev = i; > > > > /* Note that we trust indirect descriptor > > > > @@ -614,8 +618,12 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > > > for (sg = sgs[n]; sg; sg = sg_next(sg)) { > > > > dma_addr_t addr; > > > > > > > > - if (vring_map_one_sg(vq, sg, DMA_FROM_DEVICE, &addr)) > > > > - goto unmap_release; > > > > + if (vq->premapped) { > > > > + addr = sg_dma_address(sg); > > > > + } else { > > > > + if (vring_map_one_sg(vq, sg, DMA_FROM_DEVICE, &addr)) > > > > + goto unmap_release; > > > > + } > > > > > > > > prev = i; > > > > /* Note that we trust indirect descriptor > > > > @@ -689,21 +697,23 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > > > return 0; > > > > > > > > unmap_release: > > > > - err_idx = i; > > > > + if (!vq->premapped) { > > > > > > Can vq->premapped be true here? The label is named as "unmap_relase" > > > which implies "map" beforehand which seems not the case for > > > premapping. > > > > I see. > > > > Rethink about this, there is a better way. > > I will fix in next version. > > > > > > Thanks. > > > > > > > > > > Thanks > > > > > > > > > > + err_idx = i; > > > > > > > > - if (indirect) > > > > - i = 0; > > > > - else > > > > - i = head; > > > > - > > > > - for (n = 0; n < total_sg; n++) { > > > > - if (i == err_idx) > > > > - break; > > > > - if (indirect) { > > > > - vring_unmap_one_split_indirect(vq, &desc[i]); > > > > - i = virtio16_to_cpu(_vq->vdev, desc[i].next); > > > > - } else > > > > - i = vring_unmap_one_split(vq, i); > > > > + if (indirect) > > > > + i = 0; > > > > + else > > > > + i = head; > > > > + > > > > + for (n = 0; n < total_sg; n++) { > > > > + if (i == err_idx) > > > > + break; > > > > + if (indirect) { > > > > + vring_unmap_one_split_indirect(vq, &desc[i]); > > > > + i = virtio16_to_cpu(_vq->vdev, desc[i].next); > > > > + } else > > > > + i = vring_unmap_one_split(vq, i); > > > > + } > > > > } > > > > > > > > if (indirect) > > > > -- > > > > 2.32.0.3.g01195cf9f > > > > > > > > > >