DMA-related logic is separated from the virtqueue_add_split() to one new function. DMA address will be saved as sg->dma_address if use_dma_api is true, then virtqueue_add_split() will use it directly. Unmap operation will be simpler. The purpose of this is to facilitate subsequent support to receive dma address mapped by drivers. Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> --- drivers/virtio/virtio_ring.c | 121 +++++++++++++++++++++++++++-------- 1 file changed, 93 insertions(+), 28 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 41144b5246a8..fe704ca6c813 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -379,6 +379,14 @@ static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq, direction); } +static dma_addr_t vring_sg_address(struct scatterlist *sg) +{ + if (sg->dma_address) + return sg->dma_address; + + return (dma_addr_t)sg_phys(sg); +} + static dma_addr_t vring_map_single(const struct vring_virtqueue *vq, void *cpu_addr, size_t size, enum dma_data_direction direction) @@ -520,6 +528,80 @@ static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq, return next; } +static void virtqueue_unmap_sgs(struct vring_virtqueue *vq, + struct scatterlist *sgs[], + unsigned int total_sg, + unsigned int out_sgs, + unsigned int in_sgs) +{ + struct scatterlist *sg; + unsigned int n; + + if (!vq->use_dma_api) + return; + + for (n = 0; n < out_sgs; n++) { + for (sg = sgs[n]; sg; sg = sg_next(sg)) { + if (!sg->dma_address) + return; + + dma_unmap_page(vring_dma_dev(vq), sg->dma_address, + sg->length, DMA_TO_DEVICE); + } + } + + for (; n < (out_sgs + in_sgs); n++) { + for (sg = sgs[n]; sg; sg = sg_next(sg)) { + if (!sg->dma_address) + return; + + dma_unmap_page(vring_dma_dev(vq), sg->dma_address, + sg->length, DMA_FROM_DEVICE); + } + } +} + +static int virtqueue_map_sgs(struct vring_virtqueue *vq, + struct scatterlist *sgs[], + unsigned int total_sg, + unsigned int out_sgs, + unsigned int in_sgs) +{ + struct scatterlist *sg; + unsigned int n; + + if (!vq->use_dma_api) + return 0; + + for (n = 0; n < out_sgs; n++) { + for (sg = sgs[n]; sg; sg = sg_next(sg)) { + dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE); + + if (vring_mapping_error(vq, addr)) + goto err; + + sg->dma_address = addr; + } + } + + for (; n < (out_sgs + in_sgs); n++) { + for (sg = sgs[n]; sg; sg = sg_next(sg)) { + dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE); + + if (vring_mapping_error(vq, addr)) + goto err; + + sg->dma_address = addr; + } + } + + return 0; + +err: + virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs); + return -ENOMEM; +} + static inline int virtqueue_add_split(struct virtqueue *_vq, struct scatterlist *sgs[], unsigned int total_sg, @@ -532,9 +614,9 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, struct vring_virtqueue *vq = to_vvq(_vq); struct scatterlist *sg; struct vring_desc *desc; - unsigned int i, n, avail, descs_used, prev, err_idx; - int head; + unsigned int i, n, avail, descs_used, prev; bool indirect; + int head; START_USE(vq); @@ -586,32 +668,30 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, return -ENOSPC; } + if (virtqueue_map_sgs(vq, sgs, total_sg, out_sgs, in_sgs)) + return -ENOMEM; + for (n = 0; n < out_sgs; n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { - dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE); - if (vring_mapping_error(vq, addr)) - goto unmap_release; - prev = i; /* Note that we trust indirect descriptor * table since it use stream DMA mapping. */ - i = virtqueue_add_desc_split(_vq, desc, i, addr, sg->length, + i = virtqueue_add_desc_split(_vq, desc, i, + vring_sg_address(sg), + sg->length, VRING_DESC_F_NEXT, indirect); } } for (; n < (out_sgs + in_sgs); n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { - dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE); - if (vring_mapping_error(vq, addr)) - goto unmap_release; - prev = i; /* Note that we trust indirect descriptor * table since it use stream DMA mapping. */ - i = virtqueue_add_desc_split(_vq, desc, i, addr, + i = virtqueue_add_desc_split(_vq, desc, i, + vring_sg_address(sg), sg->length, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE, @@ -679,22 +759,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, return 0; unmap_release: - 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); - } + virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs); if (indirect) kfree(desc); -- 2.32.0.3.g01195cf9f _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization