[PATCH vhost v1 16/19] virtio_ring: introduce virtqueue_dma_map_sg_attrs
From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Date: 2024-02-02 09:40:21
Also in:
bpf, kvm, linux-remoteproc, linux-s390, linux-um, platform-driver-x86, virtualization
Subsystem:
the rest, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
Introduce a helper to do dma map for scatterlist. That can be used by other drivers. Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> --- drivers/virtio/virtio_ring.c | 32 ++++++++++++++++++++++++++++++++ include/linux/virtio.h | 3 +++ 2 files changed, 35 insertions(+)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 79868967a676..9b1d0859cb1c 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c@@ -3187,6 +3187,38 @@ int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr) } EXPORT_SYMBOL_GPL(virtqueue_dma_mapping_error); +/** + * virtqueue_dma_map_sg_attrs - map scatterlist addr DMA for _vq + * @_vq: the struct virtqueue we're talking about. + * @sg: the scatterlist to do dma + * @dir: DMA direction + * @attrs: DMA Attrs + * + * The caller calls this to do dma mapping in advance. The sg can be + * passed to this _vq when it is in pre-mapped mode. + * + * Returns zero or a negative error. + * 0: success + * -ENOMEM: dma map error + */ +int virtqueue_dma_map_sg_attrs(struct virtqueue *_vq, struct scatterlist *sg, + enum dma_data_direction dir, unsigned long attrs) +{ + dma_addr_t addr; + int err; + + addr = virtqueue_dma_map_page_attrs(_vq, sg_page(sg), sg->offset, + sg->length, dir, attrs); + err = virtqueue_dma_mapping_error(_vq, addr); + if (err) + return err; + + sg->dma_address = addr; + + return 0; +} +EXPORT_SYMBOL_GPL(virtqueue_dma_map_sg_attrs); + /** * virtqueue_dma_need_sync - check a dma address needs sync * @_vq: the struct virtqueue we're talking about.
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 8a8d282982ad..36d16eda341e 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h@@ -225,6 +225,9 @@ void virtqueue_dma_unmap_page_attrs(struct virtqueue *_vq, dma_addr_t addr, unsigned long attrs); int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr); +int virtqueue_dma_map_sg_attrs(struct virtqueue *_vq, struct scatterlist *sg, + enum dma_data_direction dir, unsigned long attrs); + bool virtqueue_dma_need_sync(struct virtqueue *_vq, dma_addr_t addr); void virtqueue_dma_sync_single_range_for_cpu(struct virtqueue *_vq, dma_addr_t addr, unsigned long offset, size_t size,
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2.32.0.3.g01195cf9f