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 | 122 +++++++++++++++++++++++++++--------
1 file changed, 94 insertions(+), 28 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 41144b5246a8..2aafb7da793d 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))
+ goto err_map;
+
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,
@@ -679,23 +759,9 @@ 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);
+err_map:
if (indirect)
kfree(desc);
--
2.32.0.3.g01195cf9f
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