DMA-related logic is separated from the virtqueue_add_vring_packed() to
prepare for subsequent support for premapped.

DMA address will be saved as sg->dma_address, then
virtqueue_add_vring_packed() will use it directly.

If it is a premapped scene, the transmitted sgs should have saved DMA
address in dma_address, and in virtio core, we need to pass
virtqueue_map_sgs().

Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 59 ++++++++----------------------------
 1 file changed, 12 insertions(+), 47 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 6796cbee0207..81a9c0692fec 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1350,7 +1350,7 @@ static int virtqueue_add_indirect_packed(struct 
vring_virtqueue *vq,
                                         struct vring_packed_desc *desc)
 {
        struct scatterlist *sg;
-       unsigned int i, n, err_idx;
+       unsigned int i, n;
        u16 head, id;
        dma_addr_t addr;
 
@@ -1362,14 +1362,9 @@ static int virtqueue_add_indirect_packed(struct 
vring_virtqueue *vq,
 
        for (n = 0; n < out_sgs + in_sgs; n++) {
                for (sg = sgs[n]; sg; sg = sg_next(sg)) {
-                       addr = vring_map_one_sg(vq, sg, n < out_sgs ?
-                                       DMA_TO_DEVICE : DMA_FROM_DEVICE);
-                       if (vring_mapping_error(vq, addr))
-                               goto unmap_release;
-
                        desc[i].flags = cpu_to_le16(n < out_sgs ?
                                                0 : VRING_DESC_F_WRITE);
-                       desc[i].addr = cpu_to_le64(addr);
+                       desc[i].addr = cpu_to_le64(sg->dma_address);
                        desc[i].len = cpu_to_le32(sg->length);
                        i++;
                }
@@ -1380,7 +1375,7 @@ static int virtqueue_add_indirect_packed(struct 
vring_virtqueue *vq,
                        total_sg * sizeof(struct vring_packed_desc),
                        DMA_TO_DEVICE);
        if (vring_mapping_error(vq, addr))
-               goto unmap_release;
+               return -ENOMEM;
 
        vq->packed.vring.desc[head].addr = cpu_to_le64(addr);
        vq->packed.vring.desc[head].len = cpu_to_le32(total_sg *
@@ -1429,16 +1424,6 @@ static int virtqueue_add_indirect_packed(struct 
vring_virtqueue *vq,
        pr_debug("Added buffer head %i to %p\n", head, vq);
 
        return 0;
-
-unmap_release:
-       err_idx = i;
-
-       for (i = 0; i < err_idx; i++)
-               vring_unmap_desc_packed(vq, &desc[i]);
-
-       kfree(desc);
-
-       return -ENOMEM;
 }
 
 static inline struct vring_packed_desc *virtqueue_get_desc_packed(struct 
vring_virtqueue *vq,
@@ -1498,15 +1483,14 @@ static inline int virtqueue_add_vring_packed(struct 
vring_virtqueue *vq,
 {
        struct vring_packed_desc *desc;
        struct scatterlist *sg;
-       unsigned int i, n, c, descs_used, err_idx;
+       unsigned int i, n, c, descs_used;
        __le16 head_flags, flags;
-       u16 head, id, prev, curr, avail_used_flags;
+       u16 head, id, prev, curr;
 
        desc = vq->packed.vring.desc;
        head = vq->packed.next_avail_idx;
        i = head;
        descs_used = total_sg;
-       avail_used_flags = vq->packed.avail_used_flags;
 
        id = vq->free_head;
        BUG_ON(id == vq->packed.vring.num);
@@ -1515,11 +1499,6 @@ static inline int virtqueue_add_vring_packed(struct 
vring_virtqueue *vq,
        c = 0;
        for (n = 0; 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, n < out_sgs ?
-                                       DMA_TO_DEVICE : DMA_FROM_DEVICE);
-                       if (vring_mapping_error(vq, addr))
-                               goto unmap_release;
-
                        flags = cpu_to_le16(vq->packed.avail_used_flags |
                                    (++c == total_sg ? 0 : VRING_DESC_F_NEXT) |
                                    (n < out_sgs ? 0 : VRING_DESC_F_WRITE));
@@ -1528,12 +1507,12 @@ static inline int virtqueue_add_vring_packed(struct 
vring_virtqueue *vq,
                        else
                                desc[i].flags = flags;
 
-                       desc[i].addr = cpu_to_le64(addr);
+                       desc[i].addr = cpu_to_le64(sg->dma_address);
                        desc[i].len = cpu_to_le32(sg->length);
                        desc[i].id = cpu_to_le16(id);
 
                        if (unlikely(vq->use_dma_api)) {
-                               vq->packed.desc_extra[curr].addr = addr;
+                               vq->packed.desc_extra[curr].addr = 
sg->dma_address;
                                vq->packed.desc_extra[curr].len = sg->length;
                                vq->packed.desc_extra[curr].flags =
                                        le16_to_cpu(flags);
@@ -1576,25 +1555,6 @@ static inline int virtqueue_add_vring_packed(struct 
vring_virtqueue *vq,
        pr_debug("Added buffer head %i to %p\n", head, vq);
 
        return 0;
-
-unmap_release:
-       err_idx = i;
-       i = head;
-       curr = vq->free_head;
-
-       vq->packed.avail_used_flags = avail_used_flags;
-
-       for (n = 0; n < total_sg; n++) {
-               if (i == err_idx)
-                       break;
-               vring_unmap_extra_packed(vq, &vq->packed.desc_extra[curr]);
-               curr = vq->packed.desc_extra[curr].next;
-               i++;
-               if (i >= vq->packed.vring.num)
-                       i = 0;
-       }
-
-       return -EIO;
 }
 
 static inline int virtqueue_add_packed(struct virtqueue *_vq,
@@ -1621,6 +1581,10 @@ static inline int virtqueue_add_packed(struct virtqueue 
*_vq,
                goto end;
        }
 
+       err = virtqueue_map_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
+       if (err)
+               goto err;
+
        id = vq->free_head;
 
        if (desc) {
@@ -1637,6 +1601,7 @@ static inline int virtqueue_add_packed(struct virtqueue 
*_vq,
        goto end;
 
 err:
+       virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
        kfree(desc);
 
 end:
-- 
2.32.0.3.g01195cf9f

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