virtqueue_add_packed() only supports virtual addresses, dma is completed
in virtqueue_add_packed().
In some scenarios (such as the AF_XDP scenario), the memory is allocated
and DMA is completed in advance, so it is necessary for us to support
passing the DMA address to virtqueue_add_packed().
Record this information in desc_state, we can skip unmap based on this
when executing dma unmap.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_ring.c | 71 +++++++++++++++++++++++++-----------
1 file changed, 50 insertions(+), 21 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index ec622403cbd5..25027a35fcf8 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -78,6 +78,7 @@ struct vring_desc_state_packed {
struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */
u16 num; /* Descriptor list length. */
u16 last; /* The last desc state in a list. */
+ bool premapped;
};
struct vring_desc_extra {
@@ -1200,7 +1201,8 @@ static inline u16 packed_last_used(u16 last_used_idx)
}
static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
- struct vring_desc_extra *extra)
+ struct vring_desc_extra *extra,
+ bool premapped)
{
u16 flags;
@@ -1215,6 +1217,9 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
(flags & VRING_DESC_F_WRITE) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE);
} else {
+ if (premapped)
+ return;
+
dma_unmap_page(vring_dma_dev(vq),
extra->addr, extra->len,
(flags & VRING_DESC_F_WRITE) ?
@@ -1262,7 +1267,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
unsigned int out_sgs,
unsigned int in_sgs,
void *data,
- gfp_t gfp)
+ gfp_t gfp,
+ bool premapped)
{
struct vring_packed_desc *desc;
struct scatterlist *sg;
@@ -1288,10 +1294,15 @@ 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;
+ if (premapped) {
+ addr = sg_dma_address(sg);
+
+ } else {
+ 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);
@@ -1350,6 +1361,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
vq->packed.desc_state[id].data = data;
vq->packed.desc_state[id].indir_desc = desc;
vq->packed.desc_state[id].last = id;
+ vq->packed.desc_state[id].premapped = premapped;
vq->num_added += 1;
@@ -1359,10 +1371,11 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
return 0;
unmap_release:
- err_idx = i;
-
- for (i = 0; i < err_idx; i++)
- vring_unmap_desc_packed(vq, &desc[i]);
+ if (!premapped) {
+ err_idx = i;
+ for (i = 0; i < err_idx; i++)
+ vring_unmap_desc_packed(vq, &desc[i]);
+ }
kfree(desc);
@@ -1377,6 +1390,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
unsigned int in_sgs,
void *data,
void *ctx,
+ bool premapped,
gfp_t gfp)
{
struct vring_virtqueue *vq = to_vvq(_vq);
@@ -1403,7 +1417,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
if (virtqueue_use_indirect(vq, total_sg)) {
err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs,
- in_sgs, data, gfp);
+ in_sgs, data, gfp, premapped);
if (err != -ENOMEM) {
END_USE(vq);
return err;
@@ -1435,10 +1449,17 @@ static inline int virtqueue_add_packed(struct 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;
+ dma_addr_t addr;
+
+ if (premapped) {
+ addr = sg_dma_address(sg);
+
+ } else {
+ 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) |
@@ -1485,6 +1506,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
vq->packed.desc_state[id].data = data;
vq->packed.desc_state[id].indir_desc = ctx;
vq->packed.desc_state[id].last = prev;
+ vq->packed.desc_state[id].premapped = premapped;
/*
* A driver MUST NOT make the first descriptor in the list
@@ -1501,22 +1523,26 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
return 0;
unmap_release:
+ vq->packed.avail_used_flags = avail_used_flags;
+
+ if (premapped)
+ goto unmap_free;
+
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]);
+ vring_unmap_extra_packed(vq, &vq->packed.desc_extra[curr], false);
curr = vq->packed.desc_extra[curr].next;
i++;
if (i >= vq->packed.vring.num)
i = 0;
}
+unmap_free:
END_USE(vq);
return -EIO;
}
@@ -1576,8 +1602,10 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
struct vring_desc_state_packed *state = NULL;
struct vring_packed_desc *desc;
unsigned int i, curr;
+ bool premapped;
state = &vq->packed.desc_state[id];
+ premapped = state->premapped;
/* Clear data ptr. */
state->data = NULL;
@@ -1590,7 +1618,8 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
curr = id;
for (i = 0; i < state->num; i++) {
vring_unmap_extra_packed(vq,
- &vq->packed.desc_extra[curr]);
+ &vq->packed.desc_extra[curr],
+ premapped);
curr = vq->packed.desc_extra[curr].next;
}
}
@@ -1603,7 +1632,7 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
if (!desc)
return;
- if (vq->use_dma_api) {
+ if (vq->use_dma_api && !premapped) {
len = vq->packed.desc_extra[id].len;
for (i = 0; i < len / sizeof(struct vring_packed_desc);
i++)
@@ -2122,7 +2151,7 @@ static inline int virtqueue_add(struct virtqueue *_vq,
struct vring_virtqueue *vq = to_vvq(_vq);
return vq->packed_ring ? virtqueue_add_packed(_vq, sgs, total_sg,
- out_sgs, in_sgs, data, ctx, gfp) :
+ out_sgs, in_sgs, data, ctx, premapped, gfp) :
virtqueue_add_split(_vq, sgs, total_sg,
out_sgs, in_sgs, data, ctx, premapped, gfp);
}
--
2.32.0.3.g01195cf9f
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