diff mbox series

[net-next,v3,03/13] virtio_ring: packed: record extras for indirect buffers

Message ID 20241107085504.63131-4-xuanzhuo@linux.alibaba.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series virtio-net: support AF_XDP zero copy (tx) | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 3 this patch: 3
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch warning WARNING: line length of 87 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 22 this patch: 22
netdev/source_inline success Was 0 now: 0

Commit Message

Xuan Zhuo Nov. 7, 2024, 8:54 a.m. UTC 
The subsequent commit needs to know whether every indirect buffer is
premapped or not. So we need to introduce an extra struct for every
indirect buffer to record this info.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 60 +++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 24 deletions(-)

Comments

Xuan Zhuo Nov. 11, 2024, 2:59 a.m. UTC | #1 
On Thu,  7 Nov 2024 16:54:54 +0800, Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
> The subsequent commit needs to know whether every indirect buffer is
> premapped or not. So we need to introduce an extra struct for every
> indirect buffer to record this info.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>


Hi, Jason

This also needs a review.

Thanks.


> ---
>  drivers/virtio/virtio_ring.c | 60 +++++++++++++++++++++---------------
>  1 file changed, 36 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 405d5a348795..cfe70c40f630 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -78,7 +78,11 @@ struct vring_desc_state_split {
>
>  struct vring_desc_state_packed {
>  	void *data;			/* Data for callback. */
> -	struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */
> +
> +	/* Indirect desc table and extra table, if any. These two will be
> +	 * allocated together. So we won't stress more to the memory allocator.
> +	 */
> +	struct vring_packed_desc *indir_desc;
>  	u16 num;			/* Descriptor list length. */
>  	u16 last;			/* The last desc state in a list. */
>  };
> @@ -1238,27 +1242,12 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
>  	}
>  }
>
> -static void vring_unmap_desc_packed(const struct vring_virtqueue *vq,
> -				    const struct vring_packed_desc *desc)
> -{
> -	u16 flags;
> -
> -	if (!vring_need_unmap_buffer(vq))
> -		return;
> -
> -	flags = le16_to_cpu(desc->flags);
> -
> -	dma_unmap_page(vring_dma_dev(vq),
> -		       le64_to_cpu(desc->addr),
> -		       le32_to_cpu(desc->len),
> -		       (flags & VRING_DESC_F_WRITE) ?
> -		       DMA_FROM_DEVICE : DMA_TO_DEVICE);
> -}
> -
>  static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
>  						       gfp_t gfp)
>  {
> +	struct vring_desc_extra *extra;
>  	struct vring_packed_desc *desc;
> +	int i, size;
>
>  	/*
>  	 * We require lowmem mappings for the descriptors because
> @@ -1267,7 +1256,16 @@ static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
>  	 */
>  	gfp &= ~__GFP_HIGHMEM;
>
> -	desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp);
> +	size = (sizeof(*desc) + sizeof(*extra)) * total_sg;
> +
> +	desc = kmalloc(size, gfp);
> +	if (!desc)
> +		return NULL;
> +
> +	extra = (struct vring_desc_extra *)&desc[total_sg];
> +
> +	for (i = 0; i < total_sg; i++)
> +		extra[i].next = i + 1;
>
>  	return desc;
>  }
> @@ -1280,6 +1278,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
>  					 void *data,
>  					 gfp_t gfp)
>  {
> +	struct vring_desc_extra *extra;
>  	struct vring_packed_desc *desc;
>  	struct scatterlist *sg;
>  	unsigned int i, n, err_idx;
> @@ -1291,6 +1290,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
>  	if (!desc)
>  		return -ENOMEM;
>
> +	extra = (struct vring_desc_extra *)&desc[total_sg];
> +
>  	if (unlikely(vq->vq.num_free < 1)) {
>  		pr_debug("Can't add buf len 1 - avail = 0\n");
>  		kfree(desc);
> @@ -1312,6 +1313,13 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
>  						0 : VRING_DESC_F_WRITE);
>  			desc[i].addr = cpu_to_le64(addr);
>  			desc[i].len = cpu_to_le32(sg->length);
> +
> +			if (unlikely(vq->use_dma_api)) {
> +				extra[i].addr = addr;
> +				extra[i].len = sg->length;
> +				extra[i].flags = n < out_sgs ?  0 : VRING_DESC_F_WRITE;
> +			}
> +
>  			i++;
>  		}
>  	}
> @@ -1381,7 +1389,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
>  	err_idx = i;
>
>  	for (i = 0; i < err_idx; i++)
> -		vring_unmap_desc_packed(vq, &desc[i]);
> +		vring_unmap_extra_packed(vq, &extra[i]);
>
>  free_desc:
>  	kfree(desc);
> @@ -1617,7 +1625,8 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
>  	}
>
>  	if (vq->indirect) {
> -		u32 len;
> +		struct vring_desc_extra *extra;
> +		u32 len, num;
>
>  		/* Free the indirect table, if any, now that it's unmapped. */
>  		desc = state->indir_desc;
> @@ -1626,9 +1635,12 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
>
>  		if (vring_need_unmap_buffer(vq)) {
>  			len = vq->packed.desc_extra[id].len;
> -			for (i = 0; i < len / sizeof(struct vring_packed_desc);
> -					i++)
> -				vring_unmap_desc_packed(vq, &desc[i]);
> +			num = len / sizeof(struct vring_packed_desc);
> +
> +			extra = (struct vring_desc_extra *)&desc[num];
> +
> +			for (i = 0; i < num; i++)
> +				vring_unmap_extra_packed(vq, &extra[i]);
>  		}
>  		kfree(desc);
>  		state->indir_desc = NULL;
> --
> 2.32.0.3.g01195cf9f
>
Jason Wang Nov. 11, 2024, 4:11 a.m. UTC | #2 
On Mon, Nov 11, 2024 at 11:53 AM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
>
> On Thu,  7 Nov 2024 16:54:54 +0800, Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
> > The subsequent commit needs to know whether every indirect buffer is
> > premapped or not. So we need to introduce an extra struct for every
> > indirect buffer to record this info.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
>
>
> Hi, Jason
>
> This also needs a review.

Sorry, I miss this.

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks
diff mbox series

Patch

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 405d5a348795..cfe70c40f630 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -78,7 +78,11 @@  struct vring_desc_state_split {
 
 struct vring_desc_state_packed {
 	void *data;			/* Data for callback. */
-	struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */
+
+	/* Indirect desc table and extra table, if any. These two will be
+	 * allocated together. So we won't stress more to the memory allocator.
+	 */
+	struct vring_packed_desc *indir_desc;
 	u16 num;			/* Descriptor list length. */
 	u16 last;			/* The last desc state in a list. */
 };
@@ -1238,27 +1242,12 @@  static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
 	}
 }
 
-static void vring_unmap_desc_packed(const struct vring_virtqueue *vq,
-				    const struct vring_packed_desc *desc)
-{
-	u16 flags;
-
-	if (!vring_need_unmap_buffer(vq))
-		return;
-
-	flags = le16_to_cpu(desc->flags);
-
-	dma_unmap_page(vring_dma_dev(vq),
-		       le64_to_cpu(desc->addr),
-		       le32_to_cpu(desc->len),
-		       (flags & VRING_DESC_F_WRITE) ?
-		       DMA_FROM_DEVICE : DMA_TO_DEVICE);
-}
-
 static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
 						       gfp_t gfp)
 {
+	struct vring_desc_extra *extra;
 	struct vring_packed_desc *desc;
+	int i, size;
 
 	/*
 	 * We require lowmem mappings for the descriptors because
@@ -1267,7 +1256,16 @@  static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
 	 */
 	gfp &= ~__GFP_HIGHMEM;
 
-	desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp);
+	size = (sizeof(*desc) + sizeof(*extra)) * total_sg;
+
+	desc = kmalloc(size, gfp);
+	if (!desc)
+		return NULL;
+
+	extra = (struct vring_desc_extra *)&desc[total_sg];
+
+	for (i = 0; i < total_sg; i++)
+		extra[i].next = i + 1;
 
 	return desc;
 }
@@ -1280,6 +1278,7 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 					 void *data,
 					 gfp_t gfp)
 {
+	struct vring_desc_extra *extra;
 	struct vring_packed_desc *desc;
 	struct scatterlist *sg;
 	unsigned int i, n, err_idx;
@@ -1291,6 +1290,8 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	if (!desc)
 		return -ENOMEM;
 
+	extra = (struct vring_desc_extra *)&desc[total_sg];
+
 	if (unlikely(vq->vq.num_free < 1)) {
 		pr_debug("Can't add buf len 1 - avail = 0\n");
 		kfree(desc);
@@ -1312,6 +1313,13 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 						0 : VRING_DESC_F_WRITE);
 			desc[i].addr = cpu_to_le64(addr);
 			desc[i].len = cpu_to_le32(sg->length);
+
+			if (unlikely(vq->use_dma_api)) {
+				extra[i].addr = addr;
+				extra[i].len = sg->length;
+				extra[i].flags = n < out_sgs ?  0 : VRING_DESC_F_WRITE;
+			}
+
 			i++;
 		}
 	}
@@ -1381,7 +1389,7 @@  static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	err_idx = i;
 
 	for (i = 0; i < err_idx; i++)
-		vring_unmap_desc_packed(vq, &desc[i]);
+		vring_unmap_extra_packed(vq, &extra[i]);
 
 free_desc:
 	kfree(desc);
@@ -1617,7 +1625,8 @@  static void detach_buf_packed(struct vring_virtqueue *vq,
 	}
 
 	if (vq->indirect) {
-		u32 len;
+		struct vring_desc_extra *extra;
+		u32 len, num;
 
 		/* Free the indirect table, if any, now that it's unmapped. */
 		desc = state->indir_desc;
@@ -1626,9 +1635,12 @@  static void detach_buf_packed(struct vring_virtqueue *vq,
 
 		if (vring_need_unmap_buffer(vq)) {
 			len = vq->packed.desc_extra[id].len;
-			for (i = 0; i < len / sizeof(struct vring_packed_desc);
-					i++)
-				vring_unmap_desc_packed(vq, &desc[i]);
+			num = len / sizeof(struct vring_packed_desc);
+
+			extra = (struct vring_desc_extra *)&desc[num];
+
+			for (i = 0; i < num; i++)
+				vring_unmap_extra_packed(vq, &extra[i]);
 		}
 		kfree(desc);
 		state->indir_desc = NULL;