Commit 9f19c084 authored by Xuan Zhuo's avatar Xuan Zhuo Committed by Jakub Kicinski
Browse files

virtio_ring: introduce vring_need_unmap_buffer 



To make the code readable, introduce vring_need_unmap_buffer() to
replace do_unmap.

   use_dma_api premapped -> vring_need_unmap_buffer()
1. false       false        false
2. true        false        true
3. true        true         false

Signed-off-by: default avatarXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241112012928.102478-2-xuanzhuo@linux.alibaba.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1c978616

drivers/virtio/virtio_ring.c

+12 −15
Original line number Diff line number Diff line
@@ -175,11 +175,6 @@ struct vring_virtqueue { 
	/* Do DMA mapping by driver */

	bool premapped;



	/* Do unmap or not for desc. Just when premapped is False and

	 * use_dma_api is true, this is true.

	 */

	bool do_unmap;



	/* Head of free buffer list. */

	unsigned int free_head;

	/* Number we've added since last sync. */
@@ -297,6 +292,11 @@ static bool vring_use_dma_api(const struct virtio_device *vdev) 
	return false;

}



static bool vring_need_unmap_buffer(const struct vring_virtqueue *vring)

{

	return vring->use_dma_api && !vring->premapped;

}



size_t virtio_max_dma_size(const struct virtio_device *vdev)

{

	size_t max_segment_size = SIZE_MAX;
@@ -445,7 +445,7 @@ static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq, 
{

	u16 flags;



	if (!vq->do_unmap)

	if (!vring_need_unmap_buffer(vq))

		return;



	flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
@@ -475,7 +475,7 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, 
				 (flags & VRING_DESC_F_WRITE) ?

				 DMA_FROM_DEVICE : DMA_TO_DEVICE);

	} else {

		if (!vq->do_unmap)

		if (!vring_need_unmap_buffer(vq))

			goto out;



		dma_unmap_page(vring_dma_dev(vq),
@@ -643,7 +643,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, 
	}

	/* Last one doesn't continue. */

	desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);

	if (!indirect && vq->do_unmap)

	if (!indirect && vring_need_unmap_buffer(vq))

		vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &=

			~VRING_DESC_F_NEXT;
@@ -802,7 +802,7 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, 
				VRING_DESC_F_INDIRECT));

		BUG_ON(len == 0 || len % sizeof(struct vring_desc));



		if (vq->do_unmap) {

		if (vring_need_unmap_buffer(vq)) {

			for (j = 0; j < len / sizeof(struct vring_desc); j++)

				vring_unmap_one_split_indirect(vq, &indir_desc[j]);

		}
@@ -1236,7 +1236,7 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq, 
				 (flags & VRING_DESC_F_WRITE) ?

				 DMA_FROM_DEVICE : DMA_TO_DEVICE);

	} else {

		if (!vq->do_unmap)

		if (!vring_need_unmap_buffer(vq))

			return;



		dma_unmap_page(vring_dma_dev(vq),
@@ -1251,7 +1251,7 @@ static void vring_unmap_desc_packed(const struct vring_virtqueue *vq, 
{

	u16 flags;



	if (!vq->do_unmap)

	if (!vring_need_unmap_buffer(vq))

		return;



	flags = le16_to_cpu(desc->flags);
@@ -1632,7 +1632,7 @@ static void detach_buf_packed(struct vring_virtqueue *vq, 
		if (!desc)

			return;



		if (vq->do_unmap) {

		if (vring_need_unmap_buffer(vq)) {

			len = vq->packed.desc_extra[id].len;

			for (i = 0; i < len / sizeof(struct vring_packed_desc);

					i++)
@@ -2091,7 +2091,6 @@ static struct virtqueue *vring_create_virtqueue_packed( 
	vq->dma_dev = dma_dev;

	vq->use_dma_api = vring_use_dma_api(vdev);

	vq->premapped = false;

	vq->do_unmap = vq->use_dma_api;



	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&

		!context;
@@ -2636,7 +2635,6 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index, 
	vq->dma_dev = dma_dev;

	vq->use_dma_api = vring_use_dma_api(vdev);

	vq->premapped = false;

	vq->do_unmap = vq->use_dma_api;



	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&

		!context;
@@ -2799,7 +2797,6 @@ int virtqueue_set_dma_premapped(struct virtqueue *_vq) 
	}



	vq->premapped = true;

	vq->do_unmap = false;



	END_USE(vq);