[PATCH 4/4] dma-buf: drop caching of sg_tables
Simona Vetter
simona.vetter at ffwll.ch
Mon Feb 17 16:28:05 UTC 2025
On Tue, Feb 11, 2025 at 05:31:09PM +0100, Christian König wrote:
> That was purely for the transition from static to dynamic dma-buf
> handling and can be removed again now.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
Yay!
Might uncover some fun if people have meanwhile started to rely on this
for perf or something. But we'll figure that out when it happens.
Reviewed-by: Simona Vetter <simona.vetter at ffwll.ch>
> ---
> drivers/dma-buf/dma-buf.c | 34 --------------------------
> drivers/dma-buf/udmabuf.c | 1 -
> drivers/gpu/drm/drm_prime.c | 1 -
> drivers/gpu/drm/virtio/virtgpu_prime.c | 1 -
> include/linux/dma-buf.h | 13 ----------
> 5 files changed, 50 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 357b94a3dbaa..35221c4ddbf5 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -636,10 +636,6 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
> || !exp_info->ops->release))
> return ERR_PTR(-EINVAL);
>
> - if (WARN_ON(exp_info->ops->cache_sgt_mapping &&
> - (exp_info->ops->pin || exp_info->ops->unpin)))
> - return ERR_PTR(-EINVAL);
> -
> if (WARN_ON(!exp_info->ops->pin != !exp_info->ops->unpin))
> return ERR_PTR(-EINVAL);
>
> @@ -964,17 +960,7 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
> return;
>
> dma_resv_lock(dmabuf->resv, NULL);
> -
> - if (attach->sgt) {
> - mangle_sg_table(attach->sgt);
> - attach->dmabuf->ops->unmap_dma_buf(attach, attach->sgt,
> - attach->dir);
> -
> - if (dma_buf_pin_on_map(attach))
> - dma_buf_unpin(attach);
> - }
> list_del(&attach->node);
> -
> dma_resv_unlock(dmabuf->resv);
>
> if (dmabuf->ops->detach)
> @@ -1069,18 +1055,6 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
>
> dma_resv_assert_held(attach->dmabuf->resv);
>
> - if (attach->sgt) {
> - /*
> - * Two mappings with different directions for the same
> - * attachment are not allowed.
> - */
> - if (attach->dir != direction &&
> - attach->dir != DMA_BIDIRECTIONAL)
> - return ERR_PTR(-EBUSY);
> -
> - return attach->sgt;
> - }
> -
> if (dma_buf_pin_on_map(attach)) {
> ret = attach->dmabuf->ops->pin(attach);
> if (ret)
> @@ -1105,11 +1079,6 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
> }
> mangle_sg_table(sg_table);
>
> - if (attach->dmabuf->ops->cache_sgt_mapping) {
> - attach->sgt = sg_table;
> - attach->dir = direction;
> - }
> -
> #ifdef CONFIG_DMA_API_DEBUG
> {
> struct scatterlist *sg;
> @@ -1190,9 +1159,6 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
>
> dma_resv_assert_held(attach->dmabuf->resv);
>
> - if (attach->sgt == sg_table)
> - return;
> -
> mangle_sg_table(sg_table);
> attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);
>
> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
> index cc7398cc17d6..2fa2c9135eac 100644
> --- a/drivers/dma-buf/udmabuf.c
> +++ b/drivers/dma-buf/udmabuf.c
> @@ -285,7 +285,6 @@ static int end_cpu_udmabuf(struct dma_buf *buf,
> }
>
> static const struct dma_buf_ops udmabuf_ops = {
> - .cache_sgt_mapping = true,
> .map_dma_buf = map_udmabuf,
> .unmap_dma_buf = unmap_udmabuf,
> .release = release_udmabuf,
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 32a8781cfd67..c284f306d597 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -810,7 +810,6 @@ int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
> EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
>
> static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
> - .cache_sgt_mapping = true,
> .attach = drm_gem_map_attach,
> .detach = drm_gem_map_detach,
> .map_dma_buf = drm_gem_map_dma_buf,
> diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c
> index fe6a0b018571..c6f3be3cb914 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_prime.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
> @@ -75,7 +75,6 @@ static void virtgpu_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
>
> static const struct virtio_dma_buf_ops virtgpu_dmabuf_ops = {
> .ops = {
> - .cache_sgt_mapping = true,
> .attach = virtio_dma_buf_attach,
> .detach = drm_gem_map_detach,
> .map_dma_buf = virtgpu_gem_map_dma_buf,
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index c54ff2dda8cb..544f8f8c3f44 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -34,15 +34,6 @@ struct dma_buf_attachment;
> * @vunmap: [optional] unmaps a vmap from the buffer
> */
> struct dma_buf_ops {
> - /**
> - * @cache_sgt_mapping:
> - *
> - * If true the framework will cache the first mapping made for each
> - * attachment. This avoids creating mappings for attachments multiple
> - * times.
> - */
> - bool cache_sgt_mapping;
> -
> /**
> * @attach:
> *
> @@ -493,8 +484,6 @@ struct dma_buf_attach_ops {
> * @dmabuf: buffer for this attachment.
> * @dev: device attached to the buffer.
> * @node: list of dma_buf_attachment, protected by dma_resv lock of the dmabuf.
> - * @sgt: cached mapping.
> - * @dir: direction of cached mapping.
> * @peer2peer: true if the importer can handle peer resources without pages.
> * @priv: exporter specific attachment data.
> * @importer_ops: importer operations for this attachment, if provided
> @@ -514,8 +503,6 @@ struct dma_buf_attachment {
> struct dma_buf *dmabuf;
> struct device *dev;
> struct list_head node;
> - struct sg_table *sgt;
> - enum dma_data_direction dir;
> bool peer2peer;
> const struct dma_buf_attach_ops *importer_ops;
> void *importer_priv;
> --
> 2.34.1
>
--
Simona Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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