[PATCH 4/4] dma-buf: drop caching of sg_tables

[Christian König]

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>
---
 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