dma-buf: remove kmap_atomic interface

Neither used nor correctly implemented anywhere. Just completely remove
the interface.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/226645/

drivers/dma-buf/dma-buf.c

@@ -405,7 +405,6 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 			  || !exp_info->ops->map_dma_buf
 			  || !exp_info->ops->unmap_dma_buf
 			  || !exp_info->ops->release
-			  || !exp_info->ops->map_atomic
 			  || !exp_info->ops->map
 			  || !exp_info->ops->mmap)) {
 		return ERR_PTR(-EINVAL);
@@ -687,26 +686,14 @@ EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
  *      void \*dma_buf_kmap(struct dma_buf \*, unsigned long);
  *      void dma_buf_kunmap(struct dma_buf \*, unsigned long, void \*);
  *
- *   There are also atomic variants of these interfaces. Like for kmap they
- *   facilitate non-blocking fast-paths. Neither the importer nor the exporter
- *   (in the callback) is allowed to block when using these.
- *
- *   Interfaces::
- *      void \*dma_buf_kmap_atomic(struct dma_buf \*, unsigned long);
- *      void dma_buf_kunmap_atomic(struct dma_buf \*, unsigned long, void \*);
- *
- *   For importers all the restrictions of using kmap apply, like the limited
- *   supply of kmap_atomic slots. Hence an importer shall only hold onto at
- *   max 2 atomic dma_buf kmaps at the same time (in any given process context).
+ *   Implementing the functions is optional for exporters and for importers all
+ *   the restrictions of using kmap apply.
  *
  *   dma_buf kmap calls outside of the range specified in begin_cpu_access are
  *   undefined. If the range is not PAGE_SIZE aligned, kmap needs to succeed on
  *   the partial chunks at the beginning and end but may return stale or bogus
  *   data outside of the range (in these partial chunks).
  *
- *   Note that these calls need to always succeed. The exporter needs to
- *   complete any preparations that might fail in begin_cpu_access.
- *
  *   For some cases the overhead of kmap can be too high, a vmap interface
  *   is introduced. This interface should be used very carefully, as vmalloc
  *   space is a limited resources on many architectures.
@@ -859,43 +846,6 @@ int dma_buf_end_cpu_access(struct dma_buf *dmabuf,
 }
 EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access);
 
-/**
- * dma_buf_kmap_atomic - Map a page of the buffer object into kernel address
- * space. The same restrictions as for kmap_atomic and friends apply.
- * @dmabuf:	[in]	buffer to map page from.
- * @page_num:	[in]	page in PAGE_SIZE units to map.
- *
- * This call must always succeed, any necessary preparations that might fail
- * need to be done in begin_cpu_access.
- */
-void *dma_buf_kmap_atomic(struct dma_buf *dmabuf, unsigned long page_num)
-{
-	WARN_ON(!dmabuf);
-
-	if (!dmabuf->ops->map_atomic)
-		return NULL;
-	return dmabuf->ops->map_atomic(dmabuf, page_num);
-}
-EXPORT_SYMBOL_GPL(dma_buf_kmap_atomic);
-
-/**
- * dma_buf_kunmap_atomic - Unmap a page obtained by dma_buf_kmap_atomic.
- * @dmabuf:	[in]	buffer to unmap page from.
- * @page_num:	[in]	page in PAGE_SIZE units to unmap.
- * @vaddr:	[in]	kernel space pointer obtained from dma_buf_kmap_atomic.
- *
- * This call must always succeed.
- */
-void dma_buf_kunmap_atomic(struct dma_buf *dmabuf, unsigned long page_num,
-			   void *vaddr)
-{
-	WARN_ON(!dmabuf);
-
-	if (dmabuf->ops->unmap_atomic)
-		dmabuf->ops->unmap_atomic(dmabuf, page_num, vaddr);
-}
-EXPORT_SYMBOL_GPL(dma_buf_kunmap_atomic);
-
 /**
  * dma_buf_kmap - Map a page of the buffer object into kernel address space. The
  * same restrictions as for kmap and friends apply.

drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c

@@ -238,9 +238,7 @@ static const struct dma_buf_ops amdgpu_dmabuf_ops = {
 	.release = drm_gem_dmabuf_release,
 	.begin_cpu_access = amdgpu_gem_begin_cpu_access,
 	.map = drm_gem_dmabuf_kmap,
-	.map_atomic = drm_gem_dmabuf_kmap_atomic,
 	.unmap = drm_gem_dmabuf_kunmap,
-	.unmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 	.mmap = drm_gem_dmabuf_mmap,
 	.vmap = drm_gem_dmabuf_vmap,
 	.vunmap = drm_gem_dmabuf_vunmap,

drivers/gpu/drm/armada/armada_gem.c

@@ -490,8 +490,6 @@ static const struct dma_buf_ops armada_gem_prime_dmabuf_ops = {
 	.map_dma_buf	= armada_gem_prime_map_dma_buf,
 	.unmap_dma_buf	= armada_gem_prime_unmap_dma_buf,
 	.release	= drm_gem_dmabuf_release,
-	.map_atomic	= armada_gem_dmabuf_no_kmap,
-	.unmap_atomic	= armada_gem_dmabuf_no_kunmap,
 	.map		= armada_gem_dmabuf_no_kmap,
 	.unmap		= armada_gem_dmabuf_no_kunmap,
 	.mmap		= armada_gem_dmabuf_mmap,

drivers/gpu/drm/drm_prime.c

@@ -433,35 +433,6 @@ void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 }
 EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
 
-/**
- * drm_gem_dmabuf_kmap_atomic - map_atomic implementation for GEM
- * @dma_buf: buffer to be mapped
- * @page_num: page number within the buffer
- *
- * Not implemented. This can be used as the &dma_buf_ops.map_atomic callback.
- */
-void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
-				 unsigned long page_num)
-{
-	return NULL;
-}
-EXPORT_SYMBOL(drm_gem_dmabuf_kmap_atomic);
-
-/**
- * drm_gem_dmabuf_kunmap_atomic - unmap_atomic implementation for GEM
- * @dma_buf: buffer to be unmapped
- * @page_num: page number within the buffer
- * @addr: virtual address of the buffer
- *
- * Not implemented. This can be used as the &dma_buf_ops.unmap_atomic callback.
- */
-void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
-				  unsigned long page_num, void *addr)
-{
-
-}
-EXPORT_SYMBOL(drm_gem_dmabuf_kunmap_atomic);
-
 /**
  * drm_gem_dmabuf_kmap - map implementation for GEM
  * @dma_buf: buffer to be mapped
@@ -519,9 +490,7 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 	.unmap_dma_buf = drm_gem_unmap_dma_buf,
 	.release = drm_gem_dmabuf_release,
 	.map = drm_gem_dmabuf_kmap,
-	.map_atomic = drm_gem_dmabuf_kmap_atomic,
 	.unmap = drm_gem_dmabuf_kunmap,
-	.unmap_atomic = drm_gem_dmabuf_kunmap_atomic,
 	.mmap = drm_gem_dmabuf_mmap,
 	.vmap = drm_gem_dmabuf_vmap,
 	.vunmap = drm_gem_dmabuf_vunmap,

drivers/gpu/drm/i915/i915_gem_dmabuf.c

@@ -111,15 +111,6 @@ static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 	i915_gem_object_unpin_map(obj);
 }
 
-static void *i915_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf, unsigned long page_num)
-{
-	return NULL;
-}
-
-static void i915_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf, unsigned long page_num, void *addr)
-{
-
-}
 static void *i915_gem_dmabuf_kmap(struct dma_buf *dma_buf, unsigned long page_num)
 {
 	struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
@@ -225,9 +216,7 @@ static const struct dma_buf_ops i915_dmabuf_ops =  {
 	.unmap_dma_buf = i915_gem_unmap_dma_buf,
 	.release = drm_gem_dmabuf_release,
 	.map = i915_gem_dmabuf_kmap,
-	.map_atomic = i915_gem_dmabuf_kmap_atomic,
 	.unmap = i915_gem_dmabuf_kunmap,
-	.unmap_atomic = i915_gem_dmabuf_kunmap_atomic,
 	.mmap = i915_gem_dmabuf_mmap,
 	.vmap = i915_gem_dmabuf_vmap,
 	.vunmap = i915_gem_dmabuf_vunmap,

drivers/gpu/drm/i915/selftests/mock_dmabuf.c

@@ -130,9 +130,7 @@ static const struct dma_buf_ops mock_dmabuf_ops =  {
 	.unmap_dma_buf = mock_unmap_dma_buf,
 	.release = mock_dmabuf_release,
 	.map = mock_dmabuf_kmap,
-	.map_atomic = mock_dmabuf_kmap_atomic,
 	.unmap = mock_dmabuf_kunmap,
-	.unmap_atomic = mock_dmabuf_kunmap_atomic,
 	.mmap = mock_dmabuf_mmap,
 	.vmap = mock_dmabuf_vmap,
 	.vunmap = mock_dmabuf_vunmap,

drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c

@@ -148,8 +148,6 @@ static const struct dma_buf_ops omap_dmabuf_ops = {
 	.release = drm_gem_dmabuf_release,
 	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
 	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
-	.map_atomic = omap_gem_dmabuf_kmap_atomic,
-	.unmap_atomic = omap_gem_dmabuf_kunmap_atomic,
 	.map = omap_gem_dmabuf_kmap,
 	.unmap = omap_gem_dmabuf_kunmap,
 	.mmap = omap_gem_dmabuf_mmap,

drivers/gpu/drm/tegra/gem.c

@@ -596,18 +596,6 @@ static int tegra_gem_prime_end_cpu_access(struct dma_buf *buf,
 	return 0;
 }
 
-static void *tegra_gem_prime_kmap_atomic(struct dma_buf *buf,
-					 unsigned long page)
-{
-	return NULL;
-}
-
-static void tegra_gem_prime_kunmap_atomic(struct dma_buf *buf,
-					  unsigned long page,
-					  void *addr)
-{
-}
-
 static void *tegra_gem_prime_kmap(struct dma_buf *buf, unsigned long page)
 {
 	return NULL;
@@ -648,8 +636,6 @@ static const struct dma_buf_ops tegra_gem_prime_dmabuf_ops = {
 	.release = tegra_gem_prime_release,
 	.begin_cpu_access = tegra_gem_prime_begin_cpu_access,
 	.end_cpu_access = tegra_gem_prime_end_cpu_access,
-	.map_atomic = tegra_gem_prime_kmap_atomic,
-	.unmap_atomic = tegra_gem_prime_kunmap_atomic,
 	.map = tegra_gem_prime_kmap,
 	.unmap = tegra_gem_prime_kunmap,
 	.mmap = tegra_gem_prime_mmap,

drivers/gpu/drm/udl/udl_dmabuf.c

@@ -157,27 +157,12 @@ static void *udl_dmabuf_kmap(struct dma_buf *dma_buf, unsigned long page_num)
 	return NULL;
 }
 
-static void *udl_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
-				    unsigned long page_num)
-{
-	/* TODO */
-
-	return NULL;
-}
-
 static void udl_dmabuf_kunmap(struct dma_buf *dma_buf,
 			      unsigned long page_num, void *addr)
 {
 	/* TODO */
 }
 
-static void udl_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
-				     unsigned long page_num,
-				     void *addr)
-{
-	/* TODO */
-}
-
 static int udl_dmabuf_mmap(struct dma_buf *dma_buf,
 			   struct vm_area_struct *vma)
 {
@@ -192,9 +177,7 @@ static const struct dma_buf_ops udl_dmabuf_ops = {
 	.map_dma_buf		= udl_map_dma_buf,
 	.unmap_dma_buf		= udl_unmap_dma_buf,
 	.map			= udl_dmabuf_kmap,
-	.map_atomic		= udl_dmabuf_kmap_atomic,
 	.unmap			= udl_dmabuf_kunmap,
-	.unmap_atomic		= udl_dmabuf_kunmap_atomic,
 	.mmap			= udl_dmabuf_mmap,
 	.release		= drm_gem_dmabuf_release,
 };

drivers/gpu/drm/vmwgfx/vmwgfx_prime.c

@@ -71,17 +71,6 @@ static void vmw_prime_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 {
 }
 
-static void *vmw_prime_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
-		unsigned long page_num)
-{
-	return NULL;
-}
-
-static void vmw_prime_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
-		unsigned long page_num, void *addr)
-{
-
-}
 static void *vmw_prime_dmabuf_kmap(struct dma_buf *dma_buf,
 		unsigned long page_num)
 {
@@ -108,9 +97,7 @@ const struct dma_buf_ops vmw_prime_dmabuf_ops =  {
 	.unmap_dma_buf = vmw_prime_unmap_dma_buf,
 	.release = NULL,
 	.map = vmw_prime_dmabuf_kmap,
-	.map_atomic = vmw_prime_dmabuf_kmap_atomic,
 	.unmap = vmw_prime_dmabuf_kunmap,
-	.unmap_atomic = vmw_prime_dmabuf_kunmap_atomic,
 	.mmap = vmw_prime_dmabuf_mmap,
 	.vmap = vmw_prime_dmabuf_vmap,
 	.vunmap = vmw_prime_dmabuf_vunmap,

drivers/media/common/videobuf2/videobuf2-dma-contig.c

@@ -358,7 +358,6 @@ static const struct dma_buf_ops vb2_dc_dmabuf_ops = {
 	.map_dma_buf = vb2_dc_dmabuf_ops_map,
 	.unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
 	.map = vb2_dc_dmabuf_ops_kmap,
-	.map_atomic = vb2_dc_dmabuf_ops_kmap,
 	.vmap = vb2_dc_dmabuf_ops_vmap,
 	.mmap = vb2_dc_dmabuf_ops_mmap,
 	.release = vb2_dc_dmabuf_ops_release,

drivers/media/common/videobuf2/videobuf2-dma-sg.c

@@ -507,7 +507,6 @@ static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
 	.map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
 	.unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
 	.map = vb2_dma_sg_dmabuf_ops_kmap,
-	.map_atomic = vb2_dma_sg_dmabuf_ops_kmap,
 	.vmap = vb2_dma_sg_dmabuf_ops_vmap,
 	.mmap = vb2_dma_sg_dmabuf_ops_mmap,
 	.release = vb2_dma_sg_dmabuf_ops_release,

drivers/media/common/videobuf2/videobuf2-vmalloc.c

@@ -346,7 +346,6 @@ static const struct dma_buf_ops vb2_vmalloc_dmabuf_ops = {
 	.map_dma_buf = vb2_vmalloc_dmabuf_ops_map,
 	.unmap_dma_buf = vb2_vmalloc_dmabuf_ops_unmap,
 	.map = vb2_vmalloc_dmabuf_ops_kmap,
-	.map_atomic = vb2_vmalloc_dmabuf_ops_kmap,
 	.vmap = vb2_vmalloc_dmabuf_ops_vmap,
 	.mmap = vb2_vmalloc_dmabuf_ops_mmap,
 	.release = vb2_vmalloc_dmabuf_ops_release,

drivers/staging/android/ion/ion.c

@@ -369,8 +369,6 @@ static const struct dma_buf_ops dma_buf_ops = {
 	.detach = ion_dma_buf_detatch,
 	.begin_cpu_access = ion_dma_buf_begin_cpu_access,
 	.end_cpu_access = ion_dma_buf_end_cpu_access,
-	.map_atomic = ion_dma_buf_kmap,
-	.unmap_atomic = ion_dma_buf_kunmap,
 	.map = ion_dma_buf_kmap,
 	.unmap = ion_dma_buf_kunmap,
 };

drivers/tee/tee_shm.c

@@ -80,11 +80,6 @@ static void tee_shm_op_release(struct dma_buf *dmabuf)
 	tee_shm_release(shm);
 }
 
-static void *tee_shm_op_map_atomic(struct dma_buf *dmabuf, unsigned long pgnum)
-{
-	return NULL;
-}
-
 static void *tee_shm_op_map(struct dma_buf *dmabuf, unsigned long pgnum)
 {
 	return NULL;
@@ -107,7 +102,6 @@ static const struct dma_buf_ops tee_shm_dma_buf_ops = {
 	.map_dma_buf = tee_shm_op_map_dma_buf,
 	.unmap_dma_buf = tee_shm_op_unmap_dma_buf,
 	.release = tee_shm_op_release,
-	.map_atomic = tee_shm_op_map_atomic,
 	.map = tee_shm_op_map,
 	.mmap = tee_shm_op_mmap,
 };

include/drm/drm_prime.h

@@ -93,10 +93,6 @@ void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 			   enum dma_data_direction dir);
 void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf);
 void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr);
-void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
-				 unsigned long page_num);
-void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
-				  unsigned long page_num, void *addr);
 void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf, unsigned long page_num);
 void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf, unsigned long page_num,
 			   void *addr);

include/linux/dma-buf.h

@@ -205,8 +205,6 @@ struct dma_buf_ops {
 	 * to be restarted.
 	 */
 	int (*end_cpu_access)(struct dma_buf *, enum dma_data_direction);
-	void *(*map_atomic)(struct dma_buf *, unsigned long);
-	void (*unmap_atomic)(struct dma_buf *, unsigned long, void *);
 	void *(*map)(struct dma_buf *, unsigned long);
 	void (*unmap)(struct dma_buf *, unsigned long, void *);
 
@@ -394,8 +392,6 @@ int dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
 			     enum dma_data_direction dir);
 int dma_buf_end_cpu_access(struct dma_buf *dma_buf,
 			   enum dma_data_direction dir);
-void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long);
-void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *);
 void *dma_buf_kmap(struct dma_buf *, unsigned long);
 void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);