Allow ttm_buffer_object without resource

Allow ttm_buffer_object without resource

[Christian König]

Hi guys,

this patch set cleans up the handling of TTM buffer objects quite a bit
by allowing to create them without allocating a ttm_resource as well.

That's not only cleaner in general, but also a necessary prerequisite for
quite a number of related work.

Please review and comment,
Christian.

[PATCH 01/11] drm/radeon: switch over to ttm_bo_init_reserved

[Christian König]

Use the new interface instead.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/radeon/radeon_object.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index b827b87aefe2..7afafbbc4ea0 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -133,9 +133,12 @@ int radeon_bo_create(struct radeon_device *rdev,
 		     struct dma_resv *resv,
 		     struct radeon_bo **bo_ptr)
 {
-	struct radeon_bo *bo;
-	enum ttm_bo_type type;
 	unsigned long page_align = roundup(byte_align, PAGE_SIZE) >> PAGE_SHIFT;
+
+	/* Kernel allocation are uninterruptible */
+	struct ttm_operation_ctx ctx = { !kernel, false };
+	enum ttm_bo_type type;
+	struct radeon_bo *bo;
 	int r;
 
 	size = ALIGN(size, PAGE_SIZE);
@@ -200,11 +203,13 @@ int radeon_bo_create(struct radeon_device *rdev,
 #endif
 
 	radeon_ttm_placement_from_domain(bo, domain);
-	/* Kernel allocation are uninterruptible */
 	down_read(&rdev->pm.mclk_lock);
-	r = ttm_bo_init(&rdev->mman.bdev, &bo->tbo, size, type,
-			&bo->placement, page_align, !kernel, sg, resv,
-			&radeon_ttm_bo_destroy);
+	r = ttm_bo_init_reserved(&rdev->mman.bdev, &bo->tbo, size, type,
+				 &bo->placement, page_align, &ctx, sg, resv,
+				 &radeon_ttm_bo_destroy);
+        if (!r)
+		ttm_bo_unreserve(&bo->tbo);
+
 	up_read(&rdev->pm.mclk_lock);
 	if (unlikely(r != 0)) {
 		return r;
-- 
2.25.1

[PATCH 02/11] drm/nouveau: switch over to ttm_bo_init_reserved

[Christian König]

Use the new interface instead.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/nouveau/nouveau_bo.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index fa73fe57f97b..ceac591a7c01 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -302,19 +302,23 @@ nouveau_bo_init(struct nouveau_bo *nvbo, u64 size, int align, u32 domain,
 		struct sg_table *sg, struct dma_resv *robj)
 {
 	int type = sg ? ttm_bo_type_sg : ttm_bo_type_device;
+	struct ttm_operation_ctx ctx = { false, false };
 	int ret;
 
 	nouveau_bo_placement_set(nvbo, domain, 0);
 	INIT_LIST_HEAD(&nvbo->io_reserve_lru);
 
-	ret = ttm_bo_init(nvbo->bo.bdev, &nvbo->bo, size, type,
-			  &nvbo->placement, align >> PAGE_SHIFT, false, sg,
-			  robj, nouveau_bo_del_ttm);
+	ret = ttm_bo_init_reserved(nvbo->bo.bdev, &nvbo->bo, size, type,
+				   &nvbo->placement, align >> PAGE_SHIFT, &ctx,
+				   sg, robj, nouveau_bo_del_ttm);
 	if (ret) {
 		/* ttm will call nouveau_bo_del_ttm if it fails.. */
 		return ret;
 	}
 
+	if (!robj)
+		ttm_bo_unreserve(&nvbo->bo);
+
 	return 0;
 }
 
-- 
2.25.1

[PATCH 03/11] drm/vram-helper: switch over to ttm_bo_init_reserved

[Christian König]

Use the new interface instead.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/drm_gem_vram_helper.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index 3f00192215d1..0bd46a138ded 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -186,6 +186,7 @@ struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
 						size_t size,
 						unsigned long pg_align)
 {
+	struct ttm_operation_ctx ctx = { false, false };
 	struct drm_gem_vram_object *gbo;
 	struct drm_gem_object *gem;
 	struct drm_vram_mm *vmm = dev->vram_mm;
@@ -225,12 +226,13 @@ struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
 	 * A failing ttm_bo_init will call ttm_buffer_object_destroy
 	 * to release gbo->bo.base and kfree gbo.
 	 */
-	ret = ttm_bo_init(bdev, &gbo->bo, size, ttm_bo_type_device,
-			  &gbo->placement, pg_align, false, NULL, NULL,
-			  ttm_buffer_object_destroy);
-	if (ret)
+	ret = ttm_bo_init_reserved(bdev, &gbo->bo, size, ttm_bo_type_device,
+				   &gbo->placement, pg_align, &ctx, NULL, NULL,
+				   ttm_buffer_object_destroy);
+        if (ret)
 		return ERR_PTR(ret);
 
+	ttm_bo_unreserve(&gbo->bo);
 	return gbo;
 }
 EXPORT_SYMBOL(drm_gem_vram_create);
-- 
2.25.1

[PATCH 04/11] drm/ttm: move default BO destructor into VMWGFX

[Christian König]

It's the only driver using this.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c       |  9 +--------
 drivers/gpu/drm/vmwgfx/vmwgfx_bo.c | 11 ++++++++++-
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index e5fd0f2c0299..7598d59423bf 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -44,12 +44,6 @@
 
 #include "ttm_module.h"
 
-/* default destructor */
-static void ttm_bo_default_destroy(struct ttm_buffer_object *bo)
-{
-	kfree(bo);
-}
-
 static void ttm_bo_mem_space_debug(struct ttm_buffer_object *bo,
 					struct ttm_placement *placement)
 {
@@ -938,8 +932,7 @@ int ttm_bo_init_reserved(struct ttm_device *bdev,
 	bool locked;
 	int ret;
 
-	bo->destroy = destroy ? destroy : ttm_bo_default_destroy;
-
+	bo->destroy = destroy;
 	kref_init(&bo->kref);
 	INIT_LIST_HEAD(&bo->ddestroy);
 	bo->bdev = bdev;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
index 31aecc46624b..60dcc6a75248 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
@@ -378,6 +378,12 @@ void vmw_bo_bo_free(struct ttm_buffer_object *bo)
 	kfree(vmw_bo);
 }
 
+/* default destructor */
+static void vmw_bo_default_destroy(struct ttm_buffer_object *bo)
+{
+	kfree(bo);
+}
+
 /**
  * vmw_bo_create_kernel - Create a pinned BO for internal kernel use.
  *
@@ -410,7 +416,7 @@ int vmw_bo_create_kernel(struct vmw_private *dev_priv, unsigned long size,
 
 	ret = ttm_bo_init_reserved(&dev_priv->bdev, bo, size,
 				   ttm_bo_type_kernel, placement, 0,
-				   &ctx, NULL, NULL, NULL);
+				   &ctx, NULL, NULL, vmw_bo_default_destroy);
 	if (unlikely(ret))
 		goto error_free;
 
@@ -439,6 +445,9 @@ int vmw_bo_create(struct vmw_private *vmw,
 		return -ENOMEM;
 	}
 
+	if (!bo_free)
+		bo_free = vmw_bo_default_destroy;
+
 	ret = vmw_bo_init(vmw, *p_bo, size,
 			  placement, interruptible, pin,
 			  bo_free);
-- 
2.25.1

[PATCH 05/11] drm/ttm: drop ttm_bo_init

[Christian König]

Not used any more.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 26 ---------------------
 include/drm/ttm/ttm_bo_api.h | 44 ------------------------------------
 2 files changed, 70 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 7598d59423bf..37f68e710247 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -988,32 +988,6 @@ int ttm_bo_init_reserved(struct ttm_device *bdev,
 }
 EXPORT_SYMBOL(ttm_bo_init_reserved);
 
-int ttm_bo_init(struct ttm_device *bdev,
-		struct ttm_buffer_object *bo,
-		size_t size,
-		enum ttm_bo_type type,
-		struct ttm_placement *placement,
-		uint32_t page_alignment,
-		bool interruptible,
-		struct sg_table *sg,
-		struct dma_resv *resv,
-		void (*destroy) (struct ttm_buffer_object *))
-{
-	struct ttm_operation_ctx ctx = { interruptible, false };
-	int ret;
-
-	ret = ttm_bo_init_reserved(bdev, bo, size, type, placement,
-				   page_alignment, &ctx, sg, resv, destroy);
-	if (ret)
-		return ret;
-
-	if (!resv)
-		ttm_bo_unreserve(bo);
-
-	return 0;
-}
-EXPORT_SYMBOL(ttm_bo_init);
-
 /*
  * buffer object vm functions.
  */
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index c61e1e5ceb83..51fbbd035c11 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -363,50 +363,6 @@ int ttm_bo_init_reserved(struct ttm_device *bdev,
 			 struct sg_table *sg, struct dma_resv *resv,
 			 void (*destroy) (struct ttm_buffer_object *));
 
-/**
- * ttm_bo_init
- *
- * @bdev: Pointer to a ttm_device struct.
- * @bo: Pointer to a ttm_buffer_object to be initialized.
- * @size: Requested size of buffer object.
- * @type: Requested type of buffer object.
- * @placement: Initial placement for buffer object.
- * @page_alignment: Data alignment in pages.
- * @interruptible: If needing to sleep to wait for GPU resources,
- * sleep interruptible.
- * pinned in physical memory. If this behaviour is not desired, this member
- * holds a pointer to a persistent shmem object. Typically, this would
- * point to the shmem object backing a GEM object if TTM is used to back a
- * GEM user interface.
- * @sg: Scatter-gather table.
- * @resv: Pointer to a dma_resv, or NULL to let ttm allocate one.
- * @destroy: Destroy function. Use NULL for kfree().
- *
- * This function initializes a pre-allocated struct ttm_buffer_object.
- * As this object may be part of a larger structure, this function,
- * together with the @destroy function,
- * enables driver-specific objects derived from a ttm_buffer_object.
- *
- * On successful return, the caller owns an object kref to @bo. The kref and
- * list_kref are usually set to 1, but note that in some situations, other
- * tasks may already be holding references to @bo as well.
- *
- * If a failure occurs, the function will call the @destroy function, or
- * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
- * illegal and will likely cause memory corruption.
- *
- * Returns
- * -ENOMEM: Out of memory.
- * -EINVAL: Invalid placement flags.
- * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
- */
-int ttm_bo_init(struct ttm_device *bdev, struct ttm_buffer_object *bo,
-		size_t size, enum ttm_bo_type type,
-		struct ttm_placement *placement,
-		uint32_t page_alignment, bool interrubtible,
-		struct sg_table *sg, struct dma_resv *resv,
-		void (*destroy) (struct ttm_buffer_object *));
-
 /**
  * ttm_kmap_obj_virtual
  *
-- 
2.25.1

[PATCH 06/11] drm/ttm: rename and cleanup ttm_bo_init_reserved

[Christian König]

Rename ttm_bo_init_reserved to ttm_bo_init_validate since that better
matches what the function is actually doing.

Remove the unused size parameter, move the function's kerneldoc to the
implementation and cleanup the whole error handling.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c |  2 +-
 drivers/gpu/drm/drm_gem_vram_helper.c      |  2 +-
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c    |  5 +-
 drivers/gpu/drm/nouveau/nouveau_bo.c       |  2 +-
 drivers/gpu/drm/qxl/qxl_object.c           |  2 +-
 drivers/gpu/drm/radeon/radeon_object.c     |  2 +-
 drivers/gpu/drm/ttm/ttm_bo.c               | 92 ++++++++++++++--------
 drivers/gpu/drm/vmwgfx/vmwgfx_bo.c         | 12 ++-
 include/drm/ttm/ttm_bo_api.h               | 44 +----------
 9 files changed, 75 insertions(+), 88 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index ea0cde4904f0..4cb3afbdf6b9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -587,7 +587,7 @@ int amdgpu_bo_create(struct amdgpu_device *adev,
 	if (!bp->destroy)
 		bp->destroy = &amdgpu_bo_destroy;
 
-	r = ttm_bo_init_reserved(&adev->mman.bdev, &bo->tbo, size, bp->type,
+	r = ttm_bo_init_validate(&adev->mman.bdev, &bo->tbo, bp->type,
 				 &bo->placement, page_align, &ctx,  NULL,
 				 bp->resv, bp->destroy);
 	if (unlikely(r != 0))
diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index 0bd46a138ded..3e678d49265c 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -226,7 +226,7 @@ struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
 	 * A failing ttm_bo_init will call ttm_buffer_object_destroy
 	 * to release gbo->bo.base and kfree gbo.
 	 */
-	ret = ttm_bo_init_reserved(bdev, &gbo->bo, size, ttm_bo_type_device,
+	ret = ttm_bo_init_validate(bdev, &gbo->bo, ttm_bo_type_device,
 				   &gbo->placement, pg_align, &ctx, NULL, NULL,
 				   ttm_buffer_object_destroy);
         if (ret)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 6fc192082d8c..10d89bde7dd3 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -1075,9 +1075,8 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
 	 * Similarly, in delayed_destroy, we can't call ttm_bo_put()
 	 * until successful initialization.
 	 */
-	ret = ttm_bo_init_reserved(&i915->bdev, i915_gem_to_ttm(obj), size,
-				   bo_type, &i915_sys_placement,
-				   page_size >> PAGE_SHIFT,
+	ret = ttm_bo_init_validate(&i915->bdev, i915_gem_to_ttm(obj), bo_type,
+				   &i915_sys_placement, page_size >> PAGE_SHIFT,
 				   &ctx, NULL, NULL, i915_ttm_bo_destroy);
 	if (ret)
 		return i915_ttm_err_to_gem(ret);
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index ceac591a7c01..43c862bbbbfb 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -308,7 +308,7 @@ nouveau_bo_init(struct nouveau_bo *nvbo, u64 size, int align, u32 domain,
 	nouveau_bo_placement_set(nvbo, domain, 0);
 	INIT_LIST_HEAD(&nvbo->io_reserve_lru);
 
-	ret = ttm_bo_init_reserved(nvbo->bo.bdev, &nvbo->bo, size, type,
+	ret = ttm_bo_init_validate(nvbo->bo.bdev, &nvbo->bo, type,
 				   &nvbo->placement, align >> PAGE_SHIFT, &ctx,
 				   sg, robj, nouveau_bo_del_ttm);
 	if (ret) {
diff --git a/drivers/gpu/drm/qxl/qxl_object.c b/drivers/gpu/drm/qxl/qxl_object.c
index fbb36e3e8564..e4dbce4afdd0 100644
--- a/drivers/gpu/drm/qxl/qxl_object.c
+++ b/drivers/gpu/drm/qxl/qxl_object.c
@@ -141,7 +141,7 @@ int qxl_bo_create(struct qxl_device *qdev, unsigned long size,
 	qxl_ttm_placement_from_domain(bo, domain);
 
 	bo->tbo.priority = priority;
-	r = ttm_bo_init_reserved(&qdev->mman.bdev, &bo->tbo, size, type,
+	r = ttm_bo_init_validate(&qdev->mman.bdev, &bo->tbo, type,
 				 &bo->placement, 0, &ctx, NULL, NULL,
 				 &qxl_ttm_bo_destroy);
 	if (unlikely(r != 0)) {
diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index 7afafbbc4ea0..9d255170b771 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -204,7 +204,7 @@ int radeon_bo_create(struct radeon_device *rdev,
 
 	radeon_ttm_placement_from_domain(bo, domain);
 	down_read(&rdev->pm.mclk_lock);
-	r = ttm_bo_init_reserved(&rdev->mman.bdev, &bo->tbo, size, type,
+	r = ttm_bo_init_validate(&rdev->mman.bdev, &bo->tbo, type,
 				 &bo->placement, page_align, &ctx, sg, resv,
 				 &radeon_ttm_bo_destroy);
         if (!r)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 37f68e710247..b7e259245f82 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -917,37 +917,62 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
 }
 EXPORT_SYMBOL(ttm_bo_validate);
 
-int ttm_bo_init_reserved(struct ttm_device *bdev,
-			 struct ttm_buffer_object *bo,
-			 size_t size,
-			 enum ttm_bo_type type,
-			 struct ttm_placement *placement,
-			 uint32_t page_alignment,
-			 struct ttm_operation_ctx *ctx,
-			 struct sg_table *sg,
-			 struct dma_resv *resv,
+/**
+ * ttm_bo_init_validate
+ *
+ * @bdev: Pointer to a ttm_device struct.
+ * @bo: Pointer to a ttm_buffer_object to be initialized.
+ * @type: Requested type of buffer object.
+ * @placement: Initial placement for buffer object.
+ * @alignment: Data alignment in pages.
+ * @ctx: TTM operation context for memory allocation.
+ * @sg: Scatter-gather table.
+ * @resv: Pointer to a dma_resv, or NULL to let ttm allocate one.
+ * @destroy: Destroy function. Use NULL for kfree().
+ *
+ * This function initializes a pre-allocated struct ttm_buffer_object.
+ * As this object may be part of a larger structure, this function,
+ * together with the @destroy function, enables driver-specific objects
+ * derived from a ttm_buffer_object.
+ *
+ * On successful return, the caller owns an object kref to @bo. The kref and
+ * list_kref are usually set to 1, but note that in some situations, other
+ * tasks may already be holding references to @bo as well.
+ * Furthermore, if resv == NULL, the buffer's reservation lock will be held,
+ * and it is the caller's responsibility to call ttm_bo_unreserve.
+ *
+ * If a failure occurs, the function will call the @destroy function. Thus,
+ * after a failure, dereferencing @bo is illegal and will likely cause memory
+ * corruption.
+ *
+ * Returns
+ * -ENOMEM: Out of memory.
+ * -EINVAL: Invalid placement flags.
+ * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
+ */
+int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
+			 enum ttm_bo_type type, struct ttm_placement *placement,
+			 uint32_t alignment, struct ttm_operation_ctx *ctx,
+			 struct sg_table *sg, struct dma_resv *resv,
 			 void (*destroy) (struct ttm_buffer_object *))
 {
 	static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
-	bool locked;
 	int ret;
 
-	bo->destroy = destroy;
 	kref_init(&bo->kref);
 	INIT_LIST_HEAD(&bo->ddestroy);
 	bo->bdev = bdev;
 	bo->type = type;
-	bo->page_alignment = page_alignment;
+	bo->page_alignment = alignment;
+	bo->destroy = destroy;
 	bo->moving = NULL;
 	bo->pin_count = 0;
 	bo->sg = sg;
 	bo->bulk_move = NULL;
-	if (resv) {
+	if (resv)
 		bo->base.resv = resv;
-		dma_resv_assert_held(bo->base.resv);
-	} else {
+	else
 		bo->base.resv = &bo->base._resv;
-	}
 	atomic_inc(&ttm_glob.bo_count);
 
 	ret = ttm_resource_alloc(bo, &sys_mem, &bo->resource);
@@ -960,33 +985,36 @@ int ttm_bo_init_reserved(struct ttm_device *bdev,
 	 * For ttm_bo_type_device buffers, allocate
 	 * address space from the device.
 	 */
-	if (bo->type == ttm_bo_type_device ||
-	    bo->type == ttm_bo_type_sg)
+	if (bo->type == ttm_bo_type_device || bo->type == ttm_bo_type_sg) {
 		ret = drm_vma_offset_add(bdev->vma_manager, &bo->base.vma_node,
-					 bo->resource->num_pages);
+					 PFN_UP(bo->base.size));
+		if (ret)
+			goto err_put;
+	}
 
 	/* passed reservation objects should already be locked,
 	 * since otherwise lockdep will be angered in radeon.
 	 */
-	if (!resv) {
-		locked = dma_resv_trylock(bo->base.resv);
-		WARN_ON(!locked);
-	}
+	if (!resv)
+		WARN_ON(!dma_resv_trylock(bo->base.resv));
+	else
+		dma_resv_assert_held(resv);
 
-	if (likely(!ret))
-		ret = ttm_bo_validate(bo, placement, ctx);
+	ret = ttm_bo_validate(bo, placement, ctx);
+	if (unlikely(ret))
+		goto err_unlock;
 
-	if (unlikely(ret)) {
-		if (!resv)
-			ttm_bo_unreserve(bo);
+	return 0;
 
-		ttm_bo_put(bo);
-		return ret;
-	}
+err_unlock:
+	if (!resv)
+		dma_resv_unlock(bo->base.resv);
 
+err_put:
+	ttm_bo_put(bo);
 	return ret;
 }
-EXPORT_SYMBOL(ttm_bo_init_reserved);
+EXPORT_SYMBOL(ttm_bo_init_validate);
 
 /*
  * buffer object vm functions.
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
index 60dcc6a75248..052a68408b85 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
@@ -414,9 +414,9 @@ int vmw_bo_create_kernel(struct vmw_private *dev_priv, unsigned long size,
 
 	drm_gem_private_object_init(vdev, &bo->base, size);
 
-	ret = ttm_bo_init_reserved(&dev_priv->bdev, bo, size,
-				   ttm_bo_type_kernel, placement, 0,
-				   &ctx, NULL, NULL, vmw_bo_default_destroy);
+	ret = ttm_bo_init_validate(&dev_priv->bdev, bo, ttm_bo_type_kernel,
+				   placement, 0, &ctx, NULL, NULL,
+				   vmw_bo_default_destroy);
 	if (unlikely(ret))
 		goto error_free;
 
@@ -498,10 +498,8 @@ int vmw_bo_init(struct vmw_private *dev_priv,
 	size = ALIGN(size, PAGE_SIZE);
 	drm_gem_private_object_init(vdev, &vmw_bo->base.base, size);
 
-	ret = ttm_bo_init_reserved(bdev, &vmw_bo->base, size,
-				   ttm_bo_type_device,
-				   placement,
-				   0, &ctx, NULL, NULL, bo_free);
+	ret = ttm_bo_init_validate(bdev, &vmw_bo->base, ttm_bo_type_device,
+				   placement, 0, &ctx, NULL, NULL, bo_free);
 	if (unlikely(ret)) {
 		return ret;
 	}
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 51fbbd035c11..4b3bb6cfca39 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -319,47 +319,9 @@ void ttm_bo_unlock_delayed_workqueue(struct ttm_device *bdev, int resched);
 bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
 			      const struct ttm_place *place);
 
-/**
- * ttm_bo_init_reserved
- *
- * @bdev: Pointer to a ttm_device struct.
- * @bo: Pointer to a ttm_buffer_object to be initialized.
- * @size: Requested size of buffer object.
- * @type: Requested type of buffer object.
- * @placement: Initial placement for buffer object.
- * @page_alignment: Data alignment in pages.
- * @ctx: TTM operation context for memory allocation.
- * @sg: Scatter-gather table.
- * @resv: Pointer to a dma_resv, or NULL to let ttm allocate one.
- * @destroy: Destroy function. Use NULL for kfree().
- *
- * This function initializes a pre-allocated struct ttm_buffer_object.
- * As this object may be part of a larger structure, this function,
- * together with the @destroy function,
- * enables driver-specific objects derived from a ttm_buffer_object.
- *
- * On successful return, the caller owns an object kref to @bo. The kref and
- * list_kref are usually set to 1, but note that in some situations, other
- * tasks may already be holding references to @bo as well.
- * Furthermore, if resv == NULL, the buffer's reservation lock will be held,
- * and it is the caller's responsibility to call ttm_bo_unreserve.
- *
- * If a failure occurs, the function will call the @destroy function, or
- * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
- * illegal and will likely cause memory corruption.
- *
- * Returns
- * -ENOMEM: Out of memory.
- * -EINVAL: Invalid placement flags.
- * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
- */
-
-int ttm_bo_init_reserved(struct ttm_device *bdev,
-			 struct ttm_buffer_object *bo,
-			 size_t size, enum ttm_bo_type type,
-			 struct ttm_placement *placement,
-			 uint32_t page_alignment,
-			 struct ttm_operation_ctx *ctx,
+int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
+			 enum ttm_bo_type type, struct ttm_placement *placement,
+			 uint32_t alignment, struct ttm_operation_ctx *ctx,
 			 struct sg_table *sg, struct dma_resv *resv,
 			 void (*destroy) (struct ttm_buffer_object *));
 
-- 
2.25.1

[PATCH 07/11] drm/amdgpu: audit bo->resource usage

[Christian König]

Make sure we can at least move and release BOs without backing store.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 4cb3afbdf6b9..49e8ba118322 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -1299,7 +1299,7 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
 	if (bo->base.resv == &bo->base._resv)
 		amdgpu_amdkfd_remove_fence_on_pt_pd_bos(abo);
 
-	if (bo->resource->mem_type != TTM_PL_VRAM ||
+	if (!bo->resource || bo->resource->mem_type != TTM_PL_VRAM ||
 	    !(abo->flags & AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE))
 		return;
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 57ac118fc266..22954c84df39 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -476,7 +476,8 @@ static int amdgpu_bo_move(struct ttm_buffer_object *bo, bool evict,
 
 	adev = amdgpu_ttm_adev(bo->bdev);
 
-	if (old_mem->mem_type == TTM_PL_SYSTEM && bo->ttm == NULL) {
+	if (!old_mem || (old_mem->mem_type == TTM_PL_SYSTEM &&
+			 bo->ttm == NULL)) {
 		ttm_bo_move_null(bo, new_mem);
 		goto out;
 	}
-- 
2.25.1

[PATCH 08/11] drm/nouveau: audit bo->resource usage

[Christian König]

Make sure we can at least move and release BOs without backing store.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/nouveau/nouveau_bo.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 43c862bbbbfb..5b937d68a291 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -1003,7 +1003,8 @@ nouveau_bo_move(struct ttm_buffer_object *bo, bool evict,
 	}
 
 	/* Fake bo copy. */
-	if (old_reg->mem_type == TTM_PL_SYSTEM && !bo->ttm) {
+	if (!old_reg || (old_reg->mem_type == TTM_PL_SYSTEM &&
+			 !bo->ttm)) {
 		ttm_bo_move_null(bo, new_reg);
 		goto out;
 	}
-- 
2.25.1

[PATCH 09/11] drm/ttm: audit bo->resource usage

[Christian König]

Allow BOs to exist without backing store.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index b7e259245f82..bd001fdde9fb 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -117,12 +117,13 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 				  struct ttm_operation_ctx *ctx,
 				  struct ttm_place *hop)
 {
-	struct ttm_resource_manager *old_man, *new_man;
 	struct ttm_device *bdev = bo->bdev;
+	bool old_use_tt, new_use_tt;
 	int ret;
 
-	old_man = ttm_manager_type(bdev, bo->resource->mem_type);
-	new_man = ttm_manager_type(bdev, mem->mem_type);
+	old_use_tt = bo->resource &&
+		ttm_manager_type(bdev, bo->resource->mem_type)->use_tt;
+	new_use_tt = ttm_manager_type(bdev, mem->mem_type)->use_tt;
 
 	ttm_bo_unmap_virtual(bo);
 
@@ -130,11 +131,11 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 	 * Create and bind a ttm if required.
 	 */
 
-	if (new_man->use_tt) {
+	if (new_use_tt) {
 		/* Zero init the new TTM structure if the old location should
 		 * have used one as well.
 		 */
-		ret = ttm_tt_create(bo, old_man->use_tt);
+		ret = ttm_tt_create(bo, old_use_tt);
 		if (ret)
 			goto out_err;
 
@@ -156,8 +157,7 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 	return 0;
 
 out_err:
-	new_man = ttm_manager_type(bdev, bo->resource->mem_type);
-	if (!new_man->use_tt)
+	if (!old_use_tt)
 		ttm_bo_tt_destroy(bo);
 
 	return ret;
@@ -900,7 +900,7 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
 	/*
 	 * Check whether we need to move buffer.
 	 */
-	if (!ttm_resource_compat(bo->resource, placement)) {
+	if (!bo->resource || !ttm_resource_compat(bo->resource, placement)) {
 		ret = ttm_bo_move_buffer(bo, placement, ctx);
 		if (ret)
 			return ret;
-- 
2.25.1

[PATCH 10/11] drm/ttm: stop allocating dummy resources during BO creation

[Christian König]

That should not be necessary any more when drivers should at least be
able to handle the move without a resource.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index bd001fdde9fb..9d40641dcf39 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -956,7 +956,6 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
 			 struct sg_table *sg, struct dma_resv *resv,
 			 void (*destroy) (struct ttm_buffer_object *))
 {
-	static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
 	int ret;
 
 	kref_init(&bo->kref);
@@ -975,12 +974,6 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
 		bo->base.resv = &bo->base._resv;
 	atomic_inc(&ttm_glob.bo_count);
 
-	ret = ttm_resource_alloc(bo, &sys_mem, &bo->resource);
-	if (unlikely(ret)) {
-		ttm_bo_put(bo);
-		return ret;
-	}
-
 	/*
 	 * For ttm_bo_type_device buffers, allocate
 	 * address space from the device.
-- 
2.25.1

[PATCH 11/11] drm/ttm: stop allocating a dummy resource for pipelined gutting

[Christian König]

That should not be necessary any more when drivers should at least be
able to handle a move without a resource.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo_util.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 0163e92b57af..979abe095f42 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -585,16 +585,10 @@ EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);
  */
 int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
 {
-	static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
 	struct ttm_buffer_object *ghost;
-	struct ttm_resource *sys_res;
 	struct ttm_tt *ttm;
 	int ret;
 
-	ret = ttm_resource_alloc(bo, &sys_mem, &sys_res);
-	if (ret)
-		return ret;
-
 	/* If already idle, no need for ghost object dance. */
 	ret = ttm_bo_wait(bo, false, true);
 	if (ret != -EBUSY) {
@@ -602,14 +596,13 @@ int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
 			/* See comment below about clearing. */
 			ret = ttm_tt_create(bo, true);
 			if (ret)
-				goto error_free_sys_mem;
+				return ret;
 		} else {
 			ttm_tt_unpopulate(bo->bdev, bo->ttm);
 			if (bo->type == ttm_bo_type_device)
 				ttm_tt_mark_for_clear(bo->ttm);
 		}
 		ttm_resource_free(bo, &bo->resource);
-		ttm_bo_assign_mem(bo, sys_res);
 		return 0;
 	}
 
@@ -626,7 +619,7 @@ int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
 	ret = ttm_tt_create(bo, true);
 	swap(bo->ttm, ttm);
 	if (ret)
-		goto error_free_sys_mem;
+		return ret;
 
 	ret = ttm_buffer_object_transfer(bo, &ghost);
 	if (ret)
@@ -640,13 +633,9 @@ int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
 	dma_resv_unlock(&ghost->base._resv);
 	ttm_bo_put(ghost);
 	bo->ttm = ttm;
-	ttm_bo_assign_mem(bo, sys_res);
 	return 0;
 
 error_destroy_tt:
 	ttm_tt_destroy(bo->bdev, ttm);
-
-error_free_sys_mem:
-	ttm_resource_free(bo, &sys_res);
 	return ret;
 }
-- 
2.25.1

Re: Allow ttm_buffer_object without resource

[Daniel Vetter]

On Tue, Mar 29, 2022 at 01:02:32PM +0200, Christian König wrote:
> Hi guys,
> 
> this patch set cleans up the handling of TTM buffer objects quite a bit
> by allowing to create them without allocating a ttm_resource as well.
> 
> That's not only cleaner in general, but also a necessary prerequisite for
> quite a number of related work.

Maybe there's some threads I missed, but I can't really guess what this
could be useful for without even a hint.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: Allow ttm_buffer_object without resource

[Christian König]

Am 29.03.22 um 16:02 schrieb Daniel Vetter:
> On Tue, Mar 29, 2022 at 01:02:32PM +0200, Christian König wrote:
>> Hi guys,
>>
>> this patch set cleans up the handling of TTM buffer objects quite a bit
>> by allowing to create them without allocating a ttm_resource as well.
>>
>> That's not only cleaner in general, but also a necessary prerequisite for
>> quite a number of related work.
> Maybe there's some threads I missed, but I can't really guess what this
> could be useful for without even a hint.

Well about a week ago Bob send me a partial implementation of this and 
said he needs it for i915. What exactly i915 needs here I'm not sure 
about either.

I have this cleanup in the pipeline because amdgpu wants to improve his 
page table handling with this and independent of those driver use case 
patches #10 and #11 drop allocating dummy resources for two use cases in 
TTM.

Christian.

> -Daniel

Re: [PATCH 04/11] drm/ttm: move default BO destructor into VMWGFX

[Zack Rusin]

On Tue, 2022-03-29 at 13:02 +0200, Christian König wrote:
> ⚠ External Email
> 
> It's the only driver using this.
> 
> Signed-off-by: Christian König <christian.koenig@amd.com>

Looks good. A small suggestion underneath.

Reviewed-by: Zack Rusin <zackr@vmware.com>

> ---
>  drivers/gpu/drm/ttm/ttm_bo.c       |  9 +--------
>  drivers/gpu/drm/vmwgfx/vmwgfx_bo.c | 11 ++++++++++-
>  2 files changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c
> b/drivers/gpu/drm/ttm/ttm_bo.c
> index e5fd0f2c0299..7598d59423bf 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -44,12 +44,6 @@
> 
>  #include "ttm_module.h"
> 
> -/* default destructor */
> -static void ttm_bo_default_destroy(struct ttm_buffer_object *bo)
> -{
> -       kfree(bo);
> -}
> -
>  static void ttm_bo_mem_space_debug(struct ttm_buffer_object *bo,
>                                         struct ttm_placement
> *placement)
>  {
> @@ -938,8 +932,7 @@ int ttm_bo_init_reserved(struct ttm_device *bdev,
>         bool locked;
>         int ret;
> 
> -       bo->destroy = destroy ? destroy : ttm_bo_default_destroy;
> -
> +       bo->destroy = destroy;
>         kref_init(&bo->kref);
>         INIT_LIST_HEAD(&bo->ddestroy);
>         bo->bdev = bdev;
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
> b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
> index 31aecc46624b..60dcc6a75248 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
> @@ -378,6 +378,12 @@ void vmw_bo_bo_free(struct ttm_buffer_object
> *bo)
>         kfree(vmw_bo);
>  }
> 
> +/* default destructor */
> +static void vmw_bo_default_destroy(struct ttm_buffer_object *bo)
> +{
> +       kfree(bo);
> +}
> +
>  /**
>   * vmw_bo_create_kernel - Create a pinned BO for internal kernel
> use.
>   *
> @@ -410,7 +416,7 @@ int vmw_bo_create_kernel(struct vmw_private
> *dev_priv, unsigned long size,
> 
>         ret = ttm_bo_init_reserved(&dev_priv->bdev, bo, size,
>                                    ttm_bo_type_kernel, placement, 0,
> -                                  &ctx, NULL, NULL, NULL);
> +                                  &ctx, NULL, NULL,
> vmw_bo_default_destroy);
>         if (unlikely(ret))
>                 goto error_free;
> 
> @@ -439,6 +445,9 @@ int vmw_bo_create(struct vmw_private *vmw,
>                 return -ENOMEM;
>         }
> 
> +       if (!bo_free)
> +               bo_free = vmw_bo_default_destroy;
> +

If you could change this to just  BUG_ON(!bo_free) that'd be great.
bo_free == NULL should never happen here.

z

[PATCH 10/11] drm/ttm: stop allocating dummy resources during BO creation

[Christian König]

That should not be necessary any more when drivers should at least be
able to handle the move without a resource.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index a55564c8b57c..31aa4b040d1e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -954,7 +954,6 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
 			 struct sg_table *sg, struct dma_resv *resv,
 			 void (*destroy) (struct ttm_buffer_object *))
 {
-	static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
 	int ret;
 
 	kref_init(&bo->kref);
@@ -972,12 +971,6 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
 		bo->base.resv = &bo->base._resv;
 	atomic_inc(&ttm_glob.bo_count);
 
-	ret = ttm_resource_alloc(bo, &sys_mem, &bo->resource);
-	if (unlikely(ret)) {
-		ttm_bo_put(bo);
-		return ret;
-	}
-
 	/*
 	 * For ttm_bo_type_device buffers, allocate
 	 * address space from the device.
-- 
2.25.1

[PATCH 10/11] drm/ttm: stop allocating dummy resources during BO creation

[Christian König]

That should not be necessary any more when drivers should at least be
able to handle the move without a resource.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index a55564c8b57c..31aa4b040d1e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -954,7 +954,6 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
 			 struct sg_table *sg, struct dma_resv *resv,
 			 void (*destroy) (struct ttm_buffer_object *))
 {
-	static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM };
 	int ret;
 
 	kref_init(&bo->kref);
@@ -972,12 +971,6 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
 		bo->base.resv = &bo->base._resv;
 	atomic_inc(&ttm_glob.bo_count);
 
-	ret = ttm_resource_alloc(bo, &sys_mem, &bo->resource);
-	if (unlikely(ret)) {
-		ttm_bo_put(bo);
-		return ret;
-	}
-
 	/*
 	 * For ttm_bo_type_device buffers, allocate
 	 * address space from the device.
-- 
2.25.1