drm/ttm: rename and cleanup ttm_bo_init

Rename ttm_bo_init 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>
Link: https://patchwork.freedesktop.org/patch/msgid/20220707102453.3633-2-christian.koenig@amd.com
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>

1 files changed, 103 insertions, 44 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 296af2b89951..dbd331939e6d 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -915,36 +915,61 @@ 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_reserved
+ *
+ * @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_reserved(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->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);
@@ -957,50 +982,84 @@ 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);
 
-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 *))
+/**
+ * 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.
+ * @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, 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, 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);
+	ret = ttm_bo_init_reserved(bdev, bo, type, placement, alignment, &ctx,
+				   sg, resv, destroy);
 	if (ret)
 		return ret;
 
@@ -1009,7 +1068,7 @@ int ttm_bo_init(struct ttm_device *bdev,
 
 	return 0;
 }
-EXPORT_SYMBOL(ttm_bo_init);
+EXPORT_SYMBOL(ttm_bo_init_validate);
 
 /*
  * buffer object vm functions.