From: Nicolai Hähnle <nicolai.haeh...@amd.com>

This variant of ttm_bo_init returns the validated buffer object with
the reservation lock held when resv == NULL. This is convenient for
callers that want to use the BO immediately, e.g. for initializing its
contents.

Signed-off-by: Nicolai Hähnle <nicolai.haeh...@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 59 +++++++++++++++++++++++++++++++++-----------
 include/drm/ttm/ttm_bo_api.h | 54 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 98 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index c438b04..989b98b 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1119,18 +1119,18 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
 }
 EXPORT_SYMBOL(ttm_bo_validate);
 
-int ttm_bo_init(struct ttm_bo_device *bdev,
-               struct ttm_buffer_object *bo,
-               unsigned long size,
-               enum ttm_bo_type type,
-               struct ttm_placement *placement,
-               uint32_t page_alignment,
-               bool interruptible,
-               struct file *persistent_swap_storage,
-               size_t acc_size,
-               struct sg_table *sg,
-               struct reservation_object *resv,
-               void (*destroy) (struct ttm_buffer_object *))
+int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
+                        struct ttm_buffer_object *bo,
+                        unsigned long size,
+                        enum ttm_bo_type type,
+                        struct ttm_placement *placement,
+                        uint32_t page_alignment,
+                        bool interruptible,
+                        struct file *persistent_swap_storage,
+                        size_t acc_size,
+                        struct sg_table *sg,
+                        struct reservation_object *resv,
+                        void (*destroy) (struct ttm_buffer_object *))
 {
        int ret = 0;
        unsigned long num_pages;
@@ -1214,10 +1214,10 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
        if (likely(!ret))
                ret = ttm_bo_validate(bo, placement, interruptible, false);
 
-       if (!resv)
-               ttm_bo_unreserve(bo);
-
        if (unlikely(ret)) {
+               if (!resv)
+                       ttm_bo_unreserve(bo);
+
                ttm_bo_unref(&bo);
                return ret;
        }
@@ -1230,6 +1230,35 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 
        return ret;
 }
+EXPORT_SYMBOL(ttm_bo_init_reserved);
+
+int ttm_bo_init(struct ttm_bo_device *bdev,
+               struct ttm_buffer_object *bo,
+               unsigned long size,
+               enum ttm_bo_type type,
+               struct ttm_placement *placement,
+               uint32_t page_alignment,
+               bool interruptible,
+               struct file *persistent_swap_storage,
+               size_t acc_size,
+               struct sg_table *sg,
+               struct reservation_object *resv,
+               void (*destroy) (struct ttm_buffer_object *))
+{
+       int ret;
+
+       ret = ttm_bo_init_reserved(bdev, bo, size, type, placement,
+                                  page_alignment, interruptible,
+                                  persistent_swap_storage, acc_size,
+                                  sg, resv, destroy);
+       if (ret)
+               return ret;
+
+       if (!resv)
+               ttm_bo_unreserve(bo);
+
+       return 0;
+}
 EXPORT_SYMBOL(ttm_bo_init);
 
 size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index c0ebbd6..2d0f63e 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -453,6 +453,60 @@ size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
                           unsigned struct_size);
 
 /**
+ * ttm_bo_init_reserved
+ *
+ * @bdev: Pointer to a ttm_bo_device struct.
+ * @bo: Pointer to a ttm_buffer_object to be initialized.
+ * @size: Requested size of buffer object.
+ * @type: Requested type of buffer object.
+ * @flags: Initial placement flags.
+ * @page_alignment: Data alignment in pages.
+ * @interruptible: If needing to sleep to wait for GPU resources,
+ * sleep interruptible.
+ * @persistent_swap_storage: Usually the swap storage is deleted for buffers
+ * 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.
+ * @acc_size: Accounted size for this object.
+ * @resv: Pointer to a reservation_object, 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.
+ */
+
+extern int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
+                               struct ttm_buffer_object *bo,
+                               unsigned long size,
+                               enum ttm_bo_type type,
+                               struct ttm_placement *placement,
+                               uint32_t page_alignment,
+                               bool interrubtible,
+                               struct file *persistent_swap_storage,
+                               size_t acc_size,
+                               struct sg_table *sg,
+                               struct reservation_object *resv,
+                               void (*destroy) (struct ttm_buffer_object *));
+
+/**
  * ttm_bo_init
  *
  * @bdev: Pointer to a ttm_bo_device struct.
-- 
2.9.3

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