Am 14.02.2017 um 11:37 schrieb Nicolai Hähnle:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>
> Allow callers to opt out of calling ttm_bo_validate immediately. This
> allows more flexibility in how locking of the reservation object is
> done, which is needed to fix a locking bug (destroy locked mutex)
> in amdgpu.
>
> Signed-off-by: Nicolai Hähnle <nicolai.haehnle at amd.com>
Please squash that into your other patch. It fixes another bug, but I
don't think fixing one bug just to run into another is really a good idea.
Additional to that one comment below.
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 62 +++++++++++++++++++++++++++++---------------
> include/drm/ttm/ttm_bo_api.h | 45 ++++++++++++++++++++++++++++++++
> 2 files changed, 86 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 76bee42..ce4c0f5 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -1120,41 +1120,30 @@ 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_top(struct ttm_bo_device *bdev,
> + struct ttm_buffer_object *bo,
> + unsigned long size,
> + enum ttm_bo_type type,
> + uint32_t page_alignment,
> + 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;
> struct ttm_mem_global *mem_glob = bdev->glob->mem_glob;
> - bool locked;
>
> ret = ttm_mem_global_alloc(mem_glob, acc_size, false, false);
> if (ret) {
> pr_err("Out of kernel memory\n");
> - if (destroy)
> - (*destroy)(bo);
> - else
> - kfree(bo);
> return -ENOMEM;
> }
>
> num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
> if (num_pages == 0) {
> pr_err("Illegal buffer object size\n");
> - if (destroy)
> - (*destroy)(bo);
> - else
> - kfree(bo);
> ttm_mem_global_free(mem_glob, acc_size);
> return -EINVAL;
> }
I would move those checks after all the field initializations. This way
the structure has at least a valid content and we can safely use
ttm_bo_unref on it.
Regards,
Christian.
> @@ -1204,6 +1193,37 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
> ret = drm_vma_offset_add(&bdev->vma_manager, &bo->vma_node,
> bo->mem.num_pages);
>
> + return ret;
> +}
> +EXPORT_SYMBOL(ttm_bo_init_top);
> +
> +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 *))
> +{
> + bool locked;
> + int ret;
> +
> + ret = ttm_bo_init_top(bdev, bo, size, type, page_alignment,
> + persistent_swap_storage, acc_size, sg, resv,
> + destroy);
> + if (ret) {
> + if (destroy)
> + (*destroy)(bo);
> + else
> + kfree(bo);
> + return ret;
> + }
> +
> /* passed reservation objects should already be locked,
> * since otherwise lockdep will be angered in radeon.
> */
> diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> index f195899..d44b8e4 100644
> --- a/include/drm/ttm/ttm_bo_api.h
> +++ b/include/drm/ttm/ttm_bo_api.h
> @@ -453,6 +453,51 @@ size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
> unsigned struct_size);
>
> /**
> + * ttm_bo_init_top
> + *
> + * @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.
> + * @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.
> + *
> + * Unlike ttm_bo_init, @bo is not validated, and when an error is returned,
> + * the caller is responsible for freeing @bo (but the setup performed by
> + * ttm_bo_init_top itself is cleaned up).
> + *
> + * On successful return, the object kref and list_kref are set to 1.
> + *
> + * Returns
> + * -ENOMEM: Out of memory.
> + * -EINVAL: Invalid buffer size.
> + */
> +
> +extern int ttm_bo_init_top(struct ttm_bo_device *bdev,
> + struct ttm_buffer_object *bo,
> + unsigned long size,
> + enum ttm_bo_type type,
> + uint32_t page_alignment,
> + 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.
