Re: [PATCH 1/3] drm/ttm: split BO structure initialization into a separate function

["Nicolai Hähnle" <nicolai.haehnle-5C7GfCeVMHo@public.gmane.org>]

On 15.02.2017 04:16, zhoucm1 wrote:
>
>
> On 2017年02月14日 18:37, Nicolai Hähnle wrote:
>> From: Nicolai Hähnle <nicolai.haehnle@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@amd.com>
>> ---
>>   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;
>>       }
>> @@ -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);
> if (ret && !resv), we should call
> reservation_object_fini(&bo->ttm_resv), right?

FWIW, you were right about this (and also mutex_destroy needs to be 
called for wu_mutex, etc.). But I'm following Christian's suggestion of 
having the caller use ttm_bo_unref for error cleanup, so all this error 
cleanup needn't be duplicated.

Cheers,
Nicola
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