[Intel-gfx] [PATCH 10/12] drm/i915: Introduce dedicated object VMA iterator

[Tvrtko Ursulin]

On 02/02/16 12:58, Chris Wilson wrote:
> On Tue, Feb 02, 2016 at 12:10:19PM +0000, Tvrtko Ursulin wrote:
>> On 02/02/16 11:36, Chris Wilson wrote:
>>> #define list_for_each_entry_check(pos, list, member, lock) \
>>> for (typeof(*lock) == typeof(struct mutex) ? assert_lockdep_held(lock) : assert_spin_locked(lock); \
>>>       pos = list_first_entry(head, typeof(*pos), member); \
>>>       &pos->member != (head); \
>>>       pos = list_next_entry(pos, member))
>>>
>>> #define i915_gem_object_for_each_vma(vma, obj) \
>>> 	list_for_each_entry_check(vma, &(obj)->vma_list, vma_link, &(obj)->base.dev->struct_mutex)
>>> 	
>>> could be lifted easily, and makes i915_gem_object_for_each_vma() easier
>>> to understand (i.e. serves better as documentation).
>>
>> Don't know, needs buy-in from the relevant people, and depends on
>> how useful to outside of i915 it would be. And if you can make
>> lockdep_assert_held work in this context.
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 4004a7cf8db4..931684a74533 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -140,7 +140,7 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
>                     obj->madv == I915_MADV_DONTNEED ? " purgeable" : "");
>          if (obj->base.name)
>                  seq_printf(m, " (name: %d)", obj->base.name);
> -       list_for_each_entry(vma, &obj->vma_list, obj_link) {
> +       i915_gem_object_for_each_vma(vma, obj) {
>                  if (vma->pin_count > 0)
>                          pin_count++;
>          }
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 31487aa11977..574e45ab43cb 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -3565,4 +3565,36 @@ int remap_io_mapping(struct vm_area_struct *vma,
>                       unsigned long addr, unsigned long pfn, unsigned long size,
>                       struct io_mapping *iomap);
>
> +static __always_inline void __list_check_mutex(struct mutex *lock)
> +{
> +       lockdep_assert_held(lock);
> +}
> +
> +static __always_inline void __list_check_spin(struct spinlock *lock)
> +{
> +        assert_spin_locked(lock);
> +}
> +
> +static __always_inline void __list_check_bug(void *_lock)
> +{
> +       BUILD_BUG_ON("unknown lock type");
> +}
> +
> +#define __list_check(lock) \
> +       ({ __builtin_types_compatible_p(typeof(*lock), struct mutex) ? \
> +        __list_check_mutex((struct mutex *)lock) : \
> +        __builtin_types_compatible_p(typeof(*lock), struct spinlock) ? \
> +        __list_check_spin((struct spinlock *)lock) : \
> +        __list_check_bug(lock); \
> +        0; })
> +
> +#define list_for_each_entry_check(pos, head, member, lock) \
> +       for (__list_check(lock), \
> +            pos = list_first_entry(head, typeof(*pos), member); \
> +            &pos->member != (head); \
> +            pos = list_next_entry(pos, member))
> +
> +#define i915_gem_object_for_each_vma(vma, obj) \
> +       list_for_each_entry_check(vma, &(obj)->vma_list, obj_link, &(obj)->base.dev->struct_mutex)
> +
>   #endif

Nice! Want to take it over? ;)

Regards,

Tvrtko