[Intel-gfx] [PATCH 17/42] drm/i915: Pass around sg_table to get_pages/put_pages backend

[Tvrtko Ursulin]

On 14/10/2016 10:43, Chris Wilson wrote:
> On Fri, Oct 14, 2016 at 10:28:42AM +0100, Tvrtko Ursulin wrote:
>>   diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>>   index 3c22d49005fe..271e63c8f037 100644
>>   --- a/drivers/gpu/drm/i915/i915_drv.h
>>   +++ b/drivers/gpu/drm/i915/i915_drv.h
>>   @@ -2175,8 +2175,8 @@ struct drm_i915_gem_object_ops {
>>            * being released or under memory pressure (where we attempt to
>>            * reap pages for the shrinker).
>>            */
>>   -       int (*get_pages)(struct drm_i915_gem_object *);
>>   -       void (*put_pages)(struct drm_i915_gem_object *);
>>   +       struct sg_table *(*get_pages)(struct drm_i915_gem_object *);
>>   +       void (*put_pages)(struct drm_i915_gem_object *, struct sg_table *);
>>
>>     Idea is that put_pages vfunc does not need struct mutex?  Or it acquires
>>     it on demand inside it, which means struct mutex will nest inside the
>>     mm.lock?
> Right, it loses the mutex within get/put pages and I am no longer
> concerned about the number of workers. Though that is mainly because of
> another patch to improve execbuf + userptr workloads.

Is that other patch before or after this one? Or in a different series 
altogether? In any case, why should this change be in this patch, 
especially when it is not commented anywhere?

Regards,

Tvrtko