drm/i915/userptr: Store i915 backpointer for i915_mm_struct

Since we only ever use the drm_i915_private from the stored
i915_mm_struct->dev, save some electrons by storing the right
backpointer.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459864801-28606-3-git-send-email-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 3e31f59..bebaf75 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -34,7 +34,7 @@
 
 struct i915_mm_struct {
        struct mm_struct *mm;
-       struct drm_device *dev;
+       struct drm_i915_private *i915;
        struct i915_mmu_notifier *mn;
        struct hlist_node node;
        struct kref kref;
@@ -250,13 +250,13 @@ i915_mmu_notifier_find(struct i915_mm_struct *mm)
                return mn;
 
        down_write(&mm->mm->mmap_sem);
-       mutex_lock(&to_i915(mm->dev)->mm_lock);
+       mutex_lock(&mm->i915->mm_lock);
        if ((mn = mm->mn) == NULL) {
                mn = i915_mmu_notifier_create(mm->mm);
                if (!IS_ERR(mn))
                        mm->mn = mn;
        }
-       mutex_unlock(&to_i915(mm->dev)->mm_lock);
+       mutex_unlock(&mm->i915->mm_lock);
        up_write(&mm->mm->mmap_sem);
 
        return mn;
@@ -373,7 +373,7 @@ i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj)
                }
 
                kref_init(&mm->kref);
-               mm->dev = obj->base.dev;
+               mm->i915 = to_i915(obj->base.dev);
 
                mm->mm = current->mm;
                atomic_inc(&current->mm->mm_count);
@@ -408,7 +408,7 @@ __i915_mm_struct_free(struct kref *kref)
 
        /* Protected by dev_priv->mm_lock */
        hash_del(&mm->node);
-       mutex_unlock(&to_i915(mm->dev)->mm_lock);
+       mutex_unlock(&mm->i915->mm_lock);
 
        INIT_WORK(&mm->work, __i915_mm_struct_free__worker);
        schedule_work(&mm->work);