diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index d384139973790e..f5efbb836e5cce 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -293,15 +293,23 @@ i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj) static struct i915_mmu_notifier * i915_mmu_notifier_find(struct i915_mm_struct *mm) { - if (mm->mn == NULL) { - down_write(&mm->mm->mmap_sem); - mutex_lock(&to_i915(mm->dev)->mm_lock); - if (mm->mn == NULL) - mm->mn = i915_mmu_notifier_create(mm->mm); - mutex_unlock(&to_i915(mm->dev)->mm_lock); - up_write(&mm->mm->mmap_sem); + struct i915_mmu_notifier *mn = mm->mn; + + mn = mm->mn; + if (mn) + return mn; + + down_write(&mm->mm->mmap_sem); + mutex_lock(&to_i915(mm->dev)->mm_lock); + if ((mn = mm->mn) == NULL) { + mn = i915_mmu_notifier_create(mm->mm); + if (!IS_ERR(mn)) + mm->mn = mn; } - return mm->mn; + mutex_unlock(&to_i915(mm->dev)->mm_lock); + up_write(&mm->mm->mmap_sem); + + return mn; } static int