1 files changed, 32 insertions, 21 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 2d4996de7331..4d712a4db63b 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -164,7 +164,6 @@ static struct i915_mmu_notifier *
 i915_mmu_notifier_create(struct mm_struct *mm)
 {
 	struct i915_mmu_notifier *mn;
-	int ret;
 
 	mn = kmalloc(sizeof(*mn), GFP_KERNEL);
 	if (mn == NULL)
@@ -179,14 +178,6 @@ i915_mmu_notifier_create(struct mm_struct *mm)
 		return ERR_PTR(-ENOMEM);
 	}
 
-	 /* Protected by mmap_sem (write-lock) */
-	ret = __mmu_notifier_register(&mn->mn, mm);
-	if (ret) {
-		destroy_workqueue(mn->wq);
-		kfree(mn);
-		return ERR_PTR(ret);
-	}
-
 	return mn;
 }
 
@@ -210,23 +201,40 @@ 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)
 {
-	struct i915_mmu_notifier *mn = mm->mn;
+	struct i915_mmu_notifier *mn;
+	int err = 0;
 
 	mn = mm->mn;
 	if (mn)
 		return mn;
 
+	mn = i915_mmu_notifier_create(mm->mm);
+	if (IS_ERR(mn))
+		err = PTR_ERR(mn);
+
 	down_write(&mm->mm->mmap_sem);
 	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;
+	if (mm->mn == NULL && !err) {
+		/* Protected by mmap_sem (write-lock) */
+		err = __mmu_notifier_register(&mn->mn, mm->mm);
+		if (!err) {
+			/* Protected by mm_lock */
+			mm->mn = fetch_and_zero(&mn);
+		}
+	} else {
+		/* someone else raced and successfully installed the mmu
+		 * notifier, we can cancel our own errors */
+		err = 0;
 	}
 	mutex_unlock(&mm->i915->mm_lock);
 	up_write(&mm->mm->mmap_sem);
 
-	return mn;
+	if (mn) {
+		destroy_workqueue(mn->wq);
+		kfree(mn);
+	}
+
+	return err ? ERR_PTR(err) : mm->mn;
 }
 
 static int
@@ -405,6 +413,7 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj,
 {
 	unsigned int max_segment = i915_sg_segment_size();
 	struct sg_table *st;
+	unsigned int sg_page_sizes;
 	int ret;
 
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
@@ -434,6 +443,10 @@ alloc_table:
 		return ERR_PTR(ret);
 	}
 
+	sg_page_sizes = i915_sg_page_sizes(st->sgl);
+
+	__i915_gem_object_set_pages(obj, st, sg_page_sizes);
+
 	return st;
 }
 
@@ -521,7 +534,6 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
 			pages = __i915_gem_userptr_alloc_pages(obj, pvec,
 							       npages);
 			if (!IS_ERR(pages)) {
-				__i915_gem_object_set_pages(obj, pages);
 				pinned = 0;
 				pages = NULL;
 			}
@@ -582,8 +594,7 @@ __i915_gem_userptr_get_pages_schedule(struct drm_i915_gem_object *obj)
 	return ERR_PTR(-EAGAIN);
 }
 
-static struct sg_table *
-i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
+static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 {
 	const int num_pages = obj->base.size >> PAGE_SHIFT;
 	struct mm_struct *mm = obj->userptr.mm->mm;
@@ -612,9 +623,9 @@ i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 	if (obj->userptr.work) {
 		/* active flag should still be held for the pending work */
 		if (IS_ERR(obj->userptr.work))
-			return ERR_CAST(obj->userptr.work);
+			return PTR_ERR(obj->userptr.work);
 		else
-			return ERR_PTR(-EAGAIN);
+			return -EAGAIN;
 	}
 
 	pvec = NULL;
@@ -650,7 +661,7 @@ i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 		release_pages(pvec, pinned, 0);
 	kvfree(pvec);
 
-	return pages;
+	return PTR_ERR_OR_ZERO(pages);
 }
 
 static void