Merge branches 'hfi1' and 'iw_cxgb4' into k.o/for-4.7

[cascardo/linux.git] / drivers / gpu / drm / i915 / i915_gem_userptr.c

diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 18ba813..4d30b60 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -501,19 +501,24 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
        if (pvec != NULL) {
                struct mm_struct *mm = obj->userptr.mm->mm;
 
-               down_read(&mm->mmap_sem);
-               while (pinned < npages) {
-                       ret = get_user_pages_remote(work->task, mm,
-                                       obj->userptr.ptr + pinned * PAGE_SIZE,
-                                       npages - pinned,
-                                       !obj->userptr.read_only, 0,
-                                       pvec + pinned, NULL);
-                       if (ret < 0)
-                               break;
-
-                       pinned += ret;
+               ret = -EFAULT;
+               if (atomic_inc_not_zero(&mm->mm_users)) {
+                       down_read(&mm->mmap_sem);
+                       while (pinned < npages) {
+                               ret = get_user_pages_remote
+                                       (work->task, mm,
+                                        obj->userptr.ptr + pinned * PAGE_SIZE,
+                                        npages - pinned,
+                                        !obj->userptr.read_only, 0,
+                                        pvec + pinned, NULL);
+                               if (ret < 0)
+                                       break;
+
+                               pinned += ret;
+                       }
+                       up_read(&mm->mmap_sem);
+                       mmput(mm);
                }
-               up_read(&mm->mmap_sem);
        }
 
        mutex_lock(&dev->struct_mutex);