Merge branch 'fixes-2.6.39' into for-2.6.40

1 files changed, 17 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 7ff7f93..20a4cc5 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -367,6 +367,10 @@ i915_gem_execbuffer_relocate_entry(struct drm_i915_gem_object *obj,
 		uint32_t __iomem *reloc_entry;
 		void __iomem *reloc_page;
 
+		/* We can't wait for rendering with pagefaults disabled */
+		if (obj->active && in_atomic())
+			return -EFAULT;
+
 		ret = i915_gem_object_set_to_gtt_domain(obj, 1);
 		if (ret)
 			return ret;
@@ -440,15 +444,24 @@ i915_gem_execbuffer_relocate(struct drm_device *dev,
 			     struct list_head *objects)
 {
 	struct drm_i915_gem_object *obj;
-	int ret;
-
+	int ret = 0;
+
+	/* This is the fast path and we cannot handle a pagefault whilst
+	 * holding the struct mutex lest the user pass in the relocations
+	 * contained within a mmaped bo. For in such a case we, the page
+	 * fault handler would call i915_gem_fault() and we would try to
+	 * acquire the struct mutex again. Obviously this is bad and so
+	 * lockdep complains vehemently.
+	 */
+	pagefault_disable();
 	list_for_each_entry(obj, objects, exec_list) {
 		ret = i915_gem_execbuffer_relocate_object(obj, eb);
 		if (ret)
-			return ret;
+			break;
 	}
+	pagefault_enable();
 
-	return 0;
+	return ret;
 }
 
 static int