drm/i915: Fix lock order reversal with cliprects and cmdbuf in non-DRI2 paths.

This introduces allocation in the batch submission path that wasn't there
previously, but these are compatibility paths so we care about simplicity
more than performance.

kernel.org bug #12419.

Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Keith Packard <keithp@keithp.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 23 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 010af908bdb6..2bda15197cce 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2891,11 +2891,10 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
 static int
 i915_dispatch_gem_execbuffer(struct drm_device *dev,
                               struct drm_i915_gem_execbuffer *exec,
+                              struct drm_clip_rect *cliprects,
                               uint64_t exec_offset)
 {
         drm_i915_private_t *dev_priv = dev->dev_private;
-        struct drm_clip_rect __user *boxes = (struct drm_clip_rect __user *)
-                                             (uintptr_t) exec->cliprects_ptr;
         int nbox = exec->num_cliprects;
         int i = 0, count;
         uint32_t        exec_start, exec_len;
@@ -2916,7 +2915,7 @@ i915_dispatch_gem_execbuffer(struct drm_device *dev,
 
         for (i = 0; i < count; i++) {
                 if (i < nbox) {
-                        int ret = i915_emit_box(dev, boxes, i,
+                        int ret = i915_emit_box(dev, cliprects, i,
                                                 exec->DR1, exec->DR4);
                         if (ret)
                                 return ret;
@@ -2983,6 +2982,7 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
         struct drm_gem_object **object_list = NULL;
         struct drm_gem_object *batch_obj;
         struct drm_i915_gem_object *obj_priv;
+        struct drm_clip_rect *cliprects = NULL;
         int ret, i, pinned = 0;
         uint64_t exec_offset;
         uint32_t seqno, flush_domains;
@@ -3019,6 +3019,23 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
                 goto pre_mutex_err;
         }
 
+        if (args->num_cliprects != 0) {
+                cliprects = drm_calloc(args->num_cliprects, sizeof(*cliprects),
+                                       DRM_MEM_DRIVER);
+                if (cliprects == NULL)
+                        goto pre_mutex_err;
+
+                ret = copy_from_user(cliprects,
+                                     (struct drm_clip_rect __user *)
+                                     (uintptr_t) args->cliprects_ptr,
+                                     sizeof(*cliprects) * args->num_cliprects);
+                if (ret != 0) {
+                        DRM_ERROR("copy %d cliprects failed: %d\n",
+                                  args->num_cliprects, ret);
+                        goto pre_mutex_err;
+                }
+        }
+
         mutex_lock(&dev->struct_mutex);
 
         i915_verify_inactive(dev, __FILE__, __LINE__);
@@ -3155,7 +3172,7 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
 #endif
 
         /* Exec the batchbuffer */
-        ret = i915_dispatch_gem_execbuffer(dev, args, exec_offset);
+        ret = i915_dispatch_gem_execbuffer(dev, args, cliprects, exec_offset);
         if (ret) {
                 DRM_ERROR("dispatch failed %d\n", ret);
                 goto err;
@@ -3224,6 +3241,8 @@ pre_mutex_err:
                  DRM_MEM_DRIVER);
         drm_free(exec_list, sizeof(*exec_list) * args->buffer_count,
                  DRM_MEM_DRIVER);
+        drm_free(cliprects, sizeof(*cliprects) * args->num_cliprects,
+                 DRM_MEM_DRIVER);
 
         return ret;
 }