[patch] i915: return -EFAULT if copy_to_user fails

[Dan Carpenter]

copy_to_user returns the number of bytes remaining to be copied, but we
want to return a negative error code here.  These are returned to
userspace.

Signed-off-by: Dan Carpenter <error27 at gmail.com>

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 59a2bf8..5fd876e 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -608,8 +608,10 @@ static int i915_batchbuffer(struct drm_device *dev, void 
*data,
                ret = copy_from_user(cliprects, batch->cliprects,
                                     batch->num_cliprects *
                                     sizeof(struct drm_clip_rect));
-               if (ret != 0)
+               if (ret != 0) {
+                       ret = -EFAULT;
                        goto fail_free;
+               }
        }

        mutex_lock(&dev->struct_mutex);
@@ -650,8 +652,10 @@ static int i915_cmdbuffer(struct drm_device *dev, void 
*data,
                return -ENOMEM;

        ret = copy_from_user(batch_data, cmdbuf->buf, cmdbuf->sz);
-       if (ret != 0)
+       if (ret != 0) {
+               ret = -EFAULT;
                goto fail_batch_free;
+       }

        if (cmdbuf->num_cliprects) {
                cliprects = kcalloc(cmdbuf->num_cliprects,
@@ -664,8 +668,10 @@ static int i915_cmdbuffer(struct drm_device *dev, void 
*data,
                ret = copy_from_user(cliprects, cmdbuf->cliprects,
                                     cmdbuf->num_cliprects *
                                     sizeof(struct drm_clip_rect));
-               if (ret != 0)
+               if (ret != 0) {
+                       ret = -EFAULT;
                        goto fail_clip_free;
+               }
        }

        mutex_lock(&dev->struct_mutex);