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authorChris Wilson <chris@chris-wilson.co.uk>2014-05-23 10:45:52 +0100
committerShow Liu <show.liu@linaro.org>2014-06-18 12:05:24 +0800
commit1aae040d917033f3d0413ea48991011b3928be7a (patch)
treed3471343f37e9262e89e675e14070b1394c81d91
parent9166844797dcd1b3d5573828d9ec47d2fbcfe938 (diff)
downloadlinaro-lsk-1aae040d917033f3d0413ea48991011b3928be7a.tar.gz
drm/i915: Only copy back the modified fields to userspace from execbuffer
commit 9aab8bff7aa3bee567213ad3c1fdfb217bb980a2 upstream. We only want to modifiy a single field in the userspace view of the execbuffer command buffer, so explicitly change that rather than copy everything back again. This serves two purposes: 1. The single fields are much cheaper to copy (constant size so the copy uses special case code) and much smaller than the whole array. 2. We modify the array for internal use that need to be masked from the user. Note: We need this backported since without it the next bugfix will blow up when userspace recycles batchbuffers and relocations. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/gpu/drm/i915/i915_gem_execbuffer.c54
1 files changed, 32 insertions, 22 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index d269ecf46e2..768e6665e4e 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -766,9 +766,9 @@ i915_gem_execbuffer_relocate_slow(struct drm_device *dev,
* relocations were valid.
*/
for (j = 0; j < exec[i].relocation_count; j++) {
- if (copy_to_user(&user_relocs[j].presumed_offset,
- &invalid_offset,
- sizeof(invalid_offset))) {
+ if (__copy_to_user(&user_relocs[j].presumed_offset,
+ &invalid_offset,
+ sizeof(invalid_offset))) {
ret = -EFAULT;
mutex_lock(&dev->struct_mutex);
goto err;
@@ -1329,18 +1329,21 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
ret = i915_gem_do_execbuffer(dev, data, file, &exec2, exec2_list,
&dev_priv->gtt.base);
if (!ret) {
+ struct drm_i915_gem_exec_object __user *user_exec_list =
+ to_user_ptr(args->buffers_ptr);
+
/* Copy the new buffer offsets back to the user's exec list. */
- for (i = 0; i < args->buffer_count; i++)
- exec_list[i].offset = exec2_list[i].offset;
- /* ... and back out to userspace */
- ret = copy_to_user(to_user_ptr(args->buffers_ptr),
- exec_list,
- sizeof(*exec_list) * args->buffer_count);
- if (ret) {
- ret = -EFAULT;
- DRM_DEBUG("failed to copy %d exec entries "
- "back to user (%d)\n",
- args->buffer_count, ret);
+ for (i = 0; i < args->buffer_count; i++) {
+ ret = __copy_to_user(&user_exec_list[i].offset,
+ &exec2_list[i].offset,
+ sizeof(user_exec_list[i].offset));
+ if (ret) {
+ ret = -EFAULT;
+ DRM_DEBUG("failed to copy %d exec entries "
+ "back to user (%d)\n",
+ args->buffer_count, ret);
+ break;
+ }
}
}
@@ -1388,14 +1391,21 @@ i915_gem_execbuffer2(struct drm_device *dev, void *data,
&dev_priv->gtt.base);
if (!ret) {
/* Copy the new buffer offsets back to the user's exec list. */
- ret = copy_to_user(to_user_ptr(args->buffers_ptr),
- exec2_list,
- sizeof(*exec2_list) * args->buffer_count);
- if (ret) {
- ret = -EFAULT;
- DRM_DEBUG("failed to copy %d exec entries "
- "back to user (%d)\n",
- args->buffer_count, ret);
+ struct drm_i915_gem_exec_object2 *user_exec_list =
+ to_user_ptr(args->buffers_ptr);
+ int i;
+
+ for (i = 0; i < args->buffer_count; i++) {
+ ret = __copy_to_user(&user_exec_list[i].offset,
+ &exec2_list[i].offset,
+ sizeof(user_exec_list[i].offset));
+ if (ret) {
+ ret = -EFAULT;
+ DRM_DEBUG("failed to copy %d exec entries "
+ "back to user\n",
+ args->buffer_count);
+ break;
+ }
}
}