This is a note to let you know that I've just added the patch titled
drm/i915: Only copy back the modified fields to userspace from execbuffer
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-only-copy-back-the-modified-fields-to-userspace-from-execbuffer.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9aab8bff7aa3bee567213ad3c1fdfb217bb980a2 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Fri, 23 May 2014 10:45:52 +0100
Subject: drm/i915: Only copy back the modified fields to userspace from execbuffer
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 54 +++++++++++++++++------------
1 file changed, 32 insertions(+), 22 deletions(-)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -635,9 +635,9 @@ i915_gem_execbuffer_relocate_slow(struct
* 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;
@@ -1151,18 +1151,21 @@ i915_gem_execbuffer(struct drm_device *d
ret = i915_gem_do_execbuffer(dev, data, file, &exec2, exec2_list);
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;
+ }
}
}
@@ -1208,14 +1211,21 @@ i915_gem_execbuffer2(struct drm_device *
ret = i915_gem_do_execbuffer(dev, data, file, args, exec2_list);
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;
+ }
}
}
Patches currently in stable-queue which might be from chris@xxxxxxxxxxxxxxxxxx are
queue-3.10/drm-i915-only-copy-back-the-modified-fields-to-userspace-from-execbuffer.patch
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