[05/18] drm/bochs: Don't grab dev->struct_mutex for in mmap offset ioctl
diff mbox

Message ID 1436477570-4936-6-git-send-email-daniel.vetter@ffwll.ch
State New
Headers show

Commit Message

Daniel Vetter July 9, 2015, 9:32 p.m. UTC
Since David Herrmann's mmap vma manager rework we don't need to grab
dev->struct_mutex any more to prevent races when looking up the mmap
offset. Drop it and instead don't forget to use the unref_unlocked
variant (since the drm core still cares).

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/bochs/bochs_mm.c | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

Comments

Thierry Reding Aug. 10, 2015, 10:45 a.m. UTC | #1
On Thu, Jul 09, 2015 at 11:32:37PM +0200, Daniel Vetter wrote:
> Since David Herrmann's mmap vma manager rework we don't need to grab
> dev->struct_mutex any more to prevent races when looking up the mmap
> offset. Drop it and instead don't forget to use the unref_unlocked
> variant (since the drm core still cares).
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  drivers/gpu/drm/bochs/bochs_mm.c | 16 ++++------------
>  1 file changed, 4 insertions(+), 12 deletions(-)

Reviewed-by: Thierry Reding <treding@nvidia.com>

Patch
diff mbox

diff --git a/drivers/gpu/drm/bochs/bochs_mm.c b/drivers/gpu/drm/bochs/bochs_mm.c
index 66286ff518d4..f69e6bf9bb0e 100644
--- a/drivers/gpu/drm/bochs/bochs_mm.c
+++ b/drivers/gpu/drm/bochs/bochs_mm.c
@@ -454,25 +454,17 @@  int bochs_dumb_mmap_offset(struct drm_file *file, struct drm_device *dev,
 			   uint32_t handle, uint64_t *offset)
 {
 	struct drm_gem_object *obj;
-	int ret;
 	struct bochs_bo *bo;
 
-	mutex_lock(&dev->struct_mutex);
 	obj = drm_gem_object_lookup(dev, file, handle);
-	if (obj == NULL) {
-		ret = -ENOENT;
-		goto out_unlock;
-	}
+	if (obj == NULL)
+		return -ENOENT;
 
 	bo = gem_to_bochs_bo(obj);
 	*offset = bochs_bo_mmap_offset(bo);
 
-	drm_gem_object_unreference(obj);
-	ret = 0;
-out_unlock:
-	mutex_unlock(&dev->struct_mutex);
-	return ret;
-
+	drm_gem_object_unreference_unlocked(obj);
+	return 0;
 }
 
 /* ---------------------------------------------------------------------- */