drm/prime: shrink critical section protected by prime lock

When exporting a gem object as a dma-buf the critical section for the
per-fd prime lock is just the adding (and in case of errors, removing)
of the handle to the per-fd lookup cache.

So restrict the critical section to just that part of the function.

This simplifies later reordering.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index c2d6d54e10e0..cb0451679e81 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -310,7 +310,6 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev,
         if (!obj)
                 return -ENOENT;
 
-        mutex_lock(&file_priv->prime.lock);
         /* re-export the original imported object */
         if (obj->import_attach) {
                 dmabuf = obj->import_attach->dmabuf;
@@ -332,6 +331,7 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev,
         }
         obj->export_dma_buf = dmabuf;
 
+        mutex_lock(&file_priv->prime.lock);
         /* if we've exported this buffer the cheat and add it to the import list
          * so we get the correct handle back
          */
@@ -363,13 +363,13 @@ out_have_obj:
 fail_rm_handle:
         drm_prime_remove_buf_handle_locked(&file_priv->prime,
                                            dmabuf);
+        mutex_unlock(&file_priv->prime.lock);
 fail_put_dmabuf:
         /* clear NOT to be checked when releasing dma_buf */
         obj->export_dma_buf = NULL;
         dma_buf_put(dmabuf);
 out:
         drm_gem_object_unreference_unlocked(obj);
-        mutex_unlock(&file_priv->prime.lock);
         return ret;
 }
 EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);