drm/gem: switch dev->object_name_lock to a mutex

I want to wrap the creation of a dma-buf from a gem object in it,
so that the obj->export_dma_buf cache can be atomically filled in.

Instead of creating a new mutex just for that variable I've figured
I can reuse the existing dev->object_name_lock, especially since
the new semantics will exactly mirror the flink obj->name already
protected by that lock.

v2: idr_preload/idr_preload_end is now an atomic section, so need to
move the mutex locking outside.

[airlied: fix up conflict with patch to make debugfs use lock]

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

3 files changed, 12 insertions, 12 deletions

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 52548fd34b15..adb9eda4fa1a 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -93,7 +93,7 @@ drm_gem_init(struct drm_device *dev)
 {
         struct drm_gem_mm *mm;
 
-        spin_lock_init(&dev->object_name_lock);
+        mutex_init(&dev->object_name_lock);
         idr_init(&dev->object_name_idr);
 
         mm = kzalloc(sizeof(struct drm_gem_mm), GFP_KERNEL);
@@ -243,10 +243,10 @@ drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
         * checked for a name
         */
 
-        spin_lock(&obj->dev->object_name_lock);
+        mutex_lock(&obj->dev->object_name_lock);
         if (--obj->handle_count == 0)
                 drm_gem_object_handle_free(obj);
-        spin_unlock(&obj->dev->object_name_lock);
+        mutex_unlock(&obj->dev->object_name_lock);
 
         drm_gem_object_unreference_unlocked(obj);
 }
@@ -324,16 +324,16 @@ drm_gem_handle_create(struct drm_file *file_priv,
          * Get the user-visible handle using idr.  Preload and perform
          * allocation under our spinlock.
          */
+        mutex_lock(&dev->object_name_lock);
         idr_preload(GFP_KERNEL);
-        spin_lock(&dev->object_name_lock);
         spin_lock(&file_priv->table_lock);
 
         ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT);
         drm_gem_object_reference(obj);
         obj->handle_count++;
         spin_unlock(&file_priv->table_lock);
-        spin_unlock(&dev->object_name_lock);
         idr_preload_end();
+        mutex_unlock(&dev->object_name_lock);
         if (ret < 0) {
                 drm_gem_object_handle_unreference_unlocked(obj);
                 return ret;
@@ -578,8 +578,8 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data,
         if (obj == NULL)
                 return -ENOENT;
 
+        mutex_lock(&dev->object_name_lock);
         idr_preload(GFP_KERNEL);
-        spin_lock(&dev->object_name_lock);
         /* prevent races with concurrent gem_close. */
         if (obj->handle_count == 0) {
                 ret = -ENOENT;
@@ -601,8 +601,8 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data,
         ret = 0;
 
 err:
-        spin_unlock(&dev->object_name_lock);
         idr_preload_end();
+        mutex_unlock(&dev->object_name_lock);
         drm_gem_object_unreference_unlocked(obj);
         return ret;
 }
@@ -625,11 +625,11 @@ drm_gem_open_ioctl(struct drm_device *dev, void *data,
         if (!(dev->driver->driver_features & DRIVER_GEM))
                 return -ENODEV;
 
-        spin_lock(&dev->object_name_lock);
+        mutex_lock(&dev->object_name_lock);
         obj = idr_find(&dev->object_name_idr, (int) args->name);
         if (obj)
                 drm_gem_object_reference(obj);
-        spin_unlock(&dev->object_name_lock);
+        mutex_unlock(&dev->object_name_lock);
         if (!obj)
                 return -ENOENT;
 
diff --git a/drivers/gpu/drm/drm_info.c b/drivers/gpu/drm/drm_info.c
index 5351e811c421..53298320080b 100644
--- a/drivers/gpu/drm/drm_info.c
+++ b/drivers/gpu/drm/drm_info.c
@@ -219,9 +219,9 @@ int drm_gem_name_info(struct seq_file *m, void *data)
 
         seq_printf(m, "  name     size handles refcount\n");
 
-        spin_lock(&dev->object_name_lock);
+        mutex_lock(&dev->object_name_lock);
         idr_for_each(&dev->object_name_idr, drm_gem_one_name_info, m);
-        spin_unlock(&dev->object_name_lock);
+        mutex_unlock(&dev->object_name_lock);
 
         return 0;
 }
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 7782dbbbe126..bf058470a0fd 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1196,7 +1196,7 @@ struct drm_device {
 
         /** \name GEM information */
         /*@{ */
-        spinlock_t object_name_lock;
+        struct mutex object_name_lock;
         struct idr object_name_idr;
         /*@} */
         int switch_power_state;