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>
[jy0922.shim: fix up fuzz to apply]
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Change-Id: Iffcd6e849d13b7c79bbd6571c92bcdd4f45f3a69

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index bbe34ec..a3ce359 100644 (file)
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -92,7 +92,7 @@ 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);
@@ -252,10 +252,10 @@ 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);
 }
@@ -321,16 +321,16 @@ 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;
@@ -501,8 +501,8 @@ 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;
@@ -524,8 +524,8 @@ 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);
 
        DRM_DEBUG("%s:hdl[%d]obj[0x%x]name[%d]\n",
@@ -552,11 +552,11 @@ 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 5351e81..5329832 100644 (file)
--- 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 8fe82bb..802b698 100644 (file)
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1242,7 +1242,7 @@ 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;