drm: extract legacy ctxbitmap flushing

The ctxbitmap code is only used by legacy drivers so lets try to keep it
as separated as possible. Furthermore, the locking is non-obvious and
kinda weird with ctxlist_mutex *and* struct_mutex. Keeping all ctxbitmap
access in one file is much easier to review and makes drm_release() more
readable.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>

3 files changed, 32 insertions, 19 deletions

diff --git a/drivers/gpu/drm/drm_context.c b/drivers/gpu/drm/drm_context.c
index a4b017b6849e..c045505978f1 100644
--- a/drivers/gpu/drm/drm_context.c
+++ b/drivers/gpu/drm/drm_context.c
@@ -111,6 +111,36 @@ void drm_ctxbitmap_cleanup(struct drm_device * dev)
         mutex_unlock(&dev->struct_mutex);
 }
 
+/**
+ * drm_ctxbitmap_flush() - Flush all contexts owned by a file
+ * @dev: DRM device to operate on
+ * @file: Open file to flush contexts for
+ *
+ * This iterates over all contexts on @dev and drops them if they're owned by
+ * @file. Note that after this call returns, new contexts might be added if
+ * the file is still alive.
+ */
+void drm_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file)
+{
+        struct drm_ctx_list *pos, *tmp;
+
+        mutex_lock(&dev->ctxlist_mutex);
+
+        list_for_each_entry_safe(pos, tmp, &dev->ctxlist, head) {
+                if (pos->tag == file &&
+                    pos->handle != DRM_KERNEL_CONTEXT) {
+                        if (dev->driver->context_dtor)
+                                dev->driver->context_dtor(dev, pos->handle);
+
+                        drm_ctxbitmap_free(dev, pos->handle);
+                        list_del(&pos->head);
+                        kfree(pos);
+                }
+        }
+
+        mutex_unlock(&dev->ctxlist_mutex);
+}
+
 /*@}*/
 
 /******************************************************************/
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index bc583fe51e45..55143f7747f3 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -457,25 +457,7 @@ int drm_release(struct inode *inode, struct file *filp)
         if (dev->driver->driver_features & DRIVER_GEM)
                 drm_gem_release(dev, file_priv);
 
-        mutex_lock(&dev->ctxlist_mutex);
-        if (!list_empty(&dev->ctxlist)) {
-                struct drm_ctx_list *pos, *n;
-
-                list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
-                        if (pos->tag == file_priv &&
-                            pos->handle != DRM_KERNEL_CONTEXT) {
-                                if (dev->driver->context_dtor)
-                                        dev->driver->context_dtor(dev,
-                                                                  pos->handle);
-
-                                drm_ctxbitmap_free(dev, pos->handle);
-
-                                list_del(&pos->head);
-                                kfree(pos);
-                        }
-                }
-        }
-        mutex_unlock(&dev->ctxlist_mutex);
+        drm_ctxbitmap_flush(dev, file_priv);
 
         mutex_lock(&dev->master_mutex);
 
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index d3d9be6b83ef..80889982d196 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1242,6 +1242,7 @@ extern int drm_rmctx(struct drm_device *dev, void *data,
 extern int drm_ctxbitmap_init(struct drm_device *dev);
 extern void drm_ctxbitmap_cleanup(struct drm_device *dev);
 extern void drm_ctxbitmap_free(struct drm_device *dev, int ctx_handle);
+extern void drm_ctxbitmap_flush(struct drm_device *dev, struct drm_file *file);
 
 extern int drm_setsareactx(struct drm_device *dev, void *data,
                            struct drm_file *file_priv);