[PATCH RFC v4 01/16] drm: Add drm_minor_for_each

[Kenny Ho <Kenny.Ho@xxxxxxx>]

To allow other subsystems to iterate through all stored DRM minors and
act upon them.

Also exposes drm_minor_acquire and drm_minor_release for other subsystem
to handle drm_minor.  DRM cgroup controller is the initial consumer of
this new features.

Change-Id: I7c4b67ce6b31f06d1037b03435386ff5b8144ca5
Signed-off-by: Kenny Ho <Kenny.Ho@xxxxxxx>
---
 drivers/gpu/drm/drm_drv.c      | 19 +++++++++++++++++++
 drivers/gpu/drm/drm_internal.h |  4 ----
 include/drm/drm_drv.h          |  4 ++++
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 862621494a93..000cddabd970 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -254,11 +254,13 @@ struct drm_minor *drm_minor_acquire(unsigned int minor_id)
 
 	return minor;
 }
+EXPORT_SYMBOL(drm_minor_acquire);
 
 void drm_minor_release(struct drm_minor *minor)
 {
 	drm_dev_put(minor->dev);
 }
+EXPORT_SYMBOL(drm_minor_release);
 
 /**
  * DOC: driver instance overview
@@ -1078,6 +1080,23 @@ int drm_dev_set_unique(struct drm_device *dev, const char *name)
 }
 EXPORT_SYMBOL(drm_dev_set_unique);
 
+/**
+ * drm_minor_for_each - Iterate through all stored DRM minors
+ * @fn: Function to be called for each pointer.
+ * @data: Data passed to callback function.
+ *
+ * The callback function will be called for each @drm_minor entry, passing
+ * the minor, the entry and @data.
+ *
+ * If @fn returns anything other than %0, the iteration stops and that
+ * value is returned from this function.
+ */
+int drm_minor_for_each(int (*fn)(int id, void *p, void *data), void *data)
+{
+	return idr_for_each(&drm_minors_idr, fn, data);
+}
+EXPORT_SYMBOL(drm_minor_for_each);
+
 /*
  * DRM Core
  * The DRM core module initializes all global DRM objects and makes them
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index e19ac7ca602d..6bfad76f8e78 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -54,10 +54,6 @@ void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv);
 void drm_prime_remove_buf_handle_locked(struct drm_prime_file_private *prime_fpriv,
 					struct dma_buf *dma_buf);
 
-/* drm_drv.c */
-struct drm_minor *drm_minor_acquire(unsigned int minor_id);
-void drm_minor_release(struct drm_minor *minor);
-
 /* drm_vblank.c */
 void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe);
 void drm_vblank_cleanup(struct drm_device *dev);
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 68ca736c548d..24f8d054c570 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -799,5 +799,9 @@ static inline bool drm_drv_uses_atomic_modeset(struct drm_device *dev)
 
 int drm_dev_set_unique(struct drm_device *dev, const char *name);
 
+int drm_minor_for_each(int (*fn)(int id, void *p, void *data), void *data);
+
+struct drm_minor *drm_minor_acquire(unsigned int minor_id);
+void drm_minor_release(struct drm_minor *minor);
 
 #endif
-- 
2.22.0