drm/nouveau: Implement weak channel references.

nouveau_channel_ref() takes a "weak" channel reference that doesn't
prevent the hardware channel resources from being released, it just
keeps the channel data structure alive.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h
index e6708be58bc..d152bc334fd 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -165,7 +165,11 @@ struct nouveau_channel {
         struct drm_device *dev;
         int id;
 
-        atomic_t refcount;
+        /* references to the channel data structure */
+        struct kref ref;
+        /* users of the hardware channel resources, the hardware
+         * context will be kicked off when it reaches zero. */
+        atomic_t users;
         struct mutex mutex;
 
         /* owner of this fifo */
@@ -808,6 +812,8 @@ extern struct nouveau_channel *
 nouveau_channel_get(struct drm_device *, struct drm_file *, int id);
 extern void nouveau_channel_put_unlocked(struct nouveau_channel **);
 extern void nouveau_channel_put(struct nouveau_channel **);
+extern void nouveau_channel_ref(struct nouveau_channel *chan,
+                                struct nouveau_channel **pchan);
 
 /* nouveau_object.c */
 extern int  nouveau_gpuobj_early_init(struct drm_device *);