drm/nouveau: Add unlocked variants of nouveau_channel_get/put.

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

drivers/gpu/drm/nouveau/nouveau_channel.c

@@ -237,34 +237,40 @@ nouveau_channel_alloc(struct drm_device *dev, struct nouveau_channel **chan_ret,
 	return 0;
 }
 
+struct nouveau_channel *
+nouveau_channel_get_unlocked(struct nouveau_channel *ref)
+{
+	if (likely(ref && atomic_inc_not_zero(&ref->refcount)))
+		return ref;
+
+	return NULL;
+}
+
 struct nouveau_channel *
 nouveau_channel_get(struct drm_device *dev, struct drm_file *file_priv, int id)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
-	struct nouveau_channel *chan = ERR_PTR(-ENODEV);
+	struct nouveau_channel *chan;
 	unsigned long flags;
 
 	spin_lock_irqsave(&dev_priv->channels.lock, flags);
-	chan = dev_priv->channels.ptr[id];
+	chan = nouveau_channel_get_unlocked(dev_priv->channels.ptr[id]);
+	spin_unlock_irqrestore(&dev_priv->channels.lock, flags);
 
-	if (unlikely(!chan || (file_priv && chan->file_priv != file_priv))) {
-		spin_unlock_irqrestore(&dev_priv->channels.lock, flags);
+	if (unlikely(!chan))
 		return ERR_PTR(-EINVAL);
-	}
 
-	if (unlikely(!atomic_inc_not_zero(&chan->refcount))) {
-		spin_unlock_irqrestore(&dev_priv->channels.lock, flags);
+	if (unlikely(file_priv && chan->file_priv != file_priv)) {
+		nouveau_channel_put_unlocked(&chan);
 		return ERR_PTR(-EINVAL);
 	}
 
-	spin_unlock_irqrestore(&dev_priv->channels.lock, flags);
-
 	mutex_lock(&chan->mutex);
 	return chan;
 }
 
 void
-nouveau_channel_put(struct nouveau_channel **pchan)
+nouveau_channel_put_unlocked(struct nouveau_channel **pchan)
 {
 	struct nouveau_channel *chan = *pchan;
 	struct drm_device *dev = chan->dev;
@@ -274,9 +280,6 @@ nouveau_channel_put(struct nouveau_channel **pchan)
 	unsigned long flags;
 	int ret;
 
-	/* unlock the channel */
-	mutex_unlock(&chan->mutex);
-
 	/* decrement the refcount, and we're done if there's still refs */
 	if (likely(!atomic_dec_and_test(&chan->refcount))) {
 		*pchan = NULL;
@@ -348,6 +351,13 @@ nouveau_channel_put(struct nouveau_channel **pchan)
 	kfree(chan);
 }
 
+void
+nouveau_channel_put(struct nouveau_channel **pchan)
+{
+	mutex_unlock(&(*pchan)->mutex);
+	nouveau_channel_put_unlocked(pchan);
+}
+
 /* cleans up all the fifos from file_priv */
 void
 nouveau_channel_cleanup(struct drm_device *dev, struct drm_file *file_priv)

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -803,7 +803,10 @@ extern int  nouveau_channel_alloc(struct drm_device *dev,
 				  struct drm_file *file_priv,
 				  uint32_t fb_ctxdma, uint32_t tt_ctxdma);
 extern struct nouveau_channel *
+nouveau_channel_get_unlocked(struct nouveau_channel *);
+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 **);
 
 /* nouveau_object.c */