Merge tag 'dmaengine-fix-5.6-rc1' of git://git.infradead.org/users/vkoul/slave-dma

Pull dmaengine fixes from Vinod Koul:
 "Fixes for:

   - Documentation build error fix

   - Fix dma_request_chan() error return

   - Remove unneeded conversion in idxd driver

   - Fix pointer check for dma_async_device_channel_register()

   - Fix slave-channel symlink cleanup"

* tag 'dmaengine-fix-5.6-rc1' of git://git.infradead.org/users/vkoul/slave-dma:
  dmaengine: Cleanups for the slave <-> channel symlink support
  dmaengine: fix null ptr check for __dma_async_device_channel_register()
  dmaengine: idxd: fix boolconv.cocci warnings
  dmaengine: Fix return value for dma_request_chan() in case of failure
  dmaengine: doc: Properly indent metadata title

Author: torvalds

Documentation/driver-api/dmaengine/client.rst

@@ -151,8 +151,8 @@ The details of these operations are:
      Note that callbacks will always be invoked from the DMA
      engines tasklet, never from interrupt context.
 
-  Optional: per descriptor metadata
-  ---------------------------------
+Optional: per descriptor metadata
+---------------------------------
   DMAengine provides two ways for metadata support.
 
   DESC_METADATA_CLIENT

drivers/dma/dmaengine.c

@@ -756,22 +756,21 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name)
 	}
 	mutex_unlock(&dma_list_mutex);
 
-	if (!IS_ERR_OR_NULL(chan))
-		goto found;
-
-	return ERR_PTR(-EPROBE_DEFER);
+	if (IS_ERR_OR_NULL(chan))
+		return chan ? chan : ERR_PTR(-EPROBE_DEFER);
 
 found:
-	chan->slave = dev;
 	chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
 	if (!chan->name)
-		return ERR_PTR(-ENOMEM);
+		return chan;
+	chan->slave = dev;
 
 	if (sysfs_create_link(&chan->dev->device.kobj, &dev->kobj,
 			      DMA_SLAVE_NAME))
-		dev_err(dev, "Cannot create DMA %s symlink\n", DMA_SLAVE_NAME);
+		dev_warn(dev, "Cannot create DMA %s symlink\n", DMA_SLAVE_NAME);
 	if (sysfs_create_link(&dev->kobj, &chan->dev->device.kobj, chan->name))
-		dev_err(dev, "Cannot create DMA %s symlink\n", chan->name);
+		dev_warn(dev, "Cannot create DMA %s symlink\n", chan->name);
+
 	return chan;
 }
 EXPORT_SYMBOL_GPL(dma_request_chan);
@@ -830,13 +829,14 @@ void dma_release_channel(struct dma_chan *chan)
 	/* drop PRIVATE cap enabled by __dma_request_channel() */
 	if (--chan->device->privatecnt == 0)
 		dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
+
 	if (chan->slave) {
+		sysfs_remove_link(&chan->dev->device.kobj, DMA_SLAVE_NAME);
 		sysfs_remove_link(&chan->slave->kobj, chan->name);
 		kfree(chan->name);
 		chan->name = NULL;
 		chan->slave = NULL;
 	}
-	sysfs_remove_link(&chan->dev->device.kobj, DMA_SLAVE_NAME);
 	mutex_unlock(&dma_list_mutex);
 }
 EXPORT_SYMBOL_GPL(dma_release_channel);
@@ -962,6 +962,9 @@ static int __dma_async_device_channel_register(struct dma_device *device,
 
 	tchan = list_first_entry_or_null(&device->channels,
 					 struct dma_chan, device_node);
+	if (!tchan)
+		return -ENODEV;
+
 	if (tchan->dev) {
 		idr_ref = tchan->dev->idr_ref;
 	} else {

drivers/dma/idxd/sysfs.c

@@ -66,7 +66,7 @@ static inline bool is_idxd_wq_dmaengine(struct idxd_wq *wq)
 
 static inline bool is_idxd_wq_cdev(struct idxd_wq *wq)
 {
-	return wq->type == IDXD_WQT_USER ? true : false;
+	return wq->type == IDXD_WQT_USER;
 }
 
 static int idxd_config_bus_match(struct device *dev,