dma: Make the 'mask' parameter of __dma_request_channel const

The 'mask' parameter is not modified in __dma_request_channel and really
shouldn't be. Make this explicit by making the parameter const.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/dmaengine.c

@@ -174,7 +174,8 @@ static struct class dma_devclass = {
 #define dma_device_satisfies_mask(device, mask) \
 	__dma_device_satisfies_mask((device), &(mask))
 static int
-__dma_device_satisfies_mask(struct dma_device *device, dma_cap_mask_t *want)
+__dma_device_satisfies_mask(struct dma_device *device,
+			    const dma_cap_mask_t *want)
 {
 	dma_cap_mask_t has;
 
@@ -463,7 +464,8 @@ static void dma_channel_rebalance(void)
 		}
 }
 
-static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev,
+static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
+					  struct dma_device *dev,
 					  dma_filter_fn fn, void *fn_param)
 {
 	struct dma_chan *chan;
@@ -505,7 +507,8 @@ static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_devic
  * @fn: optional callback to disposition available channels
  * @fn_param: opaque parameter to pass to dma_filter_fn
  */
-struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param)
+struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
+				       dma_filter_fn fn, void *fn_param)
 {
 	struct dma_device *device, *_d;
 	struct dma_chan *chan = NULL;

include/linux/dmaengine.h

@@ -967,7 +967,8 @@ enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);
 #ifdef CONFIG_DMA_ENGINE
 enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
 void dma_issue_pending_all(void);
-struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param);
+struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
+					dma_filter_fn fn, void *fn_param);
 struct dma_chan *dma_request_slave_channel(struct device *dev, char *name);
 void dma_release_channel(struct dma_chan *chan);
 #else
@@ -978,7 +979,7 @@ static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descript
 static inline void dma_issue_pending_all(void)
 {
 }
-static inline struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask,
+static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
 					      dma_filter_fn fn, void *fn_param)
 {
 	return NULL;
@@ -1005,9 +1006,9 @@ struct dma_chan *net_dma_find_channel(void);
 	__dma_request_slave_channel_compat(&(mask), x, y, dev, name)
 
 static inline struct dma_chan
-*__dma_request_slave_channel_compat(dma_cap_mask_t *mask, dma_filter_fn fn,
-				  void *fn_param, struct device *dev,
-				  char *name)
+*__dma_request_slave_channel_compat(const dma_cap_mask_t *mask,
+				  dma_filter_fn fn, void *fn_param,
+				  struct device *dev, char *name)
 {
 	struct dma_chan *chan;