net_dma: call dmaengine_get only if NET_DMA enabled

Based upon a patch from Atsushi Nemoto <anemo@mba.ocn.ne.jp>

--------------------
The commit 649274d9 ("net_dma:
acquire/release dma channels on ifup/ifdown") added unconditional call
of dmaengine_get() to net_dma.  The API should be called only if
NET_DMA was enabled.
--------------------
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dan Williams <dan.j.williams@intel.com>

include/linux/dmaengine.h

@@ -282,6 +282,18 @@ static inline void dmaengine_put(void)
 }
 #endif
 
+#ifdef CONFIG_NET_DMA
+#define net_dmaengine_get()	dmaengine_get()
+#define net_dmaengine_put()	dmaengine_put()
+#else
+static inline void net_dmaengine_get(void)
+{
+}
+static inline void net_dmaengine_put(void)
+{
+}
+#endif
+
 dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
 	void *dest, void *src, size_t len);
 dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,

net/core/dev.c

@@ -1090,7 +1090,7 @@ int dev_open(struct net_device *dev)
 		/*
 		 *	Enable NET_DMA
 		 */
-		dmaengine_get();
+		net_dmaengine_get();
 
 		/*
 		 *	Initialize multicasting status
@@ -1172,7 +1172,7 @@ int dev_close(struct net_device *dev)
 	/*
 	 *	Shutdown NET_DMA
 	 */
-	dmaengine_put();
+	net_dmaengine_put();
 
 	return 0;
 }