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Commit 649274d9 authored by Dan Williams's avatar Dan Williams Committed by David S. Miller
Browse files

net_dma: acquire/release dma channels on ifup/ifdown 



The recent dmaengine rework removed the capability to remove dma device
driver modules while net_dma is active.  Rather than notify
dmaengine-clients that channels are trying to be removed, we now rely on
clients to notify dmaengine when they no longer have a need for
channels.  Teach net_dma to release channels by taking dmaengine
references at netdevice open and dropping references at netdevice close.

Acked-by: default avatarMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 47fd23fe

include/linux/dmaengine.h

+10 −0
Original line number Diff line number Diff line
@@ -270,8 +270,18 @@ struct dma_device { 


/* --- public DMA engine API --- */



#ifdef CONFIG_DMA_ENGINE

void dmaengine_get(void);

void dmaengine_put(void);

#else

static inline void dmaengine_get(void)

{

}

static inline void 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

+10 −3
Original line number Diff line number Diff line
@@ -1087,6 +1087,11 @@ int dev_open(struct net_device *dev) 
		 */

		dev->flags |= IFF_UP;



		/*

		 *	Enable NET_DMA

		 */

		dmaengine_get();



		/*

		 *	Initialize multicasting status

		 */
@@ -1164,6 +1169,11 @@ int dev_close(struct net_device *dev) 
	 */

	call_netdevice_notifiers(NETDEV_DOWN, dev);



	/*

	 *	Shutdown NET_DMA

	 */

	dmaengine_put();



	return 0;

}
@@ -5151,9 +5161,6 @@ static int __init net_dev_init(void) 
	hotcpu_notifier(dev_cpu_callback, 0);

	dst_init();

	dev_mcast_init();

	#ifdef CONFIG_NET_DMA

	dmaengine_get();

	#endif

	rc = 0;

out:

	return rc;