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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: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dan Williams 2009-01-11 00:20:39 -08:00 committed by David S. Miller
parent 47fd23fe8e
commit 649274d993
2 changed files with 20 additions and 3 deletions
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10
include/linux/dmaengine.h
View File

@ -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,

13
net/core/dev.c
View File

@ -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;