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dmaengine: add a release for dma class devices and dependent infrastructure

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Resolves:
WARNING: at drivers/base/core.c:122 device_release+0x4d/0x52()
Device 'dma0chan0' does not have a release() function, it is broken and must be fixed.

The dma_chan_dev object is introduced to gear-match sysfs kobject and
dmaengine channel lifetimes.  When a channel is removed access to the
sysfs entries return -ENODEV until the kobject can be released.

The bulk of the change is updates to existing code to handle the extra
layer of indirection between a dma_chan and its struct device.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams
2009-01-06 11:38:21 -07:00
parent 4fac7fa57c
commit 41d5e59c12
5 changed files with 157 additions and 75 deletions
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19
include/linux/dmaengine.h
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@ -113,7 +113,7 @@ struct dma_chan_percpu {
* @device: ptr to the dma device who supplies this channel, always !%NULL
* @cookie: last cookie value returned to client
* @chan_id: channel ID for sysfs
* @class_dev: class device for sysfs
* @dev: class device for sysfs
* @refcount: kref, used in "bigref" slow-mode
* @slow_ref: indicates that the DMA channel is free
* @rcu: the DMA channel's RCU head
@ -128,7 +128,7 @@ struct dma_chan {
/* sysfs */
int chan_id;
struct device dev;
struct dma_chan_dev *dev;
struct list_head device_node;
struct dma_chan_percpu *local;
@ -136,7 +136,20 @@ struct dma_chan {
int table_count;
};
#define to_dma_chan(p) container_of(p, struct dma_chan, dev)
/**
* struct dma_chan_dev - relate sysfs device node to backing channel device
* @chan - driver channel device
* @device - sysfs device
*/
struct dma_chan_dev {
struct dma_chan *chan;
struct device device;
};
static inline const char *dma_chan_name(struct dma_chan *chan)
{
return dev_name(&chan->dev->device);
}
void dma_chan_cleanup(struct kref *kref);