Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

dmaengine: use idr for registering dma device numbers

Browse source 
This brings some predictability to dma device numbers, i.e. an rmmod/insmod
cycle may now result in /sys/class/dma/dma0chan0 being restored rather than
/sys/class/dma/dma1chan0 appearing.

Cc: Maciej Sosnowski <maciej.sosnowski@intel.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 41d5e59c12
commit 864498aaa9
2 changed files with 29 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
drivers/dma/dmaengine.c
View file

@ -57,10 +57,12 @@
#include <linux/mutex.h>
#include <linux/jiffies.h>
#include <linux/rculist.h>
#include <linux/idr.h>
static DEFINE_MUTEX(dma_list_mutex);
static LIST_HEAD(dma_device_list);
static long dmaengine_ref_count;
static struct idr dma_idr;
/* --- sysfs implementation --- */
@ -147,6 +149,12 @@ static void chan_dev_release(struct device *dev)
struct dma_chan_dev *chan_dev;
chan_dev = container_of(dev, typeof(*chan_dev), device);
if (atomic_dec_and_test(chan_dev->idr_ref)) {
mutex_lock(&dma_list_mutex);
idr_remove(&dma_idr, chan_dev->dev_id);
mutex_unlock(&dma_list_mutex);
kfree(chan_dev->idr_ref);
}
kfree(chan_dev);
}
@ -611,9 +619,9 @@ EXPORT_SYMBOL(dmaengine_put);
*/
int dma_async_device_register(struct dma_device *device)
{
static int id;
int chancnt = 0, rc;
struct dma_chan* chan;
atomic_t *idr_ref;
if (!device)
return -ENODEV;
@ -640,9 +648,20 @@ int dma_async_device_register(struct dma_device *device)
BUG_ON(!device->device_issue_pending);
BUG_ON(!device->dev);
idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
if (!idr_ref)
return -ENOMEM;
atomic_set(idr_ref, 0);
idr_retry:
if (!idr_pre_get(&dma_idr, GFP_KERNEL))
return -ENOMEM;
mutex_lock(&dma_list_mutex);
device->dev_id = id++;
rc = idr_get_new(&dma_idr, NULL, &device->dev_id);
mutex_unlock(&dma_list_mutex);
if (rc == -EAGAIN)
goto idr_retry;
else if (rc != 0)
return rc;
/* represent channels in sysfs. Probably want devs too */
list_for_each_entry(chan, &device->channels, device_node) {
@ -659,6 +678,9 @@ int dma_async_device_register(struct dma_device *device)
chan->dev->device.class = &dma_devclass;
chan->dev->device.parent = device->dev;
chan->dev->chan = chan;
chan->dev->idr_ref = idr_ref;
chan->dev->dev_id = device->dev_id;
atomic_inc(idr_ref);
dev_set_name(&chan->dev->device, "dma%dchan%d",
device->dev_id, chan->chan_id);
@ -971,6 +993,7 @@ EXPORT_SYMBOL_GPL(dma_run_dependencies);
static int __init dma_bus_init(void)
{
idr_init(&dma_idr);
mutex_init(&dma_list_mutex);
return class_register(&dma_devclass);
}

4
include/linux/dmaengine.h
View file

@ -140,10 +140,14 @@ struct dma_chan {
* struct dma_chan_dev - relate sysfs device node to backing channel device
* @chan - driver channel device
* @device - sysfs device
* @dev_id - parent dma_device dev_id
* @idr_ref - reference count to gate release of dma_device dev_id
*/
struct dma_chan_dev {
struct dma_chan *chan;
struct device device;
int dev_id;
atomic_t *idr_ref;
};
static inline const char *dma_chan_name(struct dma_chan *chan)