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authorDan Williams <dan.j.williams@intel.com>2009-01-06 11:38:21 -0700
committerDan Williams <dan.j.williams@intel.com>2009-01-06 11:38:21 -0700
commit864498aaa9fef69ee166da023d12413a7776342d (patch)
tree023d6bfc15ba192c1a92caab3ff7525a84e409fc /drivers/dma
parent41d5e59c1299f27983977bcfe3b360600996051c (diff)
downloadop-kernel-dev-864498aaa9fef69ee166da023d12413a7776342d.zip
op-kernel-dev-864498aaa9fef69ee166da023d12413a7776342d.tar.gz
dmaengine: use idr for registering dma device numbers
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>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/dmaengine.c27
1 files changed, 25 insertions, 2 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 93c4c9a..dd43410 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -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);
}
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