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-rw-r--r--drivers/dma/dmaengine.c27
-rw-r--r--include/linux/dmaengine.h4
2 files changed, 29 insertions, 2 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 93c4c9ac8997..dd43410c1019 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);
}
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index d6b6bff355f4..64dea2ab326c 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -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)