dmaengine: use idr for registering dma device numbers (864498aa) · Commits · 戴 / test

drivers/dma/dmaengine.c

+25 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}

include/linux/dmaengine.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -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)

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