Commit adc064cd authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Vinod Koul
Browse files

dmaengine: Convert ID allocation to an IDA 



dmaengine currently uses an IDR to allocate DMA IDs, but it only needs
to know whether IDs are in use or not; the ID to pointer functionality
of the IDR is unused.  That means it can use the more space-efficient IDA.

Signed-off-by: default avatarMatthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 0c744ea4

drivers/dma/dmaengine.c

+11 −10
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ 
#include <linux/mempool.h>



static DEFINE_MUTEX(dma_list_mutex);

static DEFINE_IDR(dma_idr);

static DEFINE_IDA(dma_ida);

static LIST_HEAD(dma_device_list);

static long dmaengine_ref_count;
@@ -162,7 +162,7 @@ static void chan_dev_release(struct device *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);

		ida_remove(&dma_ida, chan_dev->dev_id);

		mutex_unlock(&dma_list_mutex);

		kfree(chan_dev->idr_ref);

	}
@@ -898,14 +898,15 @@ static int get_dma_id(struct dma_device *device) 
{

	int rc;



	do {

		if (!ida_pre_get(&dma_ida, GFP_KERNEL))

			return -ENOMEM;

		mutex_lock(&dma_list_mutex);



	rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);

	if (rc >= 0)

		device->dev_id = rc;



		rc = ida_get_new(&dma_ida, &device->dev_id);

		mutex_unlock(&dma_list_mutex);

	return rc < 0 ? rc : 0;

	} while (rc == -EAGAIN);



	return rc;

}



/**
@@ -1035,7 +1036,7 @@ err_out: 
	/* if we never registered a channel just release the idr */

	if (atomic_read(idr_ref) == 0) {

		mutex_lock(&dma_list_mutex);

		idr_remove(&dma_idr, device->dev_id);

		ida_remove(&dma_ida, device->dev_id);

		mutex_unlock(&dma_list_mutex);

		kfree(idr_ref);

		return rc;

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