From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
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: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
---
drivers/dma/dmaengine.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 6b53526..24e0221 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -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;
- mutex_lock(&dma_list_mutex);
-
- rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);
- if (rc >= 0)
- device->dev_id = rc;
+ do {
+ if (!ida_pre_get(&dma_ida, GFP_KERNEL))
+ return -ENOMEM;
+ mutex_lock(&dma_list_mutex);
+ rc = ida_get_new(&dma_ida, &device->dev_id);
+ mutex_unlock(&dma_list_mutex);
+ } while (rc == -EAGAIN);
- mutex_unlock(&dma_list_mutex);
- return rc < 0 ? rc : 0;
+ return rc;
}
/**
@@ -1035,7 +1036,7 @@ int dma_async_device_register(struct dma_device *device)
/* 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;
--
2.10.2
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