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: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 6b535262ac5d76972bb525b49f3cf160fcf54aa0..24e0221fd66d1ff58eead62ee9f4a865eb87da03 100644 (file)
--- 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 @@ 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;