dmaengine: protect 'id' from concurrent registrations

There is a possibility to have two devices registered with the same id.

Cc: <stable@kernel.org>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 5317e08221ec..657996517374 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -388,7 +388,10 @@ int dma_async_device_register(struct dma_device *device)
 
         init_completion(&device->done);
         kref_init(&device->refcount);
+
+        mutex_lock(&dma_list_mutex);
         device->dev_id = id++;
+        mutex_unlock(&dma_list_mutex);
 
         /* represent channels in sysfs. Probably want devs too */
         list_for_each_entry(chan, &device->channels, device_node) {