From b0b42b16ff2b90f17bc1a4308366c9beba4b276e Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Wed, 3 Dec 2008 17:17:07 -0700
Subject: 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>

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 5317e08..6579965 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) {
-- 
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