linux-kernel - [PATCH] dmapool: remove redundant NULL check for dev in dma_pool

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Message-ID: <20140429025310.GA5913@devel>
Date:	Tue, 29 Apr 2014 11:53:10 +0900
From:	Daeseok Youn <daeseok.youn@...il.com>
To:	akpm@...ux-foundation.org
Cc:	daeseok.youn@...il.com, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] dmapool: remove redundant NULL check for dev in
 dma_pool_create()

"dev" cannot be NULL because it is already checked before
calling dma_pool_create().

Signed-off-by: Daeseok Youn <daeseok.youn@...il.com>
---
If dev can be NULL, it has NULL deferencing when kmalloc_node()
is called after enabling CONFIG_NUMA.

 mm/dmapool.c |   26 +++++++++-----------------
 1 files changed, 9 insertions(+), 17 deletions(-)

diff --git a/mm/dmapool.c b/mm/dmapool.c
index c69781e..38dfcdd 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -170,24 +170,16 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
 	retval->boundary = boundary;
 	retval->allocation = allocation;
 
-	if (dev) {
-		int ret;
+	INIT_LIST_HEAD(&retval->pools);
 
-		mutex_lock(&pools_lock);
-		if (list_empty(&dev->dma_pools))
-			ret = device_create_file(dev, &dev_attr_pools);
-		else
-			ret = 0;
-		/* note:  not currently insisting "name" be unique */
-		if (!ret)
-			list_add(&retval->pools, &dev->dma_pools);
-		else {
-			kfree(retval);
-			retval = NULL;
-		}
-		mutex_unlock(&pools_lock);
+	mutex_lock(&pools_lock);
+	if (list_empty(&dev->dma_pools) &&
+	    device_create_file(dev, &dev_attr_pools)) {
+		kfree(retval);
+		return NULL;
 	} else
-		INIT_LIST_HEAD(&retval->pools);
+		list_add(&retval->pools, &dev->dma_pools);
+	mutex_unlock(&pools_lock);
 
 	return retval;
 }
-- 
1.7.4.4

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