linux-kernel - [ 60/78] regmap: prevent division by zero in rbtree

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Message-Id: <20120411231028.538774815@linuxfoundation.org>
Date:	Wed, 11 Apr 2012 16:11:18 -0700
From:	Greg KH <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk, Stephen Warren <swarren@...dia.com>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [ 60/78] regmap: prevent division by zero in rbtree_show

3.3-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stephen Warren <swarren@...dia.com>

commit c04c1b9ee8f30c7a3a25e20e406247003f634ebe upstream.

If there are no nodes in the cache, nodes will be 0, so calculating
"registers / nodes" will cause division by zero.

Signed-off-by: Stephen Warren <swarren@...dia.com>
Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/base/regmap/regcache-rbtree.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/base/regmap/regcache-rbtree.c
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -137,6 +137,7 @@ static int rbtree_show(struct seq_file *
 	unsigned int base, top;
 	int nodes = 0;
 	int registers = 0;
+	int average;
 
 	mutex_lock(&map->lock);
 
@@ -151,8 +152,13 @@ static int rbtree_show(struct seq_file *
 		registers += top - base + 1;
 	}
 
+	if (nodes)
+		average = registers / nodes;
+	else
+		average = 0;
+
 	seq_printf(s, "%d nodes, %d registers, average %d registers\n",
-		   nodes, registers, registers / nodes);
+		   nodes, registers, average);
 
 	mutex_unlock(&map->lock);
 


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