linux-kernel - [PATCH 3.2 027/152] mtd: pmcmsp-flash: Allocating too much in init_msp

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Message-ID: <lsq.1479082447.467580417@decadent.org.uk>
Date:   Mon, 14 Nov 2016 00:14:07 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Brian Norris" <computersforpeace@...il.com>,
        "Dan Carpenter" <dan.carpenter@...cle.com>
Subject: [PATCH 3.2 027/152] mtd: pmcmsp-flash: Allocating too much in
 init_msp_flash()

3.2.84-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Dan Carpenter <dan.carpenter@...cle.com>

commit 79ad07d45743721010e766e65dc004ad249bd429 upstream.

There is a cut and paste issue here.  The bug is that we are allocating
more memory than necessary for msp_maps.  We should be allocating enough
space for a map_info struct (144 bytes) but we instead allocate enough
for an mtd_info struct (1840 bytes).  It's a small waste.

The other part of this is not harmful but when we allocated msp_flash
then we allocated enough space fro a map_info pointer instead of an
mtd_info pointer.  But since pointers are the same size it works out
fine.

Anyway, I decided to clean up all three allocations a bit to make them
a bit more consistent and clear.

Fixes: 68aa0fa87f6d ('[MTD] PMC MSP71xx flash/rootfs mappings')
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Brian Norris <computersforpeace@...il.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/mtd/maps/pmcmsp-flash.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/mtd/maps/pmcmsp-flash.c
+++ b/drivers/mtd/maps/pmcmsp-flash.c
@@ -75,15 +75,15 @@ static int __init init_msp_flash(void)
 
 	printk(KERN_NOTICE "Found %d PMC flash devices\n", fcnt);
 
-	msp_flash = kmalloc(fcnt * sizeof(struct map_info *), GFP_KERNEL);
+	msp_flash = kcalloc(fcnt, sizeof(*msp_flash), GFP_KERNEL);
 	if (!msp_flash)
 		return -ENOMEM;
 
-	msp_parts = kmalloc(fcnt * sizeof(struct mtd_partition *), GFP_KERNEL);
+	msp_parts = kcalloc(fcnt, sizeof(*msp_parts), GFP_KERNEL);
 	if (!msp_parts)
 		goto free_msp_flash;
 
-	msp_maps = kcalloc(fcnt, sizeof(struct mtd_info), GFP_KERNEL);
+	msp_maps = kcalloc(fcnt, sizeof(*msp_maps), GFP_KERNEL);
 	if (!msp_maps)
 		goto free_msp_parts;