linux-kernel - Re: [Patch] Improve error handling in allocation of bounce buffers in mmc_init

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Message-ID: <547EAC4E.1090902@mentor.com>
Date:	Wed, 3 Dec 2014 11:53:10 +0530
From:	Bhuvanesh <bhuvanesh_surachari@...tor.com>
To:	Ulf Hansson <ulf.hansson@...aro.org>
CC:	Chris Ball <chris@...ntf.net>, Mike Snitzer <snitzer@...hat.com>,
	Jens Axboe <axboe@...com>,
	Russell King <rmk+kernel@....linux.org.uk>,
	Joe Perches <joe@...ches.com>, <harish_kandiga@...tor.com>,
	linux-mmc <linux-mmc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [Patch] Improve error handling in allocation of bounce buffers
 in mmc_init_queue

Hi,
  
  Thanks for guiding. I read through Documentation/SubmittingPatches.
Fixed the warnings given by checkpatch. Kindly review the updated patch.

>From 7ea020e32e1fbe4d05d104e31815d908af92f2a5 Mon Sep 17 00:00:00 2001
From: Bhuvanesh Surachari <bhuvanesh_surachari@...tor.com>
Date: Mon, 1 Dec 2014 02:23:02 -0500
Subject: [PATCH] mmc: queue:Improve error handling during allocation of
 bounce buffers.

Allocation of previous bounce buffer in mmc_init_queue when the current
bounce buffer allocation fails was leading to a crash later in
__blk_segment_map_sg. Error handling is improved by allocating previous
bounce buffer only if the current bounce buffer allocation succeeds.

Signed-off-by: Bhuvanesh Surachari <bhuvanesh_surachari@...tor.com>
Signed-off-by: Harish Jenny K N <harish_kandiga@...tor.com>
---
 drivers/mmc/card/queue.c |   16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index cfa6110..236d194 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -232,13 +232,15 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
 			if (!mqrq_cur->bounce_buf) {
 				pr_warn("%s: unable to allocate bounce cur buffer\n",
 					mmc_card_name(card));
-			}
-			mqrq_prev->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
-			if (!mqrq_prev->bounce_buf) {
-				pr_warn("%s: unable to allocate bounce prev buffer\n",
-					mmc_card_name(card));
-				kfree(mqrq_cur->bounce_buf);
-				mqrq_cur->bounce_buf = NULL;
+			} else {
+				mqrq_prev->bounce_buf =
+						kmalloc(bouncesz, GFP_KERNEL);
+				if (!mqrq_prev->bounce_buf) {
+					pr_warn("%s: unable to allocate bounce prev buffer\n",
+						mmc_card_name(card));
+					kfree(mqrq_cur->bounce_buf);
+					mqrq_cur->bounce_buf = NULL;
+				}
 			}
 		}
 
-- 
1.7.9.5



Thank you,
Regards,
Bhuvanesh

On 12/02/2014 05:01 PM, Ulf Hansson wrote:
> On 1 December 2014 at 12:56, Bhuvanesh <bhuvanesh_surachari@...tor.com> wrote:
>> Hi,
>>
>>   Please find the patch inline.
> 
> Apparently you didn't read /Documentation/SubmittingPatches.
> 
> If you want me to review, please follow that guide. For example, I
> expect you to run checkpatch.
> 
> Kind regards
> Uffe
> 
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