linux-kernel - [PATCH 4/6] mtd: nand_bbt: unify/fix error handling in nand_scan

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Message-ID: <87F60714EC601C4C83DFF1D2E3D390A02728257A@NTXXIAMBX02.xacn.micron.com>
Date:	Thu, 16 Apr 2015 02:13:28 +0000
From:	Peter Pan 潘栋 (peterpandong) 
	<peterpandong@...ron.com>
To:	"dwmw2@...radead.org" <dwmw2@...radead.org>,
	Brian Norris <computersforpeace@...il.com>,
	"ezequiel.garcia@...e-electrons.com" 
	<ezequiel.garcia@...e-electrons.com>,
	"zajec5@...il.com" <zajec5@...il.com>
CC:	"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH 4/6] mtd: nand_bbt: unify/fix error handling in
 nand_scan_bbt()

Don't leak this->bbt, and return early if check_create() fails. It helps
to have a single error path to avoid these problems.

Signed-off-by: Brian Norris <computersforpeace@...il.com>
Signed-off-by: Peter Pan <peterpandong@...ron.com>
---
 drivers/mtd/nand/nand_bbt.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index 53e1758..516db2c 100644
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -1077,7 +1077,7 @@ static void verify_bbt_descr(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 static int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 {
 	struct nand_chip *this = mtd->priv;
-	int len, res = 0;
+	int len, res;
 	uint8_t *buf;
 	struct nand_bbt_descr *td = this->bbt_td;
 	struct nand_bbt_descr *md = this->bbt_md;
@@ -1098,10 +1098,9 @@ static int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 	if (!td) {
 		if ((res = nand_memory_bbt(mtd, bd))) {
 			pr_err("nand_bbt: can't scan flash and build the RAM-based BBT\n");
-			kfree(this->bbt);
-			this->bbt = NULL;
+			goto err;
 		}
-		return res;
+		return 0;
 	}
 	verify_bbt_descr(mtd, td);
 	verify_bbt_descr(mtd, md);
@@ -1111,9 +1110,8 @@ static int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 	len += (len >> this->page_shift) * mtd->oobsize;
 	buf = vmalloc(len);
 	if (!buf) {
-		kfree(this->bbt);
-		this->bbt = NULL;
-		return -ENOMEM;
+		res = -ENOMEM;
+		goto err;
 	}
 
 	/* Is the bbt at a given page? */
@@ -1125,6 +1123,8 @@ static int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 	}
 
 	res = check_create(mtd, buf, bd);
+	if (res)
+		goto err;
 
 	/* Prevent the bbt regions from erasing / writing */
 	mark_bbt_region(mtd, td);
@@ -1132,6 +1132,11 @@ static int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 		mark_bbt_region(mtd, md);
 
 	vfree(buf);
+	return 0;
+
+err:
+	kfree(this->bbt);
+	this->bbt = NULL;
 	return res;
 }
 
-- 
1.9.1