mtd: m25p80: fix allocation size

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=778d226a1462572b51d6777cdb1d611543410cb4
Commit:     778d226a1462572b51d6777cdb1d611543410cb4
Parent:     7caa4fd29068cccaa7be20914af6d23f261be3eb
Author:     Brian Norris <computersforpeace at gmail.com>
AuthorDate: Wed Jul 24 18:32:07 2013 -0700
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Wed Nov 6 23:33:04 2013 -0800

    mtd: m25p80: fix allocation size
    
    This patch fixes two memory errors:
    
    1. During a probe failure (in mtd_device_parse_register?) the command
       buffer would not be freed.
    
    2. The command buffer's size is determined based on the 'fast_read'
       boolean, but the assignment of fast_read is made after this
       allocation. Thus, the buffer may be allocated "too small".
    
    To fix the first, just switch to the devres version of kzalloc.
    
    To fix the second, increase MAX_CMD_SIZE unconditionally. It's not worth
    saving a byte to fiddle around with the conditions here.
    
    This problem was reported by Yuhang Wang a while back.
    
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
    Reported-by: Yuhang Wang <wangyuhang2014 at gmail.com>
    Reviewed-by: Sourav Poddar <sourav.poddar at ti.com>
    Cc: <stable at vger.kernel.org>
---
 drivers/mtd/devices/m25p80.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 8d6c87be..63a95ac 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -78,7 +78,7 @@
 
 /* Define max times to check status register before we give up. */
 #define	MAX_READY_WAIT_JIFFIES	(40 * HZ)	/* M25P16 specs 40s max chip erase */
-#define	MAX_CMD_SIZE		5
+#define	MAX_CMD_SIZE		6
 
 #define JEDEC_MFR(_jedec_id)	((_jedec_id) >> 16)
 
@@ -996,15 +996,13 @@ static int m25p_probe(struct spi_device *spi)
 		}
 	}
 
-	flash = kzalloc(sizeof *flash, GFP_KERNEL);
+	flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
 	if (!flash)
 		return -ENOMEM;
-	flash->command = kmalloc(MAX_CMD_SIZE + (flash->fast_read ? 1 : 0),
-					GFP_KERNEL);
-	if (!flash->command) {
-		kfree(flash);
+
+	flash->command = devm_kzalloc(&spi->dev, MAX_CMD_SIZE, GFP_KERNEL);
+	if (!flash->command)
 		return -ENOMEM;
-	}
 
 	flash->spi = spi;
 	mutex_init(&flash->lock);
@@ -1137,14 +1135,10 @@ static int m25p_probe(struct spi_device *spi)
 static int m25p_remove(struct spi_device *spi)
 {
 	struct m25p	*flash = spi_get_drvdata(spi);
-	int		status;
 
 	/* Clean up MTD stuff. */
-	status = mtd_device_unregister(&flash->mtd);
-	if (status == 0) {
-		kfree(flash->command);
-		kfree(flash);
-	}
+	mtd_device_unregister(&flash->mtd);
+
 	return 0;
 }