Patch "mtd: nand: Fix nand_do_read_oob() return value" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

mtd: nand: Fix nand_do_read_oob() return value

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mtd-nand-fix-nand_do_read_oob-return-value.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Miquel Raynal <[email protected]>
Date: Fri, 12 Jan 2018 10:13:36 +0100
Subject: mtd: nand: Fix nand_do_read_oob() return value

From: Miquel Raynal <[email protected]>

commit 87e89ce8d0d14f573c068c61bec2117751fb5103 upstream.

Starting from commit 041e4575f034 ("mtd: nand: handle ECC errors in OOB"), nand_do_read_oob() (from the NAND core) did return 0 or a negative error, and the MTD layer expected it.

However, the trend for the NAND layer is now to return an error or a positive number of bitflips. Deciding which status to return to the user belongs to the MTD layer.

Commit e47f68587b82 ("mtd: check for max_bitflips in mtd_read_oob()") brought this logic to the mtd_read_oob() function while the return value coming from nand_do_read_oob() (called by the ->_read_oob() hook) was left unchanged.

---
 drivers/mtd/nand/nand_base.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

@@ -2201,6 +2201,7 @@ EXPORT_SYMBOL(nand_write_oob_syndrome);
 static int nand_do_read_oob(struct mtd_info *mtd, loff_t from,
 			    struct mtd_oob_ops *ops)
 {
+	unsigned int max_bitflips = 0;
 	int page, realpage, chipnr;
 	struct nand_chip *chip = mtd_to_nand(mtd);
 	struct mtd_ecc_stats stats;

@@ -2258,6 +2259,8 @@ static int nand_do_read_oob(struct mtd_i
 				nand_wait_ready(mtd);
 		}
 
+		max_bitflips = max_t(unsigned int, max_bitflips, ret);
+
 		readlen -= len;
 		if (!readlen)
 			break;

@@ -2283,7 +2286,7 @@ static int nand_do_read_oob(struct mtd_i
 	if (mtd->ecc_stats.failed - stats.failed)
 		return -EBADMSG;
 
-	return  mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
+	return max_bitflips;
 }
 
 /**

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/mtd-nand-sunxi-fix-ecc-strength-choice.patch queue-4.14/mtd-nand-fix-nand_do_read_oob-return-value.patch