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Commit 06a7643c authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by David Woodhouse
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[MTD] [NAND] fix race in nand_base.c 



When we mark block bad we have to get chip because this involves
writing to the page's OOB. We hit this bug in UBI - we observed
random obscure crashes when it marks block bad from the background
thread and there is some parallel task which utilizes flash.

This patch also adds a TODO note about BBT table protection which
it seems does not exist.

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 9d7b4b55

drivers/mtd/nand/nand_base.c

+4 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
 *	if we have HW ecc support.

 *	The AG-AND chips have nice features for speed improvement,

 *	which are not supported yet. Read / program 4 pages in one go.

 *	BBT table is not serialized, has to be fixed

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as
@@ -360,6 +361,7 @@ static int nand_default_block_markbad(struct mtd_info *mtd, loff_t ofs) 
		/* We write two bytes, so we dont have to mess with 16 bit

		 * access

		 */

		nand_get_device(chip, mtd, FL_WRITING);

		ofs += mtd->oobsize;

		chip->ops.len = chip->ops.ooblen = 2;

		chip->ops.datbuf = NULL;
@@ -367,9 +369,11 @@ static int nand_default_block_markbad(struct mtd_info *mtd, loff_t ofs) 
		chip->ops.ooboffs = chip->badblockpos & ~0x01;



		ret = nand_do_write_oob(mtd, ofs, &chip->ops);

		nand_release_device(mtd);

	}

	if (!ret)

		mtd->ecc_stats.badblocks++;



	return ret;

}