[PATCH 5.10 229/491] mtd: rawnand: serialize lock/unlock against other NAND operations

Greg Kroah-Hartman
2026-04-13T16:52:30Z

From: Kamal Dasu <kamal.dasu@broadcom.com>

[ Upstream commit bab2bc6e850a697a23b9e5f0e21bb8c187615e95 ]

nand_lock() and nand_unlock() call into chip->ops.lock_area/unlock_area
without holding the NAND device lock. On controllers that implement
SET_FEATURES via multiple low-level PIO commands, these can race with
concurrent UBI/UBIFS background erase/write operations that hold the
device lock, resulting in cmd_pending conflicts on the NAND controller.

Add nand_get_device()/nand_release_device() around the lock/unlock
operations to serialize them against all other NAND controller access.

Fixes: 92270086b7e5 ("mtd: rawnand: Add support for manufacturer specific lock/unlock operation")
Signed-off-by: Kamal Dasu <kamal.dasu@broadcom.com>
Reviewed-by: William Zhang <william.zhang@broadcom.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mtd/nand/raw/nand_base.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 308fcbe394a5e..b40dc3ac8615a 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -4383,11 +4383,16 @@ static void nand_shutdown(struct mtd_info *mtd)
static int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
struct nand_chip *chip = mtd_to_nand(mtd);
+ int ret;

if (!chip->ops.lock_area)
return -ENOTSUPP;

- return chip->ops.lock_area(chip, ofs, len);
+ nand_get_device(chip);
+ ret = chip->ops.lock_area(chip, ofs, len);
+ nand_release_device(chip);
+
+ return ret;
}

/**
@@ -4399,11 +4404,16 @@ static int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
static int nand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
struct nand_chip *chip = mtd_to_nand(mtd);
+ int ret;

if (!chip->ops.unlock_area)
return -ENOTSUPP;

- return chip->ops.unlock_area(chip, ofs, len);
+ nand_get_device(chip);
+ ret = chip->ops.unlock_area(chip, ofs, len);
+ nand_release_device(chip);
+
+ return ret;
}

/* Set default functions */
--
2.51.0