[PATCH v2] mtd: spi-nor: scope the exclusive RWW lock

[Runyu Xiao]

spi_nor_rww_start_exclusive() is used as the wait_event_killable()
condition for RWW access. When RWW is busy, it can return false while
still holding nor->lock, which blocks spi_nor_rww_end_exclusive() from
clearing the RWW state.

Use guard(mutex) here so nor->lock is released before the condition
returns, while the state flags still hand off ownership to the caller.
This keeps the mutex scope aligned with the other RWW start helpers.

Fixes: 03e7bb864d9a ("mtd: spi-nor: use scope-based mutex cleanup helpers")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Runyu Xiao <runyu.xiao@xxxxxxxxxx>
---
Changes in v2:
- Replace the analysis-style explanation with a short maintainer-facing
  description of the busy-path lock hold.
- Keep the fix focused on using guard(mutex) so the mutex is released on
  both paths.

drivers/mtd/spi-nor/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index ccf4396cdcd0..8bc117b46e02 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1310,7 +1310,7 @@ static bool spi_nor_rww_start_exclusive(struct spi_nor *nor)
 {
 	struct spi_nor_rww *rww = &nor->rww;
 
-	mutex_lock(&nor->lock);
+	guard(mutex)(&nor->lock);
 
 	if (rww->ongoing_io || rww->ongoing_rd || rww->ongoing_pe)
 		return false;
-- 
2.34.1