mtd: spi-nor: Unprepare legacy controllers upon RWW wait interruption

All the parallel locking helpers (spi_nor_prep_and_lock(),
spi_nor_prep_and_lock_pe() and spi_nor_prep_and_lock_rd()) call
spi_nor_prep() then wait with a killable sleep. If the sleep gets
killed, we leave the controller in its prepared state.

Call ->unprepare() in these cases.

Fixes: 74df43b3f626 ("mtd: spi-nor: Enhance locking to support reads while writes")
Cc: stable@vger.kernel.org
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Michael Walle <mwalle@kernel.org>
Acked-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Michael Walle <mwalle@kernel.org>

drivers/mtd/spi-nor/core.c

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 69b7719..fca0d65 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1348,6 +1348,9 @@ int spi_nor_prep_and_lock(struct spi_nor *nor)
 		ret = wait_event_killable(nor->rww.wait,
 					  spi_nor_rww_start_exclusive(nor));
 
+	if (ret)
+		spi_nor_unprep(nor);
+
 	return ret;
 }
 
@@ -1419,6 +1422,9 @@ static int spi_nor_prep_and_lock_pe(struct spi_nor *nor, loff_t start, size_t le
 		ret = wait_event_killable(nor->rww.wait,
 					  spi_nor_rww_start_pe(nor, start, len));
 
+	if (ret)
+		spi_nor_unprep(nor);
+
 	return ret;
 }
 
@@ -1492,6 +1498,9 @@ static int spi_nor_prep_and_lock_rd(struct spi_nor *nor, loff_t start, size_t le
 		ret = wait_event_killable(nor->rww.wait,
 					  spi_nor_rww_start_rd(nor, start, len));
 
+	if (ret)
+		spi_nor_unprep(nor);
+
 	return ret;
 }