linux-kernel - [PATCH] mtd: spinand: macronix: use scratch buffer for DMA operation

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Message-ID: <Y8i85zM0u4XdM46z@makrotopia.org>
Date:   Thu, 19 Jan 2023 03:45:43 +0000
From:   Daniel Golle <daniel@...rotopia.org>
To:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>
Cc:     Mason Yang <masonccyang@...c.com.tw>,
        Jianhui Zhao <zhaojh329@...il.com>
Subject: [PATCH] mtd: spinand: macronix: use scratch buffer for DMA operation

The mx35lf1ge4ab_get_eccsr() function uses an SPI DMA operation to
read the eccsr, hence the buffer should not be on stack. Since commit
380583227c0c7f ("spi: spi-mem: Add extra sanity checks on the op param")
the kernel emmits a warning and blocks such operations.

Use the scratch buffer to get eccsr instead of trying to directly read
into a stack-allocated variable.

Signed-off-by: Daniel Golle <daniel@...rotopia.org>
---
 drivers/mtd/nand/spi/macronix.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/spi/macronix.c b/drivers/mtd/nand/spi/macronix.c
index dce835132a1e2..722a9738ba370 100644
--- a/drivers/mtd/nand/spi/macronix.c
+++ b/drivers/mtd/nand/spi/macronix.c
@@ -83,9 +83,10 @@ static int mx35lf1ge4ab_ecc_get_status(struct spinand_device *spinand,
 		 * in order to avoid forcing the wear-leveling layer to move
 		 * data around if it's not necessary.
 		 */
-		if (mx35lf1ge4ab_get_eccsr(spinand, &eccsr))
+		if (mx35lf1ge4ab_get_eccsr(spinand, spinand->scratchbuf))
 			return nanddev_get_ecc_conf(nand)->strength;
 
+		eccsr = *spinand->scratchbuf;
 		if (WARN_ON(eccsr > nanddev_get_ecc_conf(nand)->strength ||
 			    !eccsr))
 			return nanddev_get_ecc_conf(nand)->strength;
-- 
2.39.1