target/linux/generic/backport-5.15/423-v6.3-mtd-spinand-macronix-use-scratch-buffer-for-DMA-oper.patch

   1 From ebed787a0becb9354f0a23620a5130cccd6c730c Mon Sep 17 00:00:00 2001
   2 From: Daniel Golle <daniel@makrotopia.org>
   3 Date: Thu, 19 Jan 2023 03:45:43 +0000
   4 Subject: [PATCH] mtd: spinand: macronix: use scratch buffer for DMA operation
   5
   6 The mx35lf1ge4ab_get_eccsr() function uses an SPI DMA operation to
   7 read the eccsr, hence the buffer should not be on stack. Since commit
   8 380583227c0c7f ("spi: spi-mem: Add extra sanity checks on the op param")
   9 the kernel emmits a warning and blocks such operations.
  10
  11 Use the scratch buffer to get eccsr instead of trying to directly read
  12 into a stack-allocated variable.
  13
  14 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  15 Reviewed-by: Dhruva Gole <d-gole@ti.com>
  16 Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
  17 Link: https://lore.kernel.org/linux-mtd/Y8i85zM0u4XdM46z@makrotopia.org
  18 ---
  19  drivers/mtd/nand/spi/macronix.c | 3 ++-
  20  1 file changed, 2 insertions(+), 1 deletion(-)
  21
  22 --- a/drivers/mtd/nand/spi/macronix.c
  23 +++ b/drivers/mtd/nand/spi/macronix.c
  24 @@ -83,9 +83,10 @@ static int mx35lf1ge4ab_ecc_get_status(s
  25                  * in order to avoid forcing the wear-leveling layer to move
  26                  * data around if it's not necessary.
  27                  */
  28 -               if (mx35lf1ge4ab_get_eccsr(spinand, &eccsr))
  29 +               if (mx35lf1ge4ab_get_eccsr(spinand, spinand->scratchbuf))
  30                         return nanddev_get_ecc_conf(nand)->strength;
  31
  32 +               eccsr = *spinand->scratchbuf;
  33                 if (WARN_ON(eccsr > nanddev_get_ecc_conf(nand)->strength ||
  34                             !eccsr))
  35                         return nanddev_get_ecc_conf(nand)->strength;