mmc: core: Use GFP_NOIO in ACMD22

While reviewing the SDUC series, Adrian made a comment concerning the
memory allocation code in mmc_sd_num_wr_blocks() - see [1].
Prevent memory allocations from triggering I/O operations while ACMD22
is in progress.

[1] https://lore.kernel.org/linux-mmc/3016fd71-885b-4ef9-97ed-46b4b0cb0e35@intel.com/

Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 051913dada04 ("mmc_block: do not DMA to stack")
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Cc: stable@vger.kernel.org
Message-ID: <20241021153227.493970-1-avri.altman@wdc.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 04f3165cf9aeddb66f274dad0530430e4944caf2..a813fd7f39cc0b02bf6853bffc442fe82408291d 100644 (file)
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -995,6 +995,8 @@ static int mmc_sd_num_wr_blocks(struct mmc_card *card, u32 *written_blocks)
        u32 result;
        __be32 *blocks;
        u8 resp_sz = mmc_card_ult_capacity(card) ? 8 : 4;
+       unsigned int noio_flag;
+
        struct mmc_request mrq = {};
        struct mmc_command cmd = {};
        struct mmc_data data = {};
@@ -1018,7 +1020,9 @@ static int mmc_sd_num_wr_blocks(struct mmc_card *card, u32 *written_blocks)
        mrq.cmd = &cmd;
        mrq.data = &data;
 
+       noio_flag = memalloc_noio_save();
        blocks = kmalloc(resp_sz, GFP_KERNEL);
+       memalloc_noio_restore(noio_flag);
        if (!blocks)
                return -ENOMEM;