[PATCH v3] mmc: core: Use GFP_NOIO in ACMD22

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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@xxxxxxxxx/

Suggested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Reviewed-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Fixes: 051913dada04 ("mmc_block: do not DMA to stack")
Signed-off-by: Avri Altman <avri.altman@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx

---
Changes since v2:
 - Fix checkpatch warnings (Adrian)

Changes since v1:
 - Move memalloc_noio_restore around (Adrian)
---
 drivers/mmc/core/block.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 04f3165cf9ae..a813fd7f39cc 100644
--- 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;
 
-- 
2.25.1





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