On 14/10/24 14:44, Avri Altman wrote: > 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://www.spinics.net/lists/linux-mmc/msg82199.html > > Suggested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> > Signed-off-by: Avri Altman <avri.altman@xxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > --- > drivers/mmc/core/block.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c > index 04f3165cf9ae..042b0147d47e 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 = {}; > @@ -1018,9 +1020,13 @@ 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); Could have memalloc_noio_restore() here: memalloc_noio_restore(noio_flag); but I feel maybe adding something like: u64 __aligned(8) tiny_io_buf; to either struct mmc_card or struct mmc_host is better? Ulf, any thoughts? > - if (!blocks) > + if (!blocks) { > + memalloc_noio_restore(noio_flag); > return -ENOMEM; > + } > > sg_init_one(&sg, blocks, resp_sz); > > @@ -1041,6 +1047,8 @@ static int mmc_sd_num_wr_blocks(struct mmc_card *card, u32 *written_blocks) > } > kfree(blocks); > > + memalloc_noio_restore(noio_flag); > + > if (cmd.error || data.error) > return -EIO; >
