On 7/10/22 18:42, Christian Löhle wrote:
> Before switching back to the right partition in mmc_blk_reset
> there used to be a check if hw_reset was even supported.
> This return value was removed, so there is no reason to check.
>
> Fixes: fefdd3c91e0a ("mmc: core: Drop superfluous validations in mmc_hw|sw_reset()")
> Cc: stable@xxxxxxxxxxxxxxx
>
> Signed-off-by: Christian Loehle <cloehle@xxxxxxxxxxxxxx>
> ---
> -v2: Do not attempt to switch partitions if reset failed
>
> drivers/mmc/core/block.c | 28 +++++++++++++---------------
> 1 file changed, 13 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index ce89611a136e..8db72cba2bbe 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -991,29 +991,27 @@ static int mmc_blk_reset(struct mmc_blk_data *md, struct mmc_host *host,
> int type)
> {
> int err;
> + struct mmc_blk_data *main_md = dev_get_drvdata(&host->card->dev);
> + int part_err;
>
> if (md->reset_done & type)
> return -EEXIST;
>
> md->reset_done |= type;
> err = mmc_hw_reset(host->card);
> + if (err)
> + return err;
This could be a potential source of data corruption.
There is no guarantee that a subsequent I/O will fail just because
the reset failed. Reading / writing the wrong partition would be
disastrous, so we should always try to get back to the correct
partition.
I haven't looked at the possibility of just flagging the partition
as invalid - need to be sure any subsequent I/O attempts still go
through a path that switches the partition.
> /* Ensure we switch back to the correct partition */
> - if (err) {
> - struct mmc_blk_data *main_md =
> - dev_get_drvdata(&host->card->dev);
> - int part_err;
> -
> - main_md->part_curr = main_md->part_type;
> - part_err = mmc_blk_part_switch(host->card, md->part_type);
> - if (part_err) {
> - /*
> - * We have failed to get back into the correct
> - * partition, so we need to abort the whole request.
> - */
> - return -ENODEV;
> - }
> + main_md->part_curr = main_md->part_type;
> + part_err = mmc_blk_part_switch(host->card, md->part_type);
> + if (part_err) {
> + /*
> + * We have failed to get back into the correct
> + * partition, so we need to abort the whole request.
> + */
> + return -ENODEV;
> }
> - return err;
> + return 0;
> }
>
> static inline void mmc_blk_reset_success(struct mmc_blk_data *md, int type)
