On 12 June 2015 at 14:38, Justin Wang (王丁) <Justin.Wang@xxxxxxxxxxxxxx> wrote:
> From 0e01e7546745f39843d54810f74c198e01cb8226 Mon Sep 17 00:00:00 2001
> From: justin.wang <justin.wang@xxxxxxxxxxxxxx>
> Date: Mon, 18 May 2015 20:14:15 +0800
> Subject: [PATCH v2] mmc: card: Fixup request missing in mmc_blk_issue_rw_rq
>
> The current handler of MMC_BLK_CMD_ERR in mmc_blk_issue_rw_rq function
> may cause new coming request permanent missing when the ongoing
> request (previoulsy started) complete end.
>
> The problem scenario is as follows:
> (1) Request A is ongoing;
> (2) Request B arrived, and finally mmc_blk_issue_rw_rq() is called;
> (3) Request A encounters the MMC_BLK_CMD_ERR error;
> (4) In the error handling of MMC_BLK_CMD_ERR, suppose mmc_blk_cmd_err()
> end request A completed and return zero. Continue the error handling,
> suppose mmc_blk_reset() reset device success;
> (5) Continue the execution, while loop completed because variable ret
> is zero now;
> (6) Finally, mmc_blk_issue_rw_rq() return without processing request B.
>
> The process related to the missing request may wait that IO request
> complete forever, possibly crashing the application or hanging the system.
>
> Fix this issue by starting new request when reset success.
>
> Signed-off-by: Ding Wang <justin.wang@xxxxxxxxxxxxxx>
Thanks, applied for next.
I have added a the following fixes tag:
Fixes 67716327eec7 ("mmc: block: add eMMC hardware reset support")
I am not sure, whether the bug were introduced even earlier than that,
but I think $subject patch should be trivial to apply on top that one.
Kind regards
Uffe
> ---
> drivers/mmc/card/block.c | 8 +++++---
> 1 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 60f7141..f05cd1f 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -1910,9 +1910,11 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
> break;
> case MMC_BLK_CMD_ERR:
> ret = mmc_blk_cmd_err(md, card, brq, req, ret);
> - if (!mmc_blk_reset(md, card->host, type))
> - break;
> - goto cmd_abort;
> + if (mmc_blk_reset(md, card->host, type))
> + goto cmd_abort;
> + if (!ret)
> + goto start_new_req;
> + break;
> case MMC_BLK_RETRY:
> if (retry++ < 5)
> break;
> --
> 1.7.4.1
>
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