• Ding Wang's avatar
    mmc: card: Fixup request missing in mmc_blk_issue_rw_rq · 29535f7b
    Ding Wang authored
    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: default avatarDing Wang <justin.wang@spreadtrum.com>
    Fixes: 67716327 ("mmc: block: add eMMC hardware reset support")
    Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
    29535f7b
block.c 65.1 KB