• G
    mmc: block: Let MMC_IOC_MULTI_CMD return zero again for zero entries · aab2ee03
    Geert Uytterhoeven 提交于
    With gcc 4.1.2:
    
        drivers/mmc/core/block.c: In function ‘mmc_blk_ioctl_cmd_issue’:
        drivers/mmc/core/block.c:630: warning: ‘ioc_err’ may be used uninitialized in this function
    
    Indeed, if mq_rq->ioc_count is zero, an uninitialized value will be
    stored in mq_rq->drv_op_result and passed to blk_end_request_all().
    
    Can mq_rq->ioc_count be zero?
      - mmc_blk_ioctl_cmd() sets ioc_count to 1, so this is safe,
      - mmc_blk_ioctl_multi_cmd() obtains ioc_count from user space in
        response to the MMC_IOC_MULTI_CMD ioctl, and does allow zero.
    
    To avoid returning an uninitialized value, and as it is pointless to do
    all this work when the MMC_IOC_MULTI_CMD ioctl is used with zero
    entries, check for this early in mmc_blk_ioctl_multi_cmd(), and return
    zero, like was returned before.
    
    Fixes: 3ecd8cf2 ("mmc: block: move multi-ioctl() to use block layer")
    Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
    Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
    aab2ee03
block.c 59.4 KB