Hi Wan, 2014-05-19 9:55 GMT+02:00 Wan ZongShun <mcuos....@gmail.com>: > Hi all, > > I have a question for mmc_blk_ioctl_cmd. > > I did not see any sync code in this function like mutex, semphere.., why? > The ioctl will do partition switch as I know, so If more partitions > call the ioctl from user layer at the same time, how to sync with > them?
I guess because locking here could result in deadlocks when the device is accessed from for instance the block driver. There is no guarantee that any commands you send to the card via consecutive calls to the ioctl interface are not interlaced by other commands sent via the block driver or other ioctl calls. Kind regards, Johan -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
