Re: [RESENT PATCH] mmc: block: fix ABI regression of mmc_blk_ioctl

From: John Stultz
Date: Wed Mar 09 2016 - 02:55:31 EST

On Mon, Mar 7, 2016 at 1:59 PM, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
> We should return -EINVAL if cmd is not MMC_IOC_CMD or MMC_IOC_MULTI_CMD,
> otherwise blkdev_roset will return -EPERM.
> Android-adb calls make_block_device_writable with ioctl(BLKROSET), which
> will return error, make remount failed:
> remount of /system failed;
> couldn't make block device writable: Operation not permitted
> openat(AT_FDCWD, "/dev/block/platform/ff420000.dwmmc/by-name/system", O_RDONLY) = 3
> ioctl(3, BLKROSET, 0) = -1 EPERM (Operation not permitted)
> Fixes: a5f5774c55a2 ("mmc: block: Add new ioctl to send multi commands")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>

We're hitting this as well, and Shawn's patch seems to fix it for me.

Tested-by: John Stultz <john.stultz@xxxxxxxxxx>

Thanks Shawn!