mmc: block: fix ABI regression of mmc_blk_ioctl
authorShawn Lin <shawn.lin@rock-chips.com>
Wed, 16 Mar 2016 10:15:47 +0000 (18:15 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 12 Apr 2016 16:09:01 +0000 (09:09 -0700)
commitd69bc6d28c9662bde7230d88e405c8694d05d94c
tree79a1df5af4c2e8daac5e8eb2a565eca36547fbe1
parent65b55d179b275cec668b2fffa23f884b55575726
mmc: block: fix ABI regression of mmc_blk_ioctl

commit 83c742c344c08c2bbe338d45c6ec63110e9d5e3d upstream.

If mmc_blk_ioctl returns -EINVAL, blkdev_ioctl continues to
work without returning err to user-space. But now we check
CAP_SYS_RAWIO firstly, so we return -EPERM to blkdev_ioctl,
which make blkdev_ioctl return -EPERM to user-space directly.
So this will break all the ioctl with BLKROSET. Now we find
Android-adb suffer it for the following log:

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")
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/mmc/card/block.c