Messages in this thread | | | Subject | Re: [RESENT PATCH] mmc: block: fix ABI regression of mmc_blk_ioctl | From | Shawn Lin <> | Date | Wed, 9 Mar 2016 21:51:29 +0800 |
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On 2016/3/9 18:50, Jon Hunter wrote: > > On 07/03/16 06:59, Shawn Lin 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 > > I think you should elaborate here why the behaviour between -EINVAL and > -EPERM is different as they are both errors. In other words, add your > comment about how the ADB code is checking for a supported command.
yep. So if need to send v2 after comment from Ulf, I will add more into commit-msg.
> >> 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@vger.kernel.org >> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com> >> --- >> >> drivers/mmc/card/block.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c >> index 47bc87d..170f099 100644 >> --- a/drivers/mmc/card/block.c >> +++ b/drivers/mmc/card/block.c >> @@ -688,6 +688,9 @@ cmd_err: >> static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode, >> unsigned int cmd, unsigned long arg) >> { >> + if (cmd != MMC_IOC_CMD && cmd != MMC_IOC_MULTI_CMD) >> + return -EINVAL; >> + >> /* >> * The caller must have CAP_SYS_RAWIO, and must be calling this on the >> * whole block device, not on a partition. This prevents overspray > > The change is fine with me, but I agree with Seshagiri's comment that > instead of the above, move the following test to the mmc_blk_ioctl_cmd > and mmc_blk_ioctl_multi_cmd functions: > > if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains)) > return -EPERM; >
right, and both are ok to me :). Adding this check for mmc_blk_ioctl_cmd and mmc_blk_ioctl_multi_cmd respectively may also looks like we produce two some code sections that do the same thing.
I think it depends on how Ulf want the solution to be? Let's wait for Ulf' comment.
> There is a case statement that then would return -EINVAL if the command > is not supported. > > If you look at V3 of the patch "mmc: block: Add new ioctl to send multi > commands" [0] this is how we had it and only in V4 (the final version) > did we move it.
yes, I read V3 and V4 both to see how the patch was going. Thanks for sharing it.
> > Cheers > Jon > > [0] http://marc.info/?l=linux-mmc&m=144224289716299&w=2 > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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