linux-kernel - Re: [PATCH] mmc: block: remove the check for whole block device for ioctl.

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Date:	Wed, 16 Mar 2016 07:44:53 +0800
From:	"fengwei.yin" <fengwei.yin@...aro.org>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	jonathanh@...dia.com, ulf.hansson@...aro.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc: block: remove the check for whole block device for
 ioctl.



On 2016/3/15 22:31, Christoph Hellwig wrote:
> On Tue, Mar 15, 2016 at 11:26:07AM -0400, Yin, Fengwei wrote:
>> From: Fengwei Yin <fengwei.yin@...aro.org>
>>
>> a5f5774c55a2e3ed75f4d6c5556b7bfcb726e6f0 introduced the whole block
>> device checking for MMC_IOC_CMD while the old code has no such check.
>>
>> It breaks some ioctl call like BLKROSET from user space. An example
>> is "adb remount" cmd. It prints out following error message:
>> "remount of /system failed; couldn't make block device XXXX writable: \
>> Operation not permitted."
>> while the command worked fine.
>>
>> This change move the whole block device checking only for MMC_IOC_MULTI_CMD.
>
> I think mmc_blk_ioctl_cmd will need this as well, as will probably
> do any new ioctl.
>
> So I think the right fix is to simply return -EINVAL instead of
> EPERM if on a partition, which will make all the block layer ioctls
> works fine.
Fair enough.

I will wait for one more day for further comments to the patch. And update
the patch tomorrow. Thanks a lot for looking into the patch.

Regards
Yin, Fengwei

>