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

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Date:	Wed, 16 Mar 2016 21:49:35 +0800
From:	"fengwei.yin" <fengwei.yin@...aro.org>
To:	Jon Hunter <jonathanh@...dia.com>,
	Christoph Hellwig <hch@...radead.org>
Cc:	ulf.hansson@...aro.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc: block: remove the check for whole block device for
 ioctl.



On 2016/3/16 19:48, Jon Hunter wrote:
>
> On 15/03/16 23:44, fengwei.yin wrote:
>>
>>
>> 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.
>
> There is already a patch in the works for this [0].
>
> Cheers
> Jon
>
> [0] http://marc.info/?l=linux-mmc&m=145812340114153&w=2

Thanks a lot for the information. I will drop my patch.

Regards
Yin, Fengwei

>