[PATCH v2] mtd: mtd_blkdevs: Initialize rq.limits.discard_granularity

[Zhihao Cheng]

在 2021/6/18 16:55, Zhihao Cheng 写道:
> 在 2021/6/18 15:52, Miquel Raynal 写道:
>> Hi Zhihao,
>>
>> Zhihao Cheng <chengzhihao1 at huawei.com> wrote on Tue, 15 Jun 2021
>> 17:39:05 +0800:
>>
>>> Since commit b35fd7422c2f8("block: check queue's 
>>> limits.discard_granularity
>>> in __blkdev_issue_discard()") checks rq.limits.discard_granularity in
>>> __blkdev_issue_discard(), we may get following warnings on formatted 
>>> ftl:
>>>
>>>    WARNING: CPU: 2 PID: 7313 at block/blk-lib.c:51
>>>    __blkdev_issue_discard+0x2a7/0x390
>>>
>>> Reproducer:
>>>    1. ftl_format /dev/mtd0
>>>    2. modprobe ftl
>>>    3. mkfs.vfat /dev/ftla
>>>    4. mount -odiscard /dev/ftla temp
>>>    5. dd if=/dev/zero of=temp/tst bs=1M count=10 oflag=direct
>>>    6. dd if=/dev/zero of=temp/tst bs=1M count=10 oflag=direct
>>>
>>> Fix it by initializing rq.limits.discard_granularity if device supports
>>> discard operation.
>>
>> Can you please verify that this is still needed after Christoph's
>> additional fix:
>> https://patchwork.kernel.org/project/xen-devel/patch/20210602065345.355274-10-hch@lst.de/ 
>>
>>
> Hi, Miquel,
> I can still reproduce the problem after [1] applied.
> I look through this series patches and I didn't find out 
> 'rq.limits.discard_granularity' has been initialized somewhere. The 
> patchset is aming at reconstructing to avoid boilerplate code in drivers?
> So 'rq.limits.discard_granularity' still need to be initialized in 
> mtdblock driver.
>
> [1] 
> https://patchwork.kernel.org/project/xen-devel/patch/20210602065345.355274-10-hch@lst.de/
>
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