linux-kernel - Re: [PATCH RFC md-6.16 v3 02/19] md: support discard for bitmap ops

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <7bfc4eb5-8f6f-663c-f1e2-faf6c1690866@huaweicloud.com>
Date: Mon, 12 May 2025 14:22:53 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: Christoph Hellwig <hch@....de>, Yu Kuai <yukuai1@...weicloud.com>
Cc: xni@...hat.com, colyli@...nel.org, agk@...hat.com, snitzer@...nel.org,
 mpatocka@...hat.com, song@...nel.org, linux-kernel@...r.kernel.org,
 dm-devel@...ts.linux.dev, linux-raid@...r.kernel.org, yi.zhang@...wei.com,
 yangerkun@...wei.com, johnny.chenyi@...wei.com,
 "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [PATCH RFC md-6.16 v3 02/19] md: support discard for bitmap ops

Hi,

在 2025/05/12 14:12, Christoph Hellwig 写道:
> On Mon, May 12, 2025 at 02:05:56PM +0800, Yu Kuai wrote:
>>>>    -	mddev->bitmap_ops->startwrite(mddev, md_io_clone->offset,
>>>> -				      md_io_clone->sectors);
>>>> +	if (unlikely(md_io_clone->rw == STAT_DISCARD) &&
>>>> +	    mddev->bitmap_ops->start_discard)
>>>> +		mddev->bitmap_ops->start_discard(mddev, md_io_clone->offset,
>>>> +						 md_io_clone->sectors);
>>>> +	else
>>>> +		mddev->bitmap_ops->startwrite(mddev, md_io_clone->offset,
>>>> +					      md_io_clone->sectors);
>>>>    }
>>>
>>> This interface feels weird, as it would still call into the write
>>> interfaces when the discard ones are not defined instead of doing
>>> nothing.  Also shouldn't discard also use a different interface
>>> than md_bitmap_start in the caller?
>>
>> This is because the old bitmap handle discard the same as write, I
>> can't do nothing in this case. Do you prefer also reuse the write
>> api to new discard api for old bitmap?
> 
> It can just point the discard method to the same function as the
> existing write one.

Yes, this is exactly want I mean, I'll update this in the next version.

Thanks,
Kuai

> 
> .
>