linux-kernel - Re: [PATCH -next v3 6/7] md/raid1-10: don't handle pluged bio by daemon thread

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]

Date:   Wed, 31 May 2023 09:57:54 +0200
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Yu Kuai <yukuai1@...weicloud.com>
Cc:     song@...nel.org, neilb@...e.de, akpm@...l.org, xni@...hat.com,
        linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org,
        yukuai3@...wei.com, yi.zhang@...wei.com, yangerkun@...wei.com
Subject: Re: [PATCH -next v3 6/7] md/raid1-10: don't handle pluged bio by
 daemon thread

Dear Yu,


Thank you for your patch. Some minor nits in case you should resend this.

In the summary/title it should be plug*g*ed.

Am 29.05.23 um 15:11 schrieb Yu Kuai:
> From: Yu Kuai <yukuai3@...wei.com>
> 
> current->bio_list will be set under submit_bio() context, in this case
> bitmap io will be added to the list and wait for current io submission to

1.  I’d use present tense: s/will be set/is set/; s/will be added/is added/
2.  wait*s*

> finish, while current io submission must wait for bitmap io to be done.
> commit 874807a83139 ("md/raid1{,0}: fix deadlock in bitmap_unplug.") fix
> the deadlock by handling plugged bio by daemon thread.
> 
> On the one hand, the deadlock won't exist after commit a214b949d8e3
> ("blk-mq: only flush requests from the plug in blk_mq_submit_bio"). On
> the other hand, current solution makes it impossible to flush plugged bio
> in raid1/10_make_request(), because this will cause that all the writes
> will goto daemon thread.

s/goto/go to/


Kind regards,

Paul


> In order to limit the number of plugged bio, commit 874807a83139
> ("md/raid1{,0}: fix deadlock in bitmap_unplug.") is reverted, and the
> deadlock is fixed by handling bitmap io asynchronously.
> 
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> ---
>   drivers/md/raid1-10.c | 14 ++++++++++++++
>   drivers/md/raid1.c    |  4 ++--
>   drivers/md/raid10.c   |  8 +++-----
>   3 files changed, 19 insertions(+), 7 deletions(-)

[…]