From: Christoph Hellwig <hch@lst.de>
To: Nilay Shroff <nilay@linux.ibm.com>
Cc: "Yu Kuai" <yukuai@kernel.org>, "Jens Axboe" <axboe@kernel.dk>,
"Josef Bacik" <josef@toxicpanda.com>, "Tejun Heo" <tj@kernel.org>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Koutný" <mkoutny@suse.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Shuah Khan" <skhan@linuxfoundation.org>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Coly Li" <colyli@fygo.io>,
"Kent Overstreet" <kent.overstreet@linux.dev>,
"Alasdair Kergon" <agk@redhat.com>,
"Mike Snitzer" <snitzer@kernel.org>,
"Mikulas Patocka" <mpatocka@redhat.com>,
"Benjamin Marzinski" <bmarzins@redhat.com>,
"Song Liu" <song@kernel.org>,
"Li Nan" <magiclinan@didiglobal.com>, "Xiao Ni" <xiao@kernel.org>,
"Andreas Gruenbacher" <agruenba@redhat.com>,
"Matthew Wilcox" <willy@infradead.org>, "Jan Kara" <jack@suse.cz>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Chris Li" <chrisl@kernel.org>,
"Kairui Song" <kasong@tencent.com>,
"Kemeng Shi" <shikemeng@huaweicloud.com>,
"Nhat Pham" <nphamcs@gmail.com>,
"Baoquan He" <baoquan.he@linux.dev>,
"Barry Song" <baohua@kernel.org>,
"Youngjun Park" <youngjun.park@lge.com>,
"Nathan Chancellor" <nathan@kernel.org>,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Bill Wendling" <morbo@google.com>,
"Justin Stitt" <justinstitt@google.com>,
"Yu Kuai" <yukuai@fygo.io>, "Christoph Hellwig" <hch@lst.de>,
"Tao Cui" <cuitao@kylinos.cn>,
linux-block@vger.kernel.org, cgroups@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-bcache@vger.kernel.org, dm-devel@lists.linux.dev,
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llvm@lists.linux.dev
Subject: Re: [PATCH v2 3/3] blk-cgroup: move async bio punt state to blkcg
Date: Tue, 15 Sep 2026 08:50:44 +0200 [thread overview]
Message-ID: <20260915065044.GB13417@lst.de> (raw)
In-Reply-To: <f27ee89f-5a52-4cfc-a14a-e5019ae61d89@linux.ibm.com>
On Sun, Sep 13, 2026 at 06:59:25PM +0530, Nilay Shroff wrote:
>> + /* as long as there are pending bios, @blkcg can't go away */
>> + {
>> + guard(spinlock)(&blkcg->async_bio_lock);
>> + bio_list_merge_init(&bios, &blkcg->async_bios);
>> + }
>>
> Instead of using guard(spinlock)(...) here, I think we could use the
> simpler spin_lock()/spin_unlock() helpers. IMO, they are easier
> to read and reason about for these short critical sections.
Yes, guard() is a complete mess that makes code unreadable, please
don't use it. scope_guard is a bit better, but given that it doesn't
mix with goto based unwdinding it still is too dangerous to actually
use.
next prev parent reply other threads:[~2026-09-15 6:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-13 6:54 [PATCH v2 0/3] blk-cgroup: store blkcg in bio before blkcg_mutex conversion Yu Kuai
2026-09-13 6:54 ` [PATCH v2 1/3] blk-cgroup: use a request_queue rhashtable for blkg lookup Yu Kuai
2026-09-13 6:54 ` [PATCH v2 2/3] blk-cgroup: store blkcg in bio instead of blkg Yu Kuai
2026-09-13 13:06 ` Nilay Shroff
2026-09-15 6:49 ` Christoph Hellwig
2026-09-15 15:43 ` yu kuai
2026-09-13 6:54 ` [PATCH v2 3/3] blk-cgroup: move async bio punt state to blkcg Yu Kuai
2026-09-13 13:29 ` Nilay Shroff
2026-09-15 6:50 ` Christoph Hellwig [this message]
2026-09-15 15:54 ` yu kuai
2026-09-16 5:46 ` Nilay Shroff
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