linux-kernel - Re: [PATCH] block: Remove unnecessary unlikely()

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: <fe1f4fe8-48d8-4b09-bd50-36e8fd8e75cb@kernel.dk>
Date: Fri, 19 Jan 2024 09:41:40 -0700
From: Jens Axboe <axboe@...nel.dk>
To: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
 Linus Torvalds <torvalds@...ux-foundation.org>, linux-block@...r.kernel.org,
 linux-kernel@...r.kernel.org
Cc: stable@...r.kernel.org
Subject: Re: [PATCH] block: Remove unnecessary unlikely()

On 1/19/24 9:34 AM, Matthew Wilcox (Oracle) wrote:
> Jens added unlikely() thinking that this was an error path.  It's
> actually just the end of the iteration, so does not warrant an
> unlikely().

This is because the previous fix (or my attempt at least) didn't do the
i >= vcnt, it checked for an empty bio instead. Which then definitely
did make it an error/unlikely path, but obviously this one is not.

The bio iterator stuff has gotten terribly unwieldy and complicated, and
not very efficient either. But I guess that's a story for another
investigation...

-- 
Jens Axboe