From: Gabriel Krisman Bertazi <krisman@suse.de>
To: Alok Tiwari <alok.a.tiwari@oracle.com>
Cc: csander@purestorage.com, axboe@kernel.dk,
io-uring@vger.kernel.org, alok.a.tiwarilinux@gmail.com
Subject: Re: [PATCH v2] io_uring: fix incorrect unlikely() usage in io_waitid_prep()
Date: Mon, 20 Oct 2025 11:00:01 -0400 [thread overview]
Message-ID: <87h5vt39fy.fsf@mailhost.krisman.be> (raw)
In-Reply-To: <20251018193300.1517312-1-alok.a.tiwari@oracle.com> (Alok Tiwari's message of "Sat, 18 Oct 2025 12:32:54 -0700")
Alok Tiwari <alok.a.tiwari@oracle.com> writes:
> The negation operator incorrectly places outside the unlikely() macro:
>
> if (!unlikely(iwa))
>
> This inverted the compiler branch prediction hint, marking the NULL
> case as likely instead of unlikely. The intent is to indicate that
> allocation failures are rare, consistent with common kernel patterns.
>
> Moving the negation inside unlikely():
>
> if (unlikely(!iwa))
>
> Fixes: 2b4fc4cd43f2 ("io_uring/waitid: setup async data in the prep handler")
> Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
--
Gabriel Krisman Bertazi
next prev parent reply other threads:[~2025-10-20 15:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-18 19:32 [PATCH v2] io_uring: fix incorrect unlikely() usage in io_waitid_prep() Alok Tiwari
2025-10-19 16:27 ` Caleb Sander Mateos
2025-10-20 15:23 ` Jens Axboe
2025-10-20 15:00 ` Gabriel Krisman Bertazi [this message]
2025-10-20 15:22 ` Jens Axboe
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