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From:   Cong Wang <xiyou.wangcong@gmail.com>
Date:   Wed, 3 Apr 2019 15:55:20 -0700
Message-ID: <CAM_iQpU2qwezhk8XdnX+kvUi8Oi0mwNxRuFOo8uGvjZaPZGNWA@mail.gmail.com>
Subject: Re: [PATCH] Bluetooth: hci_event: potential out of bounds parsing ADV events
To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     Tomas Bortoli <tomasbortoli@gmail.com>,
        Marcel Holtmann <marcel@holtmann.org>,
        Jaganath Kanakkassery <jaganath.k.os@gmail.com>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        linux-bluetooth <linux-bluetooth@vger.kernel.org>,
        kernel-janitors@vger.kernel.org
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On Tue, Apr 2, 2019 at 1:51 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> On Tue, Apr 02, 2019 at 10:42:38AM -0700, Cong Wang wrote:
> > I think these likely()/unlikely() are reasonable, ill-formatted packets
> > are rare cases, normal packets deserve such a special care. We
> > use likely()/unlikely() with pskb_may_pull() in many places in
> > networking subsystem, at least.
>
> The likely()/unlikely() annotations are to help the compiler optimize
> the fast path.  They are not there just for decorating the code.  We
> should only use likely()/unlikely() where it makes a difference in
> benchmarking.  Otherwise it's just a style question, right (obviously)?

That is not a requirement.

Unless you have a strong argument to believe likely()/unlikely()
doesn't help in this specific case (ill-formatted packets), we should
by default use it.

Coding style is not a strong argument, it is purely a taste. At least,
does CodingStyle forbid to use it in this case? I tried checkpatch.pl,
it has no such a complain.

Thanks.