linux-kernel - Re: [PATCH v2] iwlwifi: mvm: Use div_s64 instead of do_div in iwl_mvm_debug_range

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Date:   Fri, 22 Feb 2019 09:52:24 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Nathan Chancellor <natechancellor@...il.com>,
        Johannes Berg <johannes.berg@...el.com>,
        Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
        Luca Coelho <luciano.coelho@...el.com>,
        Intel Linux Wireless <linuxwifi@...el.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        Networking <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] iwlwifi: mvm: Use div_s64 instead of do_div in iwl_mvm_debug_range_resp

On Fri, Feb 22, 2019 at 1:14 AM Nick Desaulniers
<ndesaulniers@...gle.com> wrote:
> On Thu, Feb 21, 2019 at 12:08 AM Nathan Chancellor <natechancellor@...il.com> wrote:

> One thing I'm curious about, is "why does do_div exist?" When should I
> use do_div vs div_u64 (not div_s64 as is used in this patch)?

I think do_div() is mostly historic, we've had it since the early days
when C compilers were not as good with inline functions. The various
other versions are regular functions, and I tend to prefer them for new
code, but do_div() is widely known and documented, so I have little
hope of it going away any time soon.

       Arnd