From: Kalle Valo <kvalo@codeaurora.org>
To: Lee Jones <lee.jones@linaro.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Christian Lamparter <chunkeey@gmail.com>,
davem@davemloft.net, kuba@kernel.org,
linux-kernel@vger.kernel.org,
Christian Lamparter <chunkeey@googlemail.com>,
Johannes Berg <johannes@sipsolutions.net>,
linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 08/30] net: wireless: ath: carl9170: Mark 'ar9170_qmap' as __maybe_unused
Date: Thu, 27 Aug 2020 10:54:21 +0300 [thread overview]
Message-ID: <87r1rsle1e.fsf@codeaurora.org> (raw)
In-Reply-To: <20200818095024.GZ4354@dell> (Lee Jones's message of "Tue, 18 Aug 2020 10:50:24 +0100")
Lee Jones <lee.jones@linaro.org> writes:
> On Mon, 17 Aug 2020, Kalle Valo wrote:
>
>> Rasmus Villemoes <linux@rasmusvillemoes.dk> writes:
>>
>> > On 14/08/2020 17.14, Christian Lamparter wrote:
>> >> On 2020-08-14 13:39, Lee Jones wrote:
>> >>> 'ar9170_qmap' is used in some source files which include carl9170.h,
>> >>> but not all of them. Mark it as __maybe_unused to show that this is
>> >>> not only okay, it's expected.
>> >>>
>> >>> Fixes the following W=1 kernel build warning(s)
>> >>
>> >> Is this W=1 really a "must" requirement? I find it strange having
>> >> __maybe_unused in header files as this "suggests" that the
>> >> definition is redundant.
>> >
>> > In this case it seems one could replace the table lookup with a
>> >
>> > static inline u8 ar9170_qmap(u8 idx) { return 3 - idx; }
>> >
>> > gcc doesn't warn about unused static inline functions (or one would have
>> > a million warnings to deal with). Just my $0.02.
>>
>> Yeah, this is much better.
>>
>> And I think that static variables should not even be in the header
>> files. Doesn't it mean that there's a local copy of the variable
>> everytime the .h file is included? Sure, in this case the overhead is
>> small (4 bytes per include) but still it's wrong.
>
> It happens a lot.
>
> As I stated before, the 2 viable options are to a) move it into the
> source files; ensuring code duplication, unnecessary maintenance
> burden and probably disparity over time, or b) create (or locate if
> there is one already) a special header file which is only to be
> included by the users.
>
> The later option gets really complicated if there are a variety of
> tables which are included by any given number of source file
> permutations.
>
> The accepted answer in all of the other subsystems I've worked with so
> far, is to use __maybe_unused. It's simple, non-intrusive and doesn't
> rely on any functional changes.
>
>> Having a static inline
>> function would solve that problem as well the compiler warning.
>
> This time yes, but it's a hack that will only work with simple,
> linear data.
To me __maybe_unused is a hack and a static inline function is a much
better solution.
> Try doing that with some of the other, more complicated
> tables, like mwifiex_sdio_sd8*.
Then the table should be moved to a .c file and the .h file should have
"extern const int foo[]"
--
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
next prev parent reply other threads:[~2020-08-27 7:55 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-14 11:39 [PATCH 00/30] Rid W=1 warnings in Networking Lee Jones
2020-08-14 11:39 ` [PATCH 01/30] net: bonding: bond_3ad: Fix a bunch of kerneldoc parameter issues Lee Jones
2020-08-14 11:39 ` [PATCH 02/30] net: bonding: bond_main: Document 'proto' and rename 'new_active' parameters Lee Jones
2020-08-14 11:39 ` [PATCH 03/30] net: ethernet: 3com: 3c574_cs: Remove set but unused variables 'tx' and 'rx' Lee Jones
2020-08-14 11:39 ` [PATCH 04/30] net: bonding: bond_alb: Describe alb_handle_addr_collision_on_attach()'s 'bond' and 'addr' params Lee Jones
2020-08-14 11:39 ` [PATCH 05/30] net: wireless: atmel: atmel: Demote non-kerneldoc header to standard comment block Lee Jones
2020-08-27 12:16 ` [PATCH 05/30] " Kalle Valo
2020-08-14 11:39 ` [PATCH 06/30] net: ethernet: 8390: axnet_cs: Document unused parameter 'txqueue' Lee Jones
2020-08-14 11:39 ` [PATCH 07/30] net: wireless: broadcom: b43: main: Add braces around empty statements Lee Jones
2020-08-14 15:12 ` Kalle Valo
2020-08-14 16:43 ` Lee Jones
2020-08-14 17:25 ` Kalle Valo
2020-08-17 8:50 ` Lee Jones
2020-08-27 7:42 ` Kalle Valo
2020-08-27 8:49 ` Lee Jones
2020-08-14 11:39 ` [PATCH 08/30] net: wireless: ath: carl9170: Mark 'ar9170_qmap' as __maybe_unused Lee Jones
2020-08-14 15:14 ` Christian Lamparter
2020-08-14 16:40 ` Lee Jones
2020-08-14 17:25 ` Christian Lamparter
2020-08-17 8:43 ` Lee Jones
2020-08-17 8:26 ` Rasmus Villemoes
2020-08-17 12:59 ` Kalle Valo
2020-08-17 18:29 ` Christian Lamparter
2020-08-18 9:50 ` Lee Jones
2020-08-27 7:54 ` Kalle Valo [this message]
2020-08-27 9:33 ` [PATCH v2 08/30] net: wireless: ath: carl9170: Convert 'ar9170_qmap' to inline function Lee Jones
2020-08-28 20:28 ` Christian Lamparter
2020-08-31 13:56 ` Kalle Valo
2020-08-31 15:19 ` Kalle Valo
2020-08-14 11:39 ` [PATCH 09/30] net: wireless: ath: ath5k: pcu: Add a description for 'band' remove one for 'mode' Lee Jones
2020-08-17 10:20 ` Kalle Valo
2020-08-14 11:39 ` [PATCH 10/30] net: wan: dlci: Remove set but not used variable 'err' Lee Jones
2020-08-14 11:39 ` [PATCH 11/30] net: wireless: cisco: airo: Place brackets around empty statement Lee Jones
2020-08-14 11:39 ` [PATCH 12/30] net: wireless: cisco: airo: Fix a myriad of coding style issues Lee Jones
2020-08-14 15:15 ` Kalle Valo
2020-08-14 16:38 ` Lee Jones
2020-08-17 13:27 ` Kalle Valo
2020-08-17 18:27 ` Jesse Brandeburg
2020-08-17 20:04 ` Lee Jones
2020-08-17 21:35 ` Ondrej Zary
2020-08-27 7:49 ` Kalle Valo
2020-08-27 20:23 ` Ondrej Zary
2020-08-28 8:59 ` Kalle Valo
2020-08-28 10:08 ` Lee Jones
2020-08-28 12:37 ` Kalle Valo
2020-08-28 21:34 ` Ondrej Zary
2020-08-14 11:39 ` [PATCH 13/30] net: wireless: ath: wil6210: cfg80211: Demote non-kerneldoc headers to standard comment blocks Lee Jones
2020-08-14 11:39 ` [PATCH 14/30] net: wireless: intel: iwlegacy: common: Remove set but not used variable 'len' Lee Jones
2020-08-14 11:39 ` [PATCH 15/30] net: wireless: intel: iwlegacy: common: Demote kerneldoc headers to standard comment blocks Lee Jones
2020-08-14 11:39 ` [PATCH 16/30] net: wireless: intel: ipw2200: Remove set but unused variables 'rc' and 'w' Lee Jones
2020-08-14 11:39 ` [PATCH 17/30] net: wireless: broadcom: b43legacy: main: Provide braces around empty 'if' body Lee Jones
2020-08-14 11:39 ` [PATCH 18/30] net: fddi: skfp: hwmtm: Remove seemingly unused variable 'ID_sccs' Lee Jones
2020-08-14 11:39 ` [PATCH 19/30] net: fddi: skfp: fplustm: " Lee Jones
2020-08-14 11:39 ` [PATCH 20/30] net: wireless: ath: ath5k: base: Fix kerneldoc formatting issue Lee Jones
2020-08-14 11:39 ` [PATCH 21/30] net: fddi: skfp: smt: Place definition of 'smt_pdef' under same stipulations as its use Lee Jones
2020-08-14 11:39 ` [PATCH 22/30] net: wireless: broadcom: brcm80211: brcmfmac: fweh: Remove set but unused variable 'err' Lee Jones
2020-08-14 11:39 ` [PATCH 23/30] net: wireless: broadcom: brcm80211: brcmfmac: fweh: Fix docrot related function documentation issues Lee Jones
2020-08-14 11:39 ` [PATCH 24/30] net: wireless: broadcom: brcm80211: brcmsmac: mac80211_if: Demote a few non-conformant kerneldoc headers Lee Jones
2020-08-14 11:39 ` [PATCH 25/30] net: wireless: intel: ipw2x00: ipw2200: Demote lots of nonconformant kerneldoc comments Lee Jones
2020-08-14 11:39 ` [PATCH 26/30] net: wireless: broadcom: b43: phy_common: Demote non-conformant kerneldoc header Lee Jones
[not found] ` <CAJrvBf00yQQ7F1p1utBuq1oWc2RwnqXijBjaJ+FuxG0mS0TvOA@mail.gmail.com>
2020-08-14 16:36 ` Lee Jones
2020-08-17 8:06 ` Rafał Miłecki
2020-08-17 9:11 ` Lee Jones
2020-08-14 11:39 ` [PATCH 27/30] net: fddi: skfp: smt: Remove seemingly unused variable 'ID_sccs' Lee Jones
2020-08-14 11:39 ` [PATCH 28/30] net: fddi: skfp: cfm: Remove set but unused variable 'oldstate' Lee Jones
2020-08-14 11:39 ` [PATCH 29/30] net: fddi: skfp: cfm: Remove seemingly unused variable 'ID_sccs' Lee Jones
2020-08-14 11:39 ` [PATCH 30/30] net: wireless: broadcom: b43: phy_n: Add empty braces around empty statements Lee Jones
2020-08-15 3:42 ` [PATCH 00/30] Rid W=1 warnings in Networking David Miller
2020-08-17 9:26 ` Lee Jones
2020-08-17 19:02 ` David Miller
2020-08-17 19:58 ` Lee Jones
[not found] ` <87eeo88pdr.fsf@tynnyri.adurom.net>
2020-08-17 8:16 ` Lee Jones
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