From: George Stark <gnstark@salutedevices.com>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
Waiman Long <longman@redhat.com>,
"andy.shevchenko@gmail.com" <andy.shevchenko@gmail.com>,
"pavel@ucw.cz" <pavel@ucw.cz>, "lee@kernel.org" <lee@kernel.org>,
"vadimp@nvidia.com" <vadimp@nvidia.com>,
"mpe@ellerman.id.au" <mpe@ellerman.id.au>,
"npiggin@gmail.com" <npiggin@gmail.com>,
"hdegoede@redhat.com" <hdegoede@redhat.com>,
"mazziesaccount@gmail.com" <mazziesaccount@gmail.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"will@kernel.org" <will@kernel.org>,
"boqun.feng@gmail.com" <boqun.feng@gmail.com>,
"nikitos.tr@gmail.com" <nikitos.tr@gmail.com>
Cc: "linux-leds@vger.kernel.org" <linux-leds@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"kernel@salutedevices.com" <kernel@salutedevices.com>
Subject: Re: [PATCH v4 02/10] locking: introduce devm_mutex_init
Date: Mon, 18 Dec 2023 16:26:30 +0300 [thread overview]
Message-ID: <d160443b-b973-4162-9900-95c04e62cd65@salutedevices.com> (raw)
In-Reply-To: <0a81e53d-f837-486c-8b0b-7a3c62853be7@csgroup.eu>
Hello Christophe
On 12/17/23 12:31, Christophe Leroy wrote:
...
>>>>>>> ---
>>>>>>> include/linux/mutex.h | 23 +++++++++++++++++++++++
>>>>>>> kernel/locking/mutex-debug.c | 22 ++++++++++++++++++++++
>>>>>>> 2 files changed, 45 insertions(+)
>>>>>>>
>>>>>>> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
>>>>>>> index a33aa9eb9fc3..ebd03ff1ef66 100644
>>>>>>> --- a/include/linux/mutex.h
>>>>>>> +++ b/include/linux/mutex.h
>>>>>>> @@ -21,6 +21,8 @@
>>>>>>> #include <linux/debug_locks.h>
>>>>>>> #include <linux/cleanup.h>
>>>>>>> +struct device;
>>>>>>> +
>>>>>>> #ifdef CONFIG_DEBUG_LOCK_ALLOC
>>>>>>> # define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
>>>>>>> , .dep_map = { \
>>>>>>> @@ -127,6 +129,20 @@ extern void __mutex_init(struct mutex *lock,
>>>>>>> const char *name,
>>>>>>> */
>>>>>>> extern bool mutex_is_locked(struct mutex *lock);
>>>>>>> +#ifdef CONFIG_DEBUG_MUTEXES
>>>>>>> +
>>>>>>> +int devm_mutex_init(struct device *dev, struct mutex *lock);
>>>>>> Please add "extern" to the function declaration to be consistent with
>>>>>> other functional declarations in mutex.h.
>>>>> 'extern' is pointless and deprecated on function prototypes. Already
>>>>> having some is not a good reason to add new ones, errors from the past
>>>>> should be avoided nowadays. With time they should all disappear so
>>>>> don't
>>>>> add new ones.
>>>> Yes, "extern" is optional. It is just a suggestion and I am going to
>>>> argue about that.
>>>
>>> FWIW, note that when you perform a strict check with checkpatch.pl, you
>>> get a warning for that:
>>>
>>> $ ./scripts/checkpatch.pl --strict -g HEAD
>>> CHECK: extern prototypes should be avoided in .h files
>>> #56: FILE: include/linux/mutex.h:131:
>>> +extern int devm_mutex_init(struct device *dev, struct mutex *lock);
>>>
>>> total: 0 errors, 0 warnings, 1 checks, 99 lines checked
>>
>> This is ambiguous situation about extern. It's deprecated and useless on
>> one hand but harmless. And those externs will not disappear by themself
>> - it'll be one patch that clean them all at once (in one header at
>> least) so one more extern will not alter the overall picture.
>
> That kind of cleanup patch bomb is a nightmare for backporting, so if it
> happens one day it should be as light as possible, hence the importance
> to not add new ones and remove existing one everytime you modify or move
> a line including it for whatever reason.
>
>>
>> On the other hand if we manage to place devm_mutex_init near
>> mutex_destroy then we'll have:
>>
>> int devm_mutex_init(struct device *dev, struct mutex *lock);
>> extern void mutex_destroy(struct mutex *lock);
>
> I sent you an alternative proposal that avoids duplication of the static
> inline version of devm_mutex_init(). If you agree with it just take it
> into your series and that question will vanish.
Thanks for that patch by the way. The only comment is that moving
mutex_destroy
should be done in a separate patch IMO.
Waiman Long proposed such a refactoring here:
https://lore.kernel.org/lkml/20231216013656.1382213-2-longman@redhat.com/T/
With this patch adding devm_mutex_init would be straightforward.
>>
>> and it raises questions and does not look very nice.
>
> If you look at linux/mm.h there are plenty of them anyway, so why do
> different ? For an exemple look at
> https://elixir.bootlin.com/linux/v6.7-rc4/source/include/linux/mm.h#L2372
Oh, I see. Ok, I don't have any more arguments against removing extern.
We'll see what mutex.h maintainers decide.
>
> Christophe
--
Best regards
George
next prev parent reply other threads:[~2023-12-18 13:34 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-14 17:36 [PATCH v4 00/10] devm_led_classdev_register() usage problem George Stark
2023-12-14 17:36 ` [PATCH v4 01/10] leds: aw2013: unlock mutex before destroying it George Stark
2024-02-23 15:07 ` (subset) " Lee Jones
2023-12-14 17:36 ` [PATCH v4 02/10] locking: introduce devm_mutex_init George Stark
2023-12-14 18:48 ` Waiman Long
2023-12-14 19:53 ` Christophe Leroy
2023-12-14 21:48 ` Waiman Long
2023-12-15 5:46 ` Christophe Leroy
2023-12-17 1:05 ` George Stark
2023-12-17 9:31 ` Christophe Leroy
2023-12-18 13:26 ` George Stark [this message]
2023-12-14 19:47 ` Christophe Leroy
2023-12-15 6:22 ` [PATCH RFC v4-bis] " Christophe Leroy
2023-12-15 15:58 ` Andy Shevchenko
2023-12-15 17:51 ` Christophe Leroy
2023-12-16 1:30 ` Waiman Long
2023-12-14 17:36 ` [PATCH v4 03/10] leds: aw2013: use devm API to cleanup module's resources George Stark
2023-12-14 17:36 ` [PATCH v4 04/10] leds: aw200xx: " George Stark
2023-12-14 17:36 ` [PATCH v4 05/10] leds: lp3952: " George Stark
2023-12-14 17:36 ` [PATCH v4 06/10] leds: lm3532: " George Stark
2023-12-14 17:36 ` [PATCH v4 07/10] leds: nic78bx: " George Stark
2023-12-14 17:36 ` [PATCH v4 08/10] leds: mlxreg: use devm_mutex_init for mutex initializtion George Stark
2023-12-14 17:36 ` [PATCH v4 09/10] leds: an30259a: use devm_mutext_init for mutext initialization George Stark
2023-12-14 17:36 ` [PATCH v4 10/10] leds: powernv: use LED_RETAIN_AT_SHUTDOWN flag for leds George Stark
2023-12-21 15:11 ` [PATCH v4 00/10] devm_led_classdev_register() usage problem Lee Jones
2024-02-09 17:11 ` Andy Shevchenko
2024-02-11 23:52 ` [DMARC error][SPF error] " George Stark
2024-02-12 9:53 ` Andy Shevchenko
2024-02-13 0:14 ` George Stark
2024-02-13 10:55 ` Andy Shevchenko
2024-02-13 23:56 ` George Stark
2024-02-09 17:17 ` Andy Shevchenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=d160443b-b973-4162-9900-95c04e62cd65@salutedevices.com \
--to=gnstark@salutedevices.com \
--cc=andy.shevchenko@gmail.com \
--cc=boqun.feng@gmail.com \
--cc=christophe.leroy@csgroup.eu \
--cc=hdegoede@redhat.com \
--cc=kernel@salutedevices.com \
--cc=lee@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-leds@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=longman@redhat.com \
--cc=mazziesaccount@gmail.com \
--cc=mingo@redhat.com \
--cc=mpe@ellerman.id.au \
--cc=nikitos.tr@gmail.com \
--cc=npiggin@gmail.com \
--cc=pavel@ucw.cz \
--cc=peterz@infradead.org \
--cc=vadimp@nvidia.com \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).