linux-kernel - Re: [PATCH] watchdog: delete old declarations for watchdog_soft,hardlockup_user

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Date:   Fri, 26 May 2023 05:53:51 -0700
From:   Tom Rix <trix@...hat.com>
To:     Douglas Anderson <dianders@...omium.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Petr Mladek <pmladek@...e.com>,
        Mukesh Ojha <quic_mojha@...cinc.com>,
        Laurent Dufour <ldufour@...ux.ibm.com>,
        Lecopzer Chen <lecopzer.chen@...iatek.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Pingfan Liu <kernelfans@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] watchdog: delete old declarations for
 watchdog_soft,hardlockup_user_enabled + make static


On 5/25/23 4:28 PM, Douglas Anderson wrote:
> From: Tom Rix <trix@...hat.com>
>
> smatch reports
> kernel/watchdog.c:40:19: warning: symbol
>    'watchdog_hardlockup_user_enabled' was not declared. Should it be static?
> kernel/watchdog.c:41:19: warning: symbol
>    'watchdog_softlockup_user_enabled' was not declared. Should it be static?
>
> These variables are only used in their defining file, so they should
> be static.
>
> This problem showed up after the patch ("watchdog/hardlockup: rename
> some "NMI watchdog" constants/function") because that rename missed
> the header file. That didn't cause any compile-time errors because,
> since commit dd0693fdf054 ("watchdog: move watchdog sysctl interface
> to watchdog.c"), nobody outside of "watchdog.c" was actually referring
> to them. Thus, not only should we make these variables static but we
> should remove the old declarations in the header file that we missed
> renaming.
>
> Fixes: 4b95b620dcd5 ("watchdog/hardlockup: rename some "NMI watchdog" constants/function")
> Signed-off-by: Tom Rix <trix@...hat.com>
> [dianders: updated subject + commit message; squashed in Petr's suggestion]
> Suggested-by: Petr Mladek <pmladek@...e.com>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> ---
> This is a squash of two patches that were posted to mailing lists, one
> official patch posted by Tom [1] and one that was posted in reply to
> my previous patch by Petr [2].
>
> IMO it makes sense to put these two things into one patch since
> they're basically dealing with the same issue. As promised [3] I'm
> posting the squash of the two patches.
>
> I have no idea how to really tag this and set authorship. I've chosen
> to leave author/Signed-off-by from Tom. Peter didn't officially
> include his Singed-off-by on his patch (as is common when posting
> suggestions in reply to another patch), so I didn't add it but added a
> Suggested-by from him. Hopefully this is OK. I dropped Mukesh's
> Reviewed-by just because it felt like things changed enough with the
> addition of Petr's stuff that it should be re-added.
>
> I've tagged this as "Fixes" based on the git hash in the current
> linuxnext.
>
> [1] https://lore.kernel.org/r/20230523122324.1668396-1-trix@redhat.com
> [2] https://lore.kernel.org/r/ZG4TW--j-DdSsUO6@alley/
> [3] https://lore.kernel.org/all/CAD=FV=V_i5wR4oNy+xarA9e=VcgpH6i3U1uxFKtsaOe5AQX=Zw@mail.gmail.com/
>
>   include/linux/nmi.h | 6 ++----
>   kernel/watchdog.c   | 4 ++--
>   2 files changed, 4 insertions(+), 6 deletions(-)

Looks good to me.

Reviewed-by: Tom Rix <trix@...hat.com>

>
> diff --git a/include/linux/nmi.h b/include/linux/nmi.h
> index d23902a2fd49..333465e235e1 100644
> --- a/include/linux/nmi.h
> +++ b/include/linux/nmi.h
> @@ -18,8 +18,6 @@ void lockup_detector_soft_poweroff(void);
>   void lockup_detector_cleanup(void);
>   
>   extern int watchdog_user_enabled;
> -extern int nmi_watchdog_user_enabled;
> -extern int soft_watchdog_user_enabled;
>   extern int watchdog_thresh;
>   extern unsigned long watchdog_enabled;
>   
> @@ -70,8 +68,8 @@ static inline void reset_hung_task_detector(void) { }
>    * 'watchdog_enabled' variable. Each lockup detector has its dedicated bit -
>    * bit 0 for the hard lockup detector and bit 1 for the soft lockup detector.
>    *
> - * 'watchdog_user_enabled', 'nmi_watchdog_user_enabled' and
> - * 'soft_watchdog_user_enabled' are variables that are only used as an
> + * 'watchdog_user_enabled', 'watchdog_hardlockup_user_enabled' and
> + * 'watchdog_softlockup_user_enabled' are variables that are only used as an
>    * 'interface' between the parameters in /proc/sys/kernel and the internal
>    * state bits in 'watchdog_enabled'. The 'watchdog_thresh' variable is
>    * handled differently because its value is not boolean, and the lockup
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index 877d8670f26e..237990e8d345 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -37,8 +37,8 @@ static DEFINE_MUTEX(watchdog_mutex);
>   
>   unsigned long __read_mostly watchdog_enabled;
>   int __read_mostly watchdog_user_enabled = 1;
> -int __read_mostly watchdog_hardlockup_user_enabled = WATCHDOG_HARDLOCKUP_DEFAULT;
> -int __read_mostly watchdog_softlockup_user_enabled = 1;
> +static int __read_mostly watchdog_hardlockup_user_enabled = WATCHDOG_HARDLOCKUP_DEFAULT;
> +static int __read_mostly watchdog_softlockup_user_enabled = 1;
>   int __read_mostly watchdog_thresh = 10;
>   static int __read_mostly watchdog_hardlockup_available;
>