From: Petr Mladek <pmladek@suse.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH v1] printk: Declare log_wait as external variable
Date: Tue, 11 Feb 2020 13:43:17 +0100 [thread overview]
Message-ID: <20200211124317.x5erhl7kvxj2nq6a@pathway.suse.cz> (raw)
In-Reply-To: <20200203131528.52825-1-andriy.shevchenko@linux.intel.com>
On Mon 2020-02-03 15:15:28, Andy Shevchenko wrote:
> Static analyzer is not happy:
>
> kernel/printk/printk.c:421:1: warning: symbol 'log_wait' was not declared. Should it be static?
>
> This is due to usage of log_wait in the other module without announcing
> its declaration to the world. I wasn't able to dug into deep history of
> reasons why it is so, and thus decide to make less invasive change, i.e.
> declaring log_wait as external variable to make static analyzer happy.
>
> Note the above is done if and only if the CONFIG_PROC_FS is enabled,
> otherwise we fallback to static variable.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> kernel/printk/printk.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 633f41a11d75..43b5cb88c607 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -418,7 +418,14 @@ DEFINE_RAW_SPINLOCK(logbuf_lock);
> } while (0)
>
> #ifdef CONFIG_PRINTK
> +
> +#ifdef CONFIG_PROC_FS
> +extern wait_queue_head_t log_wait; /* Used in fs/proc/kmsg.c */
> DECLARE_WAIT_QUEUE_HEAD(log_wait);
> +#else
> +static DECLARE_WAIT_QUEUE_HEAD(log_wait);
> +#endif /* CONFIG_PROC_FS */
This looks too complicated as a workaround for a warning.
I got really confused. Probably also because the macro DECLARE_*()
does a definition instead of a declaration.
As a minimal fix, I suggest to rename log_wait -> printk_log_wait
and declare it in include/linux/printk.h.
Even better solution might be to move fs/proc/kmsg.c to
kernel/printk/proc_kmsg.c and declare printk_log_wait only
in kernel/printk/internal.h. I think that this is what
Sergey suggested.
Another great thing would be to extract devkmsg stuff from
kernel/printk/printk.c and put it into kernel/printk/dev_kmsg.c.
I am not sure but it might help people to realize that there
are actually two different interfaces (old in /proc dmesg-like,
and in /dev new for systemd). Sigh.
I am not sure how deep and far you would like to go ;-)
Best Regards,
Petr
next prev parent reply other threads:[~2020-02-11 12:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 13:15 [PATCH v1] printk: Declare log_wait as external variable Andy Shevchenko
2020-02-04 2:16 ` Sergey Senozhatsky
2020-02-04 9:05 ` Andy Shevchenko
2020-02-04 11:22 ` Sergey Senozhatsky
2020-02-04 11:31 ` Andy Shevchenko
2020-02-11 12:43 ` Petr Mladek [this message]
2020-02-12 1:31 ` Sergey Senozhatsky
2020-02-12 14:03 ` Petr Mladek
2020-02-12 14:24 ` John Ogness
2020-02-13 12:02 ` Sergey Senozhatsky
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=20200211124317.x5erhl7kvxj2nq6a@pathway.suse.cz \
--to=pmladek@suse.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=sergey.senozhatsky@gmail.com \
/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).