linux-kernel - Re: [PATCH v2 1/3] libkmod: add a library notice log level print

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Date:   Thu, 23 Sep 2021 01:02:13 -0700
From:   Lucas De Marchi <lucas.demarchi@...el.com>
To:     Luis Chamberlain <mcgrof@...nel.org>
Cc:     Lucas De Marchi <lucas.de.marchi@...il.com>,
        linux-modules <linux-modules@...r.kernel.org>,
        live-patching@...r.kernel.org, fstests@...r.kernel.org,
        linux-block@...r.kernel.org, hare@...e.de, dgilbert@...erlog.com,
        Jessica Yu <jeyu@...nel.org>, osandov@...com,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/3] libkmod: add a library notice log level print

On Tue, Sep 21, 2021 at 11:40:52AM -0700, Luis Chamberlain wrote:
>On Mon, Sep 20, 2021 at 10:53:53PM -0700, Lucas De Marchi wrote:
>> On Mon, Aug 9, 2021 at 11:56 PM Luis Chamberlain <mcgrof@...nel.org> wrote:
>> >
>> > When you use pass the -v argument to modprobe we bump
>> > the log level from the default modprobe log level of
>> > LOG_WARNING (4) to LOG_NOTICE (5), however the library
>> > only has avaiable to print:
>> >
>> >  #define DBG(ctx, arg...) kmod_log_cond(ctx, LOG_DEBUG, ## arg)
>> >  #define INFO(ctx, arg...) kmod_log_cond(ctx, LOG_INFO, ## arg)
>> >  #define ERR(ctx, arg...) kmod_log_cond(ctx, LOG_ERR, ## arg)
>> >
>> > LOG_INFO (6) however is too high of a level for it to be
>> > effective at printing anything when modprobe -v is passed.
>> > And so the only way in which modprobe -v can trigger the
>> > library to print a verbose message is to use ERR() but that
>> > always prints something and we don't want that in some
>> > situations.
>> >
>> > We need to add a new log level macro which uses LOG_NOTICE (5)
>> > for a "normal but significant condition" which users and developers
>> > can use to look underneath the hood to confirm if a situation is
>> > happening.
>> >
>> > Signed-off-by: Luis Chamberlain <mcgrof@...nel.org>
>> > ---
>> >  libkmod/libkmod-internal.h | 2 ++
>> >  1 file changed, 2 insertions(+)
>> >
>> > diff --git a/libkmod/libkmod-internal.h b/libkmod/libkmod-internal.h
>> > index 398af9c..2e5e1bc 100644
>> > --- a/libkmod/libkmod-internal.h
>> > +++ b/libkmod/libkmod-internal.h
>> > @@ -25,10 +25,12 @@ static _always_inline_ _printf_format_(2, 3) void
>> >  #  else
>> >  #    define DBG(ctx, arg...) kmod_log_null(ctx, ## arg)
>> >  #  endif
>> > +#  define NOTICE(ctx, arg...) kmod_log_cond(ctx, LOG_NOTICE, ## arg)
>> >  #  define INFO(ctx, arg...) kmod_log_cond(ctx, LOG_INFO, ## arg)
>> >  #  define ERR(ctx, arg...) kmod_log_cond(ctx, LOG_ERR, ## arg)
>> >  #else
>> >  #  define DBG(ctx, arg...) kmod_log_null(ctx, ## arg)
>> > +#  define NOTICE(ctx, arg...) kmod_log_cond(ctx, LOG_NOTICE, ## arg)
>>
>> did you mean kmod_log_null()?
>
>Sure, feel free to change on your end or let me know if you would
>prefer if I respin.

fixed that and pushed this patch.

thanks
Lucas De Marchi

>
>  Luis