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Date:   Tue, 17 Sep 2019 09:02:54 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Petr Mladek <pmladek@suse.com>
Cc:     Daniel Vetter <daniel.vetter@ffwll.ch>,
        AndreaParri <parri.andrea@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Brendan Higgins <brendanhiggins@google.com>,
        Paul Turner <pjt@google.com>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Peter Zijlstra <peterz@infradead.org>,
        John Ogness <john.ogness@linutronix.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        LinusTorvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Theodore Ts'o <tytso@mit.edu>,
        PraritBhargava <prarit@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: printk meeting at LPC
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On Tue, 17 Sep 2019 09:52:16 +0200
Petr Mladek <pmladek@suse.com> wrote:

> Heh, I did some grepping and the return value is actually used on
> three locations:
> 
> $> git grep "= printk("  
> drivers/scsi/aic7xxx/aic79xx_core.c:	printed = printk("%s[0x%x]", name, value);
> drivers/scsi/aic7xxx/aic79xx_core.c:		printed += printk(" ");
> drivers/scsi/aic7xxx/aic79xx_core.c:			printed += printk("%s%s",
> drivers/scsi/aic7xxx/aic79xx_core.c:		printed += printk(") ");
> drivers/scsi/aic7xxx/aic79xx_core.c:		printed += printk(" ");
> drivers/scsi/aic7xxx/aic79xx_core.c:		cur_col = printk("\n%3d FIFO_USE[0x%x] ", SCB_GET_TAG(scb),
> drivers/scsi/aic7xxx/aic79xx_core.c:		cur_col += printk("SHADDR = 0x%x%x, SHCNT = 0x%x ",
> drivers/scsi/aic7xxx/aic79xx_core.c:		cur_col += printk("HADDR = 0x%x%x, HCNT = 0x%x ",
> drivers/scsi/aic7xxx/aic7xxx_core.c:	printed  = printk("%s[0x%x]", name, value);
> drivers/scsi/aic7xxx/aic7xxx_core.c:		printed += printk(" ");
> drivers/scsi/aic7xxx/aic7xxx_core.c:			printed += printk("%s%s",
> drivers/scsi/aic7xxx/aic7xxx_core.c:		printed += printk(") ");
> drivers/scsi/aic7xxx/aic7xxx_core.c:		printed += printk(" ");
> drivers/scsi/aic7xxx/aic7xxx_core.c:		cur_col  = printk("\n%3d ", i);
> drivers/scsi/aic7xxx/aic7xxx_core.c:		cur_col  = printk("\n%3d ", scb->hscb->tag);
> drivers/scsi/libsas/sas_ata.c:	r = printk("%s" SAS_FMT "ata%u: %s: %pV",
> kernel/locking/lockdep.c:			len += printk("%*s   %s", depth, "", usage_str[bit]);
> kernel/locking/lockdep.c:			len += printk(KERN_CONT " at:\n");
> 
> It is probably not a big deal. For example, lockdep uses the value
> just for formatting (extra spaces) when printing backtrace.
> 
> I agree that it does not make sense to return the value if it
> complicates the code too much. Well, we will need to count
> the string length also from another reason (reservation).

Well, it's being used. I was thinking of dropping it if it was not.
Let's keep it then.

Thanks for looking into this.

-- Steve