From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755851AbaAGIhn (ORCPT ); Tue, 7 Jan 2014 03:37:43 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:49656 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754551AbaAGIhm (ORCPT ); Tue, 7 Jan 2014 03:37:42 -0500 Date: Tue, 7 Jan 2014 09:37:40 +0100 From: Pavel Machek To: Joe Perches Cc: Tetsuo Handa , keescook@chromium.org, akpm@linux-foundation.org, geert@linux-m68k.org, jkosina@suse.cz, viro@zeniv.linux.org.uk, davem@davemloft.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH] lib/vsprintf: add %pT[C012] format specifier Message-ID: <20140107083740.GA5683@amd.pavel.ucw.cz> References: <201401041126.BHJ81291.VOHLOtMFOJFQFS@I-love.SAKURA.ne.jp> <201401051215.ACJ30759.MJSHtFFFVOOOQL@I-love.SAKURA.ne.jp> <1388945392.5808.19.camel@joe-AO722> <201401062300.GFE12908.FOQLFFJOSOMVHt@I-love.SAKURA.ne.jp> <1389029698.2433.3.camel@joe-AO722> <201401070641.HAC18733.VOFMFOLOJQSFHt@I-love.SAKURA.ne.jp> <1389047143.2433.14.camel@joe-AO722> <20140107001604.GD24243@amd.pavel.ucw.cz> <1389056635.2433.22.camel@joe-AO722> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389056635.2433.22.camel@joe-AO722> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 2014-01-06 17:03:55, Joe Perches wrote: > On Tue, 2014-01-07 at 01:16 +0100, Pavel Machek wrote: > > > > > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > > > > > [] > > > > > > @@ -1232,7 +1248,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, > > > > > > { > > > > > > int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0); > > > > > > > > > > > > - if (!ptr && *fmt != 'K') { > > > > > > + if (!ptr && *fmt != 'K' && *fmt != 'T') { > > > > > > > > > > I think this new 'T' comparison isn't necessary. > > > > > > > > This is needed for allowing comm_name() to accept NULL instead of current. > > > > > > Yeah, that's what I think isn't necessary. > > > > > > current is current_thread_info()->task. > > > > > > I think it's pretty lightweight in all arches and > > > it'd be simpler/more intelligible to not use NULL. > > > > > > Andrew? Any opinion? Anyone else? > > > > Andrew was worried about all the "current" duplication, IIRC. It is in > > the mail thread somewhere. And one condition in printk is price worth paying. > > Hi Pavel. > > I'm not nacking this, just stating my view. And I believe Andrew clearly stated his view, on the very topic you asked him on. > I believe I showed how many uses of vsprintf w/ current > there are. Passing NULL vs passing current as the %pT > argument is I think a negligible overall size delta too. One condition in if () is negligible, too, so passing NULL will still be overall win. And that was the point of this patch series. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html