Return-path: Received: from perches-mx.perches.com ([206.117.179.246]:38226 "EHLO labridge.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756030Ab2GBVXU (ORCPT ); Mon, 2 Jul 2012 17:23:20 -0400 Message-ID: <1341264199.10162.2.camel@joe2Laptop> (sfid-20120702_232351_578752_9101C281) Subject: Re: [RFC][PATCH 1/2] lib: printf: append support of '%*p[Mm][FR]' From: Joe Perches To: Andy Shevchenko Cc: Andrew Morton , Andy Shevchenko , proski@gnu.org, Andrei Emeltchenko , linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Date: Mon, 02 Jul 2012 14:23:19 -0700 In-Reply-To: References: <20110930115306.3bc105cb@mj> <1340985513-15655-1-git-send-email-andriy.shevchenko@linux.intel.com> <1340986086.6562.36.camel@joe2Laptop> <20120629162649.f277177f.akpm@linux-foundation.org> <1341067733.10253.2.camel@joe2Laptop> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Mon, 2012-07-02 at 20:32 +0300, Andy Shevchenko wrote: > On Sat, Jun 30, 2012 at 5:48 PM, Joe Perches wrote: > > On Fri, 2012-06-29 at 16:26 -0700, Andrew Morton wrote: > >> On Fri, 29 Jun 2012 09:08:06 -0700 > >> Joe Perches wrote: > >> > >> > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > >> > [] > >> > > @@ -655,11 +655,12 @@ char *resource_string(char *buf, char *end, struct resource *res, > >> > > } > >> > > > >> > > static noinline_for_stack > >> > > -char *mac_address_string(char *buf, char *end, u8 *addr, > >> > > - struct printf_spec spec, const char *fmt) > >> > > +char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec, > >> > > + const char *fmt) > >> > > { > >> > > - char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")]; > >> > > - char *p = mac_addr; > >> > > + char hex_str[64*3]; /* support up to 64 bytes to print */ > >> > > >> > Might be too much stack though. > >> > >> Yes, it's a bit marginal, as this new capability might be used in debug > >> or crash situations where we're deep into the stack. The average case > >> could be improved by using alloca()-style allocation. > > > > Or maybe support larger sizes with a smaller > > stack buffer and a while loop. > > What do you think about mixed approach? Let's say we would use buffer > on stack for 8 bytes or less, and allocated buffer in case of larger > input. It allows to keep implementation simple. > I think the while loop is simplest. I'll code something up tomorrow unless you get to it first.