Return-path: Received: from mail-ee0-f46.google.com ([74.125.83.46]:63526 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752321Ab2GBRcs (ORCPT ); Mon, 2 Jul 2012 13:32:48 -0400 MIME-Version: 1.0 In-Reply-To: <1341067733.10253.2.camel@joe2Laptop> 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> Date: Mon, 2 Jul 2012 20:32:46 +0300 Message-ID: (sfid-20120702_193318_767318_1E3DB73A) Subject: Re: [RFC][PATCH 1/2] lib: printf: append support of '%*p[Mm][FR]' From: Andy Shevchenko To: Joe Perches Cc: Andrew Morton , Andy Shevchenko , proski@gnu.org, Andrei Emeltchenko , linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: 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. -- With Best Regards, Andy Shevchenko