From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753426AbbIJHE6 (ORCPT ); Thu, 10 Sep 2015 03:04:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48543 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752927AbbIJHEz (ORCPT ); Thu, 10 Sep 2015 03:04:55 -0400 Subject: Re: [PATCH] lib/vsprintf.c: increase the size of the field_width variable To: Rasmus Villemoes , Joe Perches References: <1441793590-23856-1-git-send-email-mlombard@redhat.com> <1441816432.17219.57.camel@perches.com> <87mvwv4ea2.fsf@rasmusvillemoes.dk> Cc: akpm@linux-foundation.org, tj@kernel.org, linux-kernel@vger.kernel.org From: Maurizio Lombardi Message-ID: <55F12B94.30503@redhat.com> Date: Thu, 10 Sep 2015 09:04:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <87mvwv4ea2.fsf@rasmusvillemoes.dk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rasmus, On 09/09/2015 08:51 PM, Rasmus Villemoes wrote: > I'm also a little confused; I don't see what printk has to do with the > reported problem (I'd expect the /sys/... file to be generated by > something like seq_printf). In the scsi-debug case scnprintf is used, but it doesn't really matter because the change I made would influence printk and all its friends as well... everything that will parse "%*pb[l]". > >> %*pb is meant for smallish bitmaps, not big ones. > > Yup. And that leads to my other confusion: Given that the expected > output is given as "0-15", does the bitmap really consist of > S16_MAX > bits with only the first 16 set? > Yes. To be precise, in the example I mentioned in the commit message, a bitmap of size = 524288 bits is created. If you assign this number to a s16 variable the result will be zero and nothing will be printed. Joe, you mentioned that *pbl is meant for small bitmaps, what should I use with big ones? scsi-debug used the bitmap_scnlistprintf() function but since commit dbc760bcc150cc27160f0131b15db76350df4334 this function is just a wrapper around scnprintf("%*pbl"); as a consequence, the scsi-debug map_show() function stopped working correctly. Thanks, Maurizio Lombardi