From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: linux-next: build warning after merge of the net tree Date: Wed, 07 Jul 2010 18:18:47 -0700 (PDT) Message-ID: <20100707.181847.62350965.davem@davemloft.net> References: <20100706142542.d723903f.sfr@canb.auug.org.au> <20100707.174522.148565561.davem@davemloft.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, joe@perches.com, gregkh@suse.de To: sfr@canb.auug.org.au Return-path: In-Reply-To: <20100707.174522.148565561.davem@davemloft.net> Sender: linux-next-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: David Miller Date: Wed, 07 Jul 2010 17:45:22 -0700 (PDT) > From: Stephen Rothwell > Date: Tue, 6 Jul 2010 14:25:42 +1000 > >> After merging the net tree, today's linux-next build (powerpc >> ppc64_defconfig) produced these warnings: >> >> drivers/scsi/sym53c8xx_2/sym_hipd.c: In function 'sym_print_msg': >> drivers/scsi/sym53c8xx_2/sym_hipd.c:78: warning: zero-length gnu_printf format string > > Thanks Stephen I'll look into this. Yeah this is a bit ugly. It used to be that the dev_*() format string was CPP pasted to whatever format string the user gave. So if the user gave an empty string it still looked like a non-empty printf string. But that no longer happens because we hide the implementation, and thus the top-level printf format string, in the external functions. It seems the construction: /* * Stupid hackaround for existing uses of non-printk uses dev_info * * Note that the definition of dev_info below is actually _dev_info * and a macro is used to avoid redefining dev_info */ #define dev_info(dev, fmt, arg...) _dev_info(dev, fmt, ##arg) added to linux/device.h was meant to handle these cases, but as we see it doesn't. It looks like there are just a hand-ful of cases, so maybe we can tweak them by hand. For example, in the sym53c8xx_2 driver bits we can replace the NULL labels passed to sym_print_msg() with a real string and therefore remove the "" case. Joe, any better ideas?