From mboxrd@z Thu Jan 1 00:00:00 1970 From: Finn Thain Subject: Re: [PATCH 00/12] scsi/NCR5380: fix debugging macros and #include structure Date: Wed, 19 Mar 2014 10:14:22 +1100 (EST) Message-ID: References: <20140318002822.372705594@telegraphics.com.au> <1395112756.20860.1.camel@joe-AO722> <1395146702.2812.47.camel@joe-AO722> <1395148051.2812.51.camel@joe-AO722> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from kvm5.telegraphics.com.au ([98.124.60.144]:38436 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758300AbaCRXOq (ORCPT ); Tue, 18 Mar 2014 19:14:46 -0400 In-Reply-To: <1395148051.2812.51.camel@joe-AO722> Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Joe Perches Cc: Geert Uytterhoeven , "James E.J. Bottomley" , scsi , Sam Creasey , Russell King , Michael Schmitz , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Linux/m68k On Tue, 18 Mar 2014, Joe Perches wrote: > On Tue, 2014-03-18 at 13:55 +0100, Geert Uytterhoeven wrote: > > > > #define dprintk(flg, fmt, ...) no_printk(fmt, ##__VA_ARGS__) > > Fine, but with a correction. > > no_printk keeps all side effects like performing any function calls made > by the statement or accessing any volatiles. > > Using > > do { if (0) no_printk(fmt, ##__VA_ARGS__); } while (0) > > does not have any side-effects. I take your point about having the compiler check arguments when NDEBUG & flg == 0. As for side-effects, chip register accesses would be affected if dprintk() expanded to no_printk() when NDEBUG & flg == 0. E.g. NCR5380.c line 1213: dprintk(NDEBUG_INTR, "scsi : unknown interrupt, BASR 0x%X, MR 0x%X, SR 0x%x\n", basr, NCR5380_read(MODE_REG), NCR5380_read(STATUS_REG)); I don't want to re-introduce side-effects into a dozen different NCR5380 drivers on three different architectures when I can test only one of those drivers. It's difficult to get good code coverage even for one driver. --