Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262158AbVCISUD (ORCPT ); Wed, 9 Mar 2005 13:20:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262160AbVCISUD (ORCPT ); Wed, 9 Mar 2005 13:20:03 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:51586 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S262045AbVCISTn (ORCPT ); Wed, 9 Mar 2005 13:19:43 -0500 Subject: RE: [ANNOUNCE][PATCH 2.6.11 2/3] megaraid_sas: Announcing new mod ule for LSI Logic's SAS based MegaRAID controllers From: Arjan van de Ven To: "Bagalkote, Sreenivas" Cc: "'linux-kernel@vger.kernel.org'" , "'linux-scsi@vger.kernel.org'" , "'James Bottomley'" , "'Matt_Domsch@Dell.com'" , Andrew Morton , "'Christoph Hellwig'" In-Reply-To: <0E3FA95632D6D047BA649F95DAB60E570230CC20@exa-atlanta> References: <0E3FA95632D6D047BA649F95DAB60E570230CC20@exa-atlanta> Content-Type: text/plain Date: Wed, 09 Mar 2005 19:19:35 +0100 Message-Id: <1110392376.6280.139.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-3) Content-Transfer-Encoding: 7bit X-Spam-Score: 4.1 (++++) X-Spam-Report: SpamAssassin version 2.63 on pentafluge.infradead.org summary: Content analysis details: (4.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.3 RCVD_NUMERIC_HELO Received: contains a numeric HELO 1.1 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] 2.5 RCVD_IN_DYNABLOCK RBL: Sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 0.1 RCVD_IN_SORBS RBL: SORBS: sender is listed in SORBS [80.57.133.107 listed in dnsbl.sorbs.net] X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1459 Lines: 41 On Wed, 2005-03-09 at 12:44 -0500, Bagalkote, Sreenivas wrote: > >> > > >> >> . And since this is compile time > >> >> system-wide property, I kept it as driver global. > >> > > >> >that step I don't understand... why is it a global > >*VARIABLE* if it's > >> >compile time system-wide property... > >> > > >> > >> I see your point! Are you saying I should use > >if(sizeof(dma_addr_t)==8) > >> instead of the shortcut if(is_dma64)? > >yep > >well you can use a preprocessor define of something to make it slightly > >more readable (eg shortcut) if you want, but that's what I mean yeah.. > > > >gcc will optimize the entire unused code away this way, including the > >actual conditional jump, so for performance and bloat-ness > >point of view > >it's nice.... and of course generic design beauty ;) > > > > Great. Thanks! I will change it. If I understand you correctly, I should > #define IS_DMA64 (sizeof(dma_addr_t)==8). that's one way to do it yeah. > > Is this better than declaring is_dma64 global variable const? (Excuse the > oxymoron). in C yes; in C "const" doesn't quite mean what you want it to mean with this and as a result gcc I think can't optimize this the way it can with the define. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/