Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763858AbXHLAbA (ORCPT ); Sat, 11 Aug 2007 20:31:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758018AbXHLAas (ORCPT ); Sat, 11 Aug 2007 20:30:48 -0400 Received: from ug-out-1314.google.com ([66.249.92.169]:64278 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751506AbXHLAaq (ORCPT ); Sat, 11 Aug 2007 20:30:46 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:from:to:subject:date:user-agent:cc:mime-version:content-type:content-transfer-encoding:content-disposition:message-id; b=rQWvV1xlrjBUXidNejgzPNSsv/A3EFC/PRFFVS7PPqzrN3e3KsvFIcL+Z9Co44Zdt3MNC0O8Shn4EdPgjSoCrPgfq4fmriGfqBDU7dD4gv3xXpCJj1JrT//a8qs7sn67wRyqaCNtFd895p26eIPeabNrrF+hoH1whG/99vDOWts= From: Jesper Juhl To: linux-scsi@vger.kernel.org Subject: cciss: warning: right shift count >= width of type Date: Sun, 12 Aug 2007 02:28:26 +0200 User-Agent: KMail/1.9.7 Cc: Linux Kernel Mailing List , Jesper Juhl MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200708120228.26234.jesper.juhl@gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1597 Lines: 54 Hi, I've been building some randconfig kernels lately and I've noticed this in a few builds : drivers/block/cciss.c:2614: warning: right shift count >= width of type drivers/block/cciss.c:2615: warning: right shift count >= width of type drivers/block/cciss.c:2616: warning: right shift count >= width of type The code in question is this : static void do_cciss_request(struct request_queue *q) { ... sector_t start_blk; ... c->Request.CDB[2]= (start_blk >> 56) & 0xff; //MSB c->Request.CDB[3]= (start_blk >> 48) & 0xff; c->Request.CDB[4]= (start_blk >> 40) & 0xff; ... } The problem stems from these lines in include/linux/types.h : ... #ifdef CONFIG_LBD typedef u64 sector_t; #else typedef unsigned long sector_t; #endif ... So on a 32bit arch without CONFIG_LBD, sector_t is going to be 32 bits wide. Thus it seems gcc is absolutely right in complaining about those 56, 48 & 40 bit shifts, since they are indeed wider than the type in the "!CONFIG_LBD on a 32bit arch" case. I must admit that I have no idear what the proper way to deal with that is, so I'll just report it so hopefully someone else can fix it. By the way; I'm building current Linus git tree, head at commit ac07860264bd2b18834d3fa3be47032115524cea Kind regards, Jesper Juhl - 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/