From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762962AbWLKRPl (ORCPT ); Mon, 11 Dec 2006 12:15:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762972AbWLKRPk (ORCPT ); Mon, 11 Dec 2006 12:15:40 -0500 Received: from an-out-0708.google.com ([209.85.132.247]:63445 "EHLO an-out-0708.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762962AbWLKRPj (ORCPT ); Mon, 11 Dec 2006 12:15:39 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:date:from:to:cc:subject:message-id:references:mime-version:content-type:content-disposition:in-reply-to:user-agent; b=ATHT5+IJyhawAcHUoTz0Xw4R87X6W1LyNdwLyhXyywtNk7OPVdRPH0Ii3/vPrtEfXNcPnt4e83qv7sCyvaySb6hIESAx4MKyDpMisfUyq8cnPhSRs5kjm6dLjnJa4TkGx0u5MAHToRFMr3+4a1j3wcO6NPmpMQ1/PQHfq9O2lVE= Date: Tue, 12 Dec 2006 02:15:31 +0900 From: Tejun Heo To: Jeff Garzik Cc: Arnd Bergmann , linux-ide@vger.kernel.org, linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH] libata: don't initialize sg in ata_exec_internal() if DMA_NONE (take #2) Message-ID: <20061211171531.GC18947@htj.dyndns.org> References: <200612081914.41810.arnd.bergmann@de.ibm.com> <20061211140258.GB18947@htj.dyndns.org> <457D7F5C.8040609@pobox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <457D7F5C.8040609@pobox.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Calling sg_init_one() with NULL buf causes oops on certain configurations. Don't initialize sg in ata_exec_internal() if DMA_NONE and make the function complain if @buf is NULL when dma_dir isn't DMA_NONE. While at it, fix comment. The problem is discovered and initial patch was submitted by Arnd Bergmann. Signed-off-by: Tejun Heo Cc: Arnd Bergmann --- Modified as suggested. Thanks. diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 011c0a8..0d51d13 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -1332,7 +1332,7 @@ unsigned ata_exec_internal_sg(struct ata_device *dev, } /** - * ata_exec_internal_sg - execute libata internal command + * ata_exec_internal - execute libata internal command * @dev: Device to which the command is sent * @tf: Taskfile registers for the command and the result * @cdb: CDB for packet command @@ -1353,11 +1353,17 @@ unsigned ata_exec_internal(struct ata_device *dev, struct ata_taskfile *tf, const u8 *cdb, int dma_dir, void *buf, unsigned int buflen) { - struct scatterlist sg; + struct scatterlist *psg = NULL, sg; + unsigned int n_elem = 0; - sg_init_one(&sg, buf, buflen); + if (dma_dir != DMA_NONE) { + WARN_ON(!buf); + sg_init_one(&sg, buf, buflen); + psg = &sg; + n_elem++; + } - return ata_exec_internal_sg(dev, tf, cdb, dma_dir, &sg, 1); + return ata_exec_internal_sg(dev, tf, cdb, dma_dir, psg, n_elem); } /**