From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751298AbVHQVeu (ORCPT ); Wed, 17 Aug 2005 17:34:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751299AbVHQVeu (ORCPT ); Wed, 17 Aug 2005 17:34:50 -0400 Received: from gate.crashing.org ([63.228.1.57]:38348 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S1751298AbVHQVet (ORCPT ); Wed, 17 Aug 2005 17:34:49 -0400 Subject: [PATCH] ppc64: iommu vmerge fix] From: Benjamin Herrenschmidt To: Andrew Morton Cc: Linux Kernel list , Linus Torvalds Content-Type: text/plain Date: Thu, 18 Aug 2005 07:32:18 +1000 Message-Id: <1124314339.8849.32.camel@gaston> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Brian King (Looks quite bad, should probably get in right away) The patch below fixes a bug in the PPC64 iommu vmerge code which results in the potential for iommu_unmap_sg to go off unmapping more than it should. This was found on a test system which resulted in PCI bus errors due to PCI memory being unmapped while DMAs were still in progress. Signed-off-by: Brian King Signed-off-by: Benjamin Herrenschmidt --- linux-2.6-bjking1/arch/ppc64/kernel/iommu.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff -puN arch/ppc64/kernel/iommu.c~ppc64_iommu_vmerge_fix arch/ppc64/kernel/iommu.c --- linux-2.6/arch/ppc64/kernel/iommu.c~ppc64_iommu_vmerge_fix 2005-08-17 15:34:50.000000000 -0500 +++ linux-2.6-bjking1/arch/ppc64/kernel/iommu.c 2005-08-17 15:35:19.000000000 -0500 @@ -242,7 +242,7 @@ int iommu_map_sg(struct device *dev, str dma_addr_t dma_next = 0, dma_addr; unsigned long flags; struct scatterlist *s, *outs, *segstart; - int outcount; + int outcount, incount; unsigned long handle; BUG_ON(direction == DMA_NONE); @@ -252,6 +252,7 @@ int iommu_map_sg(struct device *dev, str outs = s = segstart = &sglist[0]; outcount = 1; + incount = nelems; handle = 0; /* Init first segment length for backout at failure */ @@ -338,10 +339,10 @@ int iommu_map_sg(struct device *dev, str DBG("mapped %d elements:\n", outcount); - /* For the sake of iommu_free_sg, we clear out the length in the + /* For the sake of iommu_unmap_sg, we clear out the length in the * next entry of the sglist if we didn't fill the list completely */ - if (outcount < nelems) { + if (outcount < incount) { outs++; outs->dma_address = DMA_ERROR_CODE; outs->dma_length = 0; _