From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262428AbUB0MZl (ORCPT ); Fri, 27 Feb 2004 07:25:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261813AbUB0MZl (ORCPT ); Fri, 27 Feb 2004 07:25:41 -0500 Received: from gate.crashing.org ([63.228.1.57]:48314 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S262614AbUB0MWb (ORCPT ); Fri, 27 Feb 2004 07:22:31 -0500 Subject: [PATCH] ppc64 iommu rewrite part 4/5 From: Benjamin Herrenschmidt To: Andrew Morton Cc: Linus Torvalds , Linux Kernel list Content-Type: text/plain Message-Id: <1077884018.22925.371.camel@gaston> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.5 Date: Fri, 27 Feb 2004 23:13:38 +1100 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Fix drivers/ide when using an IOMMU # This is a BitKeeper generated diff -Nru style patch. # # ChangeSet # 2004/02/27 22:28:18+11:00 benh@kernel.crashing.org # Make IDE advertise only 128 entries of SG table on archs with an IOMMU. # The current IOMMU implementations of pci_map_sg() may produce segments # that don't match the boundary requirements of IDE, thus causing the # driver to break them up. The BIO is supposed to account for that, # however, it cannot account for a pci_map_sg producing a segment of # the requested size, but with incorrect alignement, thus we may still # try to break up the list in more entries than is supported by the HW. # A similar fix already went in libata. The "real" long term fix will be # to move the boundary requirements to struct device so that pci_map_sg() # can respect them when producing the sglist. In the meantime, this # band-aid works around the problem. # # drivers/ide/ide-probe.c # 2004/02/27 22:28:06+11:00 benh@kernel.crashing.org +16 -1 # Make IDE advertise only 128 entries of SG table on archs with an IOMMU. # The current IOMMU implementations of pci_map_sg() may produce segments # that don't match the boundary requirements of IDE, thus causing the # driver to break them up. The BIO is supposed to account for that, # however, it cannot account for a pci_map_sg producing a segment of # the requested size, but with incorrect alignement, thus we may still # try to break up the list in more entries than is supported by the HW. # A similar fix already went in libata. The "real" long term fix will be # to move the boundary requirements to struct device so that pci_map_sg() # can respect them when producing the sglist. In the meantime, this # band-aid works around the problem. # diff -Nru a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c --- a/drivers/ide/ide-probe.c Fri Feb 27 22:44:36 2004 +++ b/drivers/ide/ide-probe.c Fri Feb 27 22:44:36 2004 @@ -50,6 +50,7 @@ #include #include #include +#include #include #include @@ -926,11 +927,25 @@ max_sectors = hwif->rqsize; blk_queue_max_sectors(q, max_sectors); - /* IDE DMA can do PRD_ENTRIES number of segments. */ +#if !defined(CONFIG_PCI) || PCI_DMA_BUS_IS_PHYS + /* IDE DMA can do PRD_ENTRIES number of segments. */ blk_queue_max_hw_segments(q, PRD_ENTRIES); /* This is a driver limit and could be eliminated. */ blk_queue_max_phys_segments(q, PRD_ENTRIES); +#else + /* When we have an IOMMU, we may have a problem where pci_map_sg() + * creates segments that don't completely match our boundary + * requirements and thus need to be broken up again. Because it + * doesn't align properly neither, we may actually have to break up + * to more segments than what was we got in the first place, a max + * worst case is twice as many. + * This will be fixed once we teach pci_map_sg() about our boundary + * requirements, hopefully soon + */ + blk_queue_max_hw_segments(q, PRD_ENTRIES / 2); + blk_queue_max_phys_segments(q, PRD_ENTRIES / 2); +#endif /* assign drive and gendisk queue */ drive->queue = q;