Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754893AbbGYCn4 (ORCPT ); Fri, 24 Jul 2015 22:43:56 -0400 Received: from mga02.intel.com ([134.134.136.20]:57619 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754553AbbGYCnx (ORCPT ); Fri, 24 Jul 2015 22:43:53 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,542,1432623600"; d="scan'208";a="770837212" Subject: [PATCH v2 02/25] mm, x86: Remove region_is_ram() call from ioremap From: Dan Williams To: tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com Cc: linux-arch@vger.kernel.org, toshi.kani@hp.com, linux-nvdimm@ml01.01.org, "Luis R. Rodriguez" , linux-kernel@vger.kernel.org, Mike Travis , Roland Dreier , Ingo Molnar , Borislav Petkov , rmk+kernel@arm.linux.org.uk, hch@lst.de, linux-arm-kernel@lists.infradead.org Date: Fri, 24 Jul 2015 22:38:06 -0400 Message-ID: <20150725023806.8664.68687.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <20150725023649.8664.59145.stgit@dwillia2-desk3.amr.corp.intel.com> References: <20150725023649.8664.59145.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-8-g92dd MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3600 Lines: 94 From: Toshi Kani __ioremap_caller() calls region_is_ram() to walk through the iomem_resource table to check if a target range is in RAM, which was added to improve the lookup performance over page_is_ram() (commit 906e36c5c717 "x86: use optimized ioresource lookup in ioremap function"). page_is_ram() was no longer used when this change was added, though. __ioremap_caller() then calls walk_system_ram_range(), which had replaced page_is_ram() to improve the lookup performance (commit c81c8a1eeede "x86, ioremap: Speed up check for RAM pages"). Since both checks walk through the same iomem_resource table for the same purpose, there is no need to call the two functions. Furthermore, region_is_ram() always returns with -1, which makes walk_system_ram_range() as the only check being used at this point. Therefore, this patch changes __ioremap_caller() to call walk_system_ram_range() only. Note, removing the call to region_is_ram() is also necessary to fix bugs in region_is_ram(). walk_system_ram_range() requires RAM ranges be page-aligned in the iomem_resource table to work properly. This restriction has allowed multiple ioremaps to RAM (setup_data) which are page-unaligned. Using fixed region_is_ram() will cause these callers to start failing. After all ioremap callers to setup_data are converted, __ioremap_caller() may call region_is_ram() instead to remove this restriction. Signed-off-by: Toshi Kani Cc: Roland Dreier Cc: Mike Travis Cc: Luis R. Rodriguez Cc: Thomas Gleixner Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Borislav Petkov Signed-off-by: Dan Williams --- arch/x86/mm/ioremap.c | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-) diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index c13f7fdca142..12b1eaeab6b9 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -92,7 +92,6 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, pgprot_t prot; int retval; void __iomem *ret_addr; - int ram_region; /* Don't allow wraparound or zero size */ last_addr = phys_addr + size - 1; @@ -115,26 +114,15 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, /* * Don't allow anybody to remap normal RAM that we're using.. */ - /* First check if whole region can be identified as RAM or not */ - ram_region = region_is_ram(phys_addr, size); - if (ram_region > 0) { - WARN_ONCE(1, "ioremap on RAM at 0x%lx - 0x%lx\n", - (unsigned long int)phys_addr, - (unsigned long int)last_addr); - return NULL; - } - - /* If could not be identified(-1), check page by page */ - if (ram_region < 0) { - pfn = phys_addr >> PAGE_SHIFT; - last_pfn = last_addr >> PAGE_SHIFT; - if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL, + pfn = phys_addr >> PAGE_SHIFT; + last_pfn = last_addr >> PAGE_SHIFT; + if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL, __ioremap_check_ram) == 1) { - WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n", + WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n", &phys_addr, &last_addr); - return NULL; - } + return NULL; } + /* * Mappings have to be page-aligned */ -- 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/