Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932241AbbFSVon (ORCPT ); Fri, 19 Jun 2015 17:44:43 -0400 Received: from g9t5008.houston.hp.com ([15.240.92.66]:47853 "EHLO g9t5008.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752960AbbFSVoc (ORCPT ); Fri, 19 Jun 2015 17:44:32 -0400 From: Toshi Kani To: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, akpm@linux-foundation.org Cc: travis@sgi.com, roland@purestorage.com, dan.j.williams@intel.com, x86@kernel.org, linux-nvdimm@ml01.01.org, linux-kernel@vger.kernel.org, Toshi Kani Subject: [PATCH 2/3] mm, x86: Remove region_is_ram() call from ioremap Date: Fri, 19 Jun 2015 15:44:04 -0600 Message-Id: <1434750245-6304-3-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1434750245-6304-1-git-send-email-toshi.kani@hp.com> References: <1434750245-6304-1-git-send-email-toshi.kani@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3175 Lines: 82 __ioremap_caller() calls region_is_ram() to look up the resource to check if a target range is RAM, which was added as an additinal check to improve the lookup performance over page_is_ram() (commit 906e36c5c717 "x86: use optimized ioresource lookup in ioremap function"). __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 functions walk through the resource table, there is no need to call the two functions. Furthermore, region_is_ram() has bugs and always returns with -1. This makes walk_system_ram_range() as the only check being used. Hence, remove the call to region_is_ram() from __ioremap_caller(). Note, removing the call to region_is_ram() is also necessary to fix the bugs in region_is_ram(). walk_system_ram_range() requires RAM ranges aligned by the page size in the resource table. e820_reserve_setup_data() updates the e820 table by allocating a separate entry to each data region in setup_data, which is not page-aligned. Therefore, walk_system_ram_range() is unable to detect the RAM ranges in setup_data. This restriction has allowed multiple uses of ioremap() to map setup_data. Using fixed region_is_ram() will cause these callers to start failing. After all ioremap to setup_data are converted, __ioremap_caller() may call region_is_ram() instead. Signed-off-by: Toshi Kani --- 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 56f8af7..928867e 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -89,7 +89,6 @@ 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; @@ -112,26 +111,15 @@ 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 0x%llx - 0x%llx\n", + WARN_ONCE(1, "ioremap on RAM at 0x%llx - 0x%llx\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 Please read the FAQ at http://www.tux.org/lkml/