From f34b439f34c49d7de858234bab5e2dd03cfaf3c1 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 15 Feb 2008 22:17:57 +0100 Subject: [PATCH] x86: CPA: avoid double checking of alias ranges When the CPA code is called with an virtual address in the range of the direct mapping or the high alias then we do not need to run through the alias check for this range. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/mm/pageattr.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index b8f53233151..3ee14996c82 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -594,19 +594,34 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias); static int cpa_process_alias(struct cpa_data *cpa) { struct cpa_data alias_cpa; - int ret; + int ret = 0; if (cpa->pfn > max_pfn_mapped) return 0; - alias_cpa = *cpa; - alias_cpa.vaddr = (unsigned long) __va(cpa->pfn << PAGE_SHIFT); + /* + * No need to redo, when the primary call touched the direct + * mapping already: + */ + if (!within(cpa->vaddr, PAGE_OFFSET, + PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT))) { - ret = __change_page_attr_set_clr(&alias_cpa, 0); + alias_cpa = *cpa; + alias_cpa.vaddr = (unsigned long) __va(cpa->pfn << PAGE_SHIFT); + + ret = __change_page_attr_set_clr(&alias_cpa, 0); + } #ifdef CONFIG_X86_64 if (ret) return ret; + /* + * No need to redo, when the primary call touched the high + * mapping already: + */ + if (within(cpa->vaddr, (unsigned long) _text, (unsigned long) _end)) + return 0; + /* * If the physical address is inside the kernel map, we need * to touch the high mapped kernel as well: -- 2.20.1