From 97f99fedf27f337e2d3d95ca01e321beb26edc3d Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Wed, 30 Jan 2008 13:33:55 +0100
Subject: [PATCH] x86: simplify 32-bit cpa largepage splitting
simplify 32-bit cpa largepage splitting: do a pure split and repeat
the pte lookup to get the new pte modified.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/mm/pageattr_32.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/pageattr_32.c b/arch/x86/mm/pageattr_32.c
index 570a37bf140..1011b21f8db 100644
--- a/arch/x86/mm/pageattr_32.c
+++ b/arch/x86/mm/pageattr_32.c
@@ -38,7 +38,7 @@ pte_t *lookup_address(unsigned long address, int *level)
}
static struct page *
-split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
+split_large_page(unsigned long address, pgprot_t ref_prot)
{
unsigned long addr;
struct page *base;
@@ -58,10 +58,9 @@ split_large_page(unsigned long address, pgprot_t prot, pgprot_t ref_prot)
pbase = (pte_t *)page_address(base);
paravirt_alloc_pt(&init_mm, page_to_pfn(base));
- for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
- set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT,
- addr == address ? prot : ref_prot));
- }
+ for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
+ set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT, ref_prot));
+
return base;
}
@@ -101,6 +100,7 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
BUG_ON(PageHighMem(page));
address = (unsigned long)page_address(page);
+repeat:
kpte = lookup_address(address, &level);
if (!kpte)
return -EINVAL;
@@ -128,7 +128,8 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
set_pte_atomic(kpte, mk_pte(page, prot));
} else {
struct page *split;
- split = split_large_page(address, prot, ref_prot);
+
+ split = split_large_page(address, ref_prot);
if (!split)
return -ENOMEM;
@@ -136,6 +137,7 @@ static int __change_page_attr(struct page *page, pgprot_t prot)
* There's a small window here to waste a bit of RAM:
*/
set_pmd_pte(kpte, address, mk_pte(split, ref_prot));
+ goto repeat;
}
return 0;
}
--
2.20.1