x86: mm: restore original pte_special check

Mel Gorman · torvalds · commit c819f37e7e17 · 2015-02-12T18:54:08.000-08:00
Commit b38af47 ("x86,mm: fix pte_special versus pte_numa") adjusted the pte_special check to take into account that a special pte had SPECIAL and neither PRESENT nor PROTNONE. Now that NUMA hinting PTEs are no longer modifying _PAGE_PRESENT it should be safe to restore the original pte_special behaviour. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
@@ -132,13 +132,7 @@ static inline int pte_exec(pte_t pte)
 
 static inline int pte_special(pte_t pte)
 {
-	/*
-	 * See CONFIG_NUMA_BALANCING pte_numa in include/asm-generic/pgtable.h.
-	 * On x86 we have _PAGE_BIT_NUMA == _PAGE_BIT_GLOBAL+1 ==
-	 * __PAGE_BIT_SOFTW1 == _PAGE_BIT_SPECIAL.
-	 */
-	return (pte_flags(pte) & _PAGE_SPECIAL) &&
-		(pte_flags(pte) & (_PAGE_PRESENT|_PAGE_PROTNONE));
+	return pte_flags(pte) & _PAGE_SPECIAL;
 }
 
 static inline unsigned long pte_pfn(pte_t pte)

Original file line number	Diff line number	Diff line change
`@@ -132,13 +132,7 @@ static inline int pte_exec(pte_t pte)`
`132`	`132`
`133`	`133`	`static inline int pte_special(pte_t pte)`
`134`	`134`	`{`
`135`		`- /*`
`136`		`- * See CONFIG_NUMA_BALANCING pte_numa in include/asm-generic/pgtable.h.`
`137`		`- * On x86 we have _PAGE_BIT_NUMA == _PAGE_BIT_GLOBAL+1 ==`
`138`		`- * __PAGE_BIT_SOFTW1 == _PAGE_BIT_SPECIAL.`
`139`		`- */`
`140`		`- return (pte_flags(pte) & _PAGE_SPECIAL) &&`
`141`		`- (pte_flags(pte) & (_PAGE_PRESENT\|_PAGE_PROTNONE));`
	`135`	`+ return pte_flags(pte) & _PAGE_SPECIAL;`
`142`	`136`	`}`
`143`	`137`
`144`	`138`	`static inline unsigned long pte_pfn(pte_t pte)`