VM, x86, PAT: add a new vm flag to track full pfnmap at mmap

Impact: cleanup

Add a new vm flag VM_PFN_AT_MMAP to identify a PFNMAP that is
fully mapped with remap_pfn_range. Patch removes the overloading
of VM_INSERTPAGE from the earlier patch.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Nick Piggin <npiggin@suse.de>
LKML-Reference: <20090313233543.GA19909@linux-os.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/mm.h

@@ -98,12 +98,13 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */
 #define VM_NONLINEAR	0x00800000	/* Is non-linear (remap_file_pages) */
 #define VM_MAPPED_COPY	0x01000000	/* T if mapped copy of data (nommu mmap) */
-#define VM_INSERTPAGE	0x02000000	/* The vma has had "vm_insert_page()" done on it. Refer note in VM_PFNMAP_AT_MMAP below */
+#define VM_INSERTPAGE	0x02000000	/* The vma has had "vm_insert_page()" done on it */
 #define VM_ALWAYSDUMP	0x04000000	/* Always include in core dumps */
 
 #define VM_CAN_NONLINEAR 0x08000000	/* Has ->fault & does nonlinear pages */
 #define VM_MIXEDMAP	0x10000000	/* Can contain "struct page" and pure PFN pages */
 #define VM_SAO		0x20000000	/* Strong Access Ordering (powerpc) */
+#define VM_PFN_AT_MMAP	0x40000000	/* PFNMAP vma that is fully mapped at mmap time */
 
 #ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
@@ -126,17 +127,6 @@ extern unsigned int kobjsize(const void *objp);
  */
 #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
 
-/*
- * pfnmap vmas that are fully mapped at mmap time (not mapped on fault).
- * Used by x86 PAT to identify such PFNMAP mappings and optimize their handling.
- * Note VM_INSERTPAGE flag is overloaded here. i.e,
- * VM_INSERTPAGE && !VM_PFNMAP implies
- *     The vma has had "vm_insert_page()" done on it
- * VM_INSERTPAGE && VM_PFNMAP implies
- *     The vma is PFNMAP with full mapping at mmap time
- */
-#define VM_PFNMAP_AT_MMAP (VM_INSERTPAGE | VM_PFNMAP)
-
 /*
  * mapping from the currently active vm_flags protection bits (the
  * low four bits) to a page protection mask..
@@ -156,7 +146,7 @@ extern pgprot_t protection_map[16];
  */
 static inline int is_linear_pfn_mapping(struct vm_area_struct *vma)
 {
-	return ((vma->vm_flags & VM_PFNMAP_AT_MMAP) == VM_PFNMAP_AT_MMAP);
+	return (vma->vm_flags & VM_PFN_AT_MMAP);
 }
 
 static inline int is_pfn_mapping(struct vm_area_struct *vma)

mm/memory.c

@@ -1667,7 +1667,7 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
 	 */
 	if (addr == vma->vm_start && end == vma->vm_end) {
 		vma->vm_pgoff = pfn;
-		vma->vm_flags |= VM_PFNMAP_AT_MMAP;
+		vma->vm_flags |= VM_PFN_AT_MMAP;
 	} else if (is_cow_mapping(vma->vm_flags))
 		return -EINVAL;
 
@@ -1680,7 +1680,7 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
 		 * needed from higher level routine calling unmap_vmas
 		 */
 		vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
-		vma->vm_flags &= ~VM_PFNMAP_AT_MMAP;
+		vma->vm_flags &= ~VM_PFN_AT_MMAP;
 		return -EINVAL;
 	}