Use VM_ flags in protection_map rather than magic value

PATCH In review Matt Helsley 2 participants 2 messages Nov 6, 2007 – Nov 7, 2007

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Memory management Memory mapping

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Matt Helsley

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2007-11-06 22:27 UTC #0 lore raw

PATCH 1/1 Use VM_ flags in protection_map rather than magic value

Replace the magic value with a mask of flags that produce the same value. This is consistent with the other uses of protection_map[].

Signed-off-by Matt Helsley <[email protected]>

---
 mm/mmap.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

mm/mmap.c +2 -1

Index: linux-2.6.23/mm/mmap.c
===================================================================
@@ -2245,11 +2245,12 @@ int install_special_mapping(struct mm_st
 	vma->vm_mm = mm;
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;
 
 	vma->vm_flags = vm_flags | mm->def_flags;
-	vma->vm_page_prot = protection_map[vma->vm_flags & 7];
+	vma->vm_page_prot = protection_map[vma->vm_flags &
+						(VM_READ|VM_WRITE|VM_EXEC)];
 
 	vma->vm_ops = &special_mapping_vmops;
 	vma->vm_private_data = pages;
 
 	if (unlikely(insert_vm_struct(mm, vma))) {

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Hugh Dickins

2007-11-07 17:30 UTC #1 lore raw

Quoted 4 lines · Matt Helsley

Replace the magic value with a mask of flags that produce the same value. This is consistent with the other uses of protection_map[].
Signed-off-by Matt Helsley <[email protected]>

Thanks, but this comes just a little too late: see 2.6.24-rc1 or -rc2. Hugh

Quoted 12 lines

---
 mm/mmap.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-2.6.23/mm/mmap.c
===================================================================
mm/mmap.c +0 -0
@@ -2245,11 +2245,12 @@ int install_special_mapping(struct mm_st
 	vma->vm_mm = mm;
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;

mm/mmap.c int install_special_mapping(struct mm_st · line 2256

Quoted 10 lines

mm/mmap.c +2 -1

 
 	vma->vm_flags = vm_flags | mm->def_flags;
-	vma->vm_page_prot = protection_map[vma->vm_flags & 7];
+	vma->vm_page_prot = protection_map[vma->vm_flags &
+						(VM_READ|VM_WRITE|VM_EXEC)];
 
 	vma->vm_ops = &special_mapping_vmops;
 	vma->vm_private_data = pages;
 
 	if (unlikely(insert_vm_struct(mm, vma))) {