X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Fmmap.c;h=6446c6134b04d8a8a10993e774b2bbe8bbcbd663;hb=92445eaaadc1f03f5a177ecc957bda76bf2ba8d5;hp=e6ee12344b139274325a1db834da1de6cf334da1;hpb=f1f76afd71e0f17af9a35fcb649f4bab53304a4d;p=linux-2.6

diff --git a/mm/mmap.c b/mm/mmap.c
index e6ee12344b..6446c6134b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1065,7 +1065,8 @@ munmap_back:
 	vma->vm_start = addr;
 	vma->vm_end = addr + len;
 	vma->vm_flags = vm_flags;
-	vma->vm_page_prot = protection_map[vm_flags & 0x0f];
+	vma->vm_page_prot = protection_map[vm_flags &
+				(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
 	vma->vm_pgoff = pgoff;
 
 	if (file) {
@@ -1089,6 +1090,12 @@ munmap_back:
 			goto free_vma;
 	}
 
+	/* Don't make the VMA automatically writable if it's shared, but the
+	 * backer wishes to know when pages are first written to */
+	if (vma->vm_ops && vma->vm_ops->page_mkwrite)
+		vma->vm_page_prot =
+			protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC)];
+
 	/* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
 	 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
 	 * that memory reservation must be checked; but that reservation
@@ -1921,7 +1928,8 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
 	vma->vm_end = addr + len;
 	vma->vm_pgoff = pgoff;
 	vma->vm_flags = flags;
-	vma->vm_page_prot = protection_map[flags & 0x0f];
+	vma->vm_page_prot = protection_map[flags &
+				(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
 	vma_link(mm, vma, prev, rb_link, rb_parent);
 out:
 	mm->total_vm += len >> PAGE_SHIFT;