diff options
| author | James Bottomley <james.bottomley@steeleye.com> | 2003-09-03 20:13:28 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@home.osdl.org> | 2003-09-03 20:13:28 -0700 |
| commit | 31412915d5d1de833892ac14d61db02ec8dce625 (patch) | |
| tree | 4e71c6c3aa57a25dd9eadd3f4019ad8b609b3821 | |
| parent | ad425cf493fb719430154b5db87242ef3ea6c463 (diff) | |
[PATCH] fix remap of shared read only mappings
When mmap MAP_SHARED is done on a file, it gets marked with VM_MAYSHARE
and, if it's read/write, VM_SHARED. However, if it is remapped with
mremap(), the MAP_SHARED is only passed into the new mapping based on
VM_SHARED. This means that remapped read only MAP_SHARED mappings lose
VM_MAYSHARE. This is causing us a problem on parisc because we have to
align all shared mappings carefully to mitigate cache aliasing problems.
The fix is to key passing the MAP_SHARED flag back into the remapped are
off VM_MAYSHARE not VM_SHARED.
| -rw-r--r-- | mm/mremap.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index d9180f18ad6c..0412a204cb69 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -420,7 +420,7 @@ unsigned long do_mremap(unsigned long addr, if (flags & MREMAP_MAYMOVE) { if (!(flags & MREMAP_FIXED)) { unsigned long map_flags = 0; - if (vma->vm_flags & VM_SHARED) + if (vma->vm_flags & VM_MAYSHARE) map_flags |= MAP_SHARED; new_addr = get_unmapped_area(vma->vm_file, 0, new_len, |