tree 2041a36a13bdd8b096dfbf52b63a87739ea97d6b
parent fd3e42fcc888a773572282575d2fdbf5cfd6216e
author Hugh Dickins <hugh@veritas.com> 1130634968 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1130647238 -0700

[PATCH] mm: dup_mmap down new mmap_sem

One anomaly remains from when Andrea rationalized the responsibilities of
mmap_sem and page_table_lock: in dup_mmap we add vmas to the child holding its
page_table_lock, but not the mmap_sem which normally guards the vma list and
rbtree.  Which could be an issue for unuse_mm: though since it just walks down
the list (today with page_table_lock, tomorrow not), it's probably okay.  Will
need a memory barrier?  Oh, keep it simple, Nick and I agreed, no harm in
taking child's mmap_sem here.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>