mm: revert mremap pud_free anti-fix
Revert commit 1ecfd533f4c5 ("mm/mremap.c: call pud_free() after fail
calling pmd_alloc()").
The original code was correct: pud_alloc(), pmd_alloc(), pte_alloc_map()
ensure that the pud, pmd, pt is already allocated, and seldom do they
need to allocate; on failure, upper levels are freed if appropriate by
the subsequent do_munmap(). Whereas commit 1ecfd533f4c5 did an
unconditional pud_free() of a most-likely still-in-use pud: saved only
by the near-impossiblity of pmd_alloc() failing.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mremap.c b/mm/mremap.c
index 91b13d6..0843feb 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -25,7 +25,6 @@
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
-#include <asm/pgalloc.h>
#include "internal.h"
@@ -63,10 +62,8 @@
return NULL;
pmd = pmd_alloc(mm, pud, addr);
- if (!pmd) {
- pud_free(mm, pud);
+ if (!pmd)
return NULL;
- }
VM_BUG_ON(pmd_trans_huge(*pmd));