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authorOleg Nesterov <oleg@redhat.com>2015-09-05 01:48:13 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-05 02:54:41 +0300
commit9943242ca468149c4ce30d4633524c0866d4a87b (patch)
treea4ad8816368c646e29d299a12f2f4a06e87fe50c
parent1d3916869798755968b3cd764ab21f2bb86ffff7 (diff)
downloadlinux-9943242ca468149c4ce30d4633524c0866d4a87b.tar.xz
mremap: simplify the "overlap" check in mremap_to()
Minor, but this check is overcomplicated. Two half-intervals do NOT overlap if END1 <= START2 || END2 <= START1, mremap_to() just needs to negate this check. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Hugh Dickins <hughd@google.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mremap.c9
1 files changed, 2 insertions, 7 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index d3f42bece564..5a71cce8c6ea 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -407,13 +407,8 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len,
if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
goto out;
- /* Check if the location we're moving into overlaps the
- * old location at all, and fail if it does.
- */
- if ((new_addr <= addr) && (new_addr+new_len) > addr)
- goto out;
-
- if ((addr <= new_addr) && (addr+old_len) > new_addr)
+ /* Ensure the old/new locations do not overlap */
+ if (addr + old_len > new_addr && new_addr + new_len > addr)
goto out;
ret = do_munmap(mm, new_addr, new_len);