The patch titled
Subject: mremap: simplify the "overlap" check in mremap_to()
has been added to the -mm tree. Its filename is
mremap-simplify-the-overlap-check-in-mremap_to.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mremap-simplify-the-overlap-check-in-mremap_to.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mremap-simplify-the-overlap-check-in-mremap_to.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Benjamin LaHaise <bcrl@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff -puN mm/mremap.c~mremap-simplify-the-overlap-check-in-mremap_to mm/mremap.c
--- a/mm/mremap.c~mremap-simplify-the-overlap-check-in-mremap_to
+++ a/mm/mremap.c
@@ -407,13 +407,8 @@ static unsigned long mremap_to(unsigned
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);
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
mremap-dont-leak-new_vma-if-f_op-mremap-fails.patch
mm-move-mremap-from-file_operations-to-vm_operations_struct.patch
mremap-dont-do-mm_populatenew_addr-on-failure.patch
mremap-dont-do-uneccesary-checks-if-new_len-==-old_len.patch
mremap-simplify-the-overlap-check-in-mremap_to.patch
kmod-bunch-of-internal-functions-renames.patch
kmod-add-up-to-date-explanations-on-the-purpose-of-each-asynchronous-levels.patch
kmod-remove-unecessary-explicit-wide-cpu-affinity-setting.patch
linux-next.patch
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