Messages in this thread Patch in this message | | | Date | Thu, 2 Jul 2015 01:03:14 +0200 | From | Oleg Nesterov <> | Subject | [PATCH v2 5/5] mremap: simplify the "overlap" check in mremap_to() |
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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> --- mm/mremap.c | 9 ++------- 1 files changed, 2 insertions(+), 7 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c index d3f42be..5a71cce 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); -- 1.5.5.1
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