mm/mremap: avoid unneeded do_munmap call

When old_len == new_len, do_munmap will return -EINVAL due to len == 0. 
This errno will be simply ignored because of old_len != new_len check.  So
it is unnecessary to call do_munmap when old_len == new_len because
nothing is actually done.

Link: https://lkml.kernel.org/r/20220401081023.37080-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Miaohe Lin 2022-04-28 23:16:14 -07:00 committed by akpm
parent f433195679
commit 3c9fe8b8f5

View File

@ -820,9 +820,9 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len,
goto out;
}
if (old_len >= new_len) {
if (old_len > new_len) {
ret = do_munmap(mm, addr+new_len, old_len - new_len, uf_unmap);
if (ret && old_len != new_len)
if (ret)
goto out;
old_len = new_len;
}