idr: fix overflow case for idr_for_each_entry_ul()
idr_for_each_entry_ul() is buggy as it can't handle overflow case correctly. When we have an ID == UINT_MAX, it becomes an infinite loop. This happens when running on 32-bit CPU where unsigned long has the same size with unsigned int. There is no better way to fix this than casting it to a larger integer, but we can't just 64 bit integer on 32 bit CPU. Instead we could just use an additional integer to help us to detect this overflow case, that is, adding a new parameter to this macro. Fortunately tc action is its only user right now. Fixes: 65a206c0 ("net/sched: Change act_api and act_xxx modules to use IDR") Reported-by: Li Shuang <shuali@redhat.com> Tested-by: Davide Caratti <dcaratti@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Chris Mi <chrism@mellanox.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>