idr: make idr_get_next() good for rcu_read_lock()
idr: make idr_get_next() good for rcu_read_lock()

Make one small adjustment to idr_get_next(): take the height from the top
layer (stable under RCU) instead of from the root (unprotected by RCU), as
idr_find() does: so that it can be used with RCU locking.  Copied comment
on RCU locking from idr_find().

Signed-off-by: Hugh Dickins <d3abdf3e2800e6cb849f11b81e6eb50b34d96431@google.com>
Acked-by: KAMEZAWA Hiroyuki <634f508bd7c47cf0ee4126243675c3e598920fbc@jp.fujitsu.com>
Acked-by: Li Zefan <5dc16b054e85ffba6c8d314d8e55ae95dcab12a5@cn.fujitsu.com>
Cc: Eric Dumazet <a0baddf32b28d2f9429941ed4af2fe636e210591@gmail.com>
Acked-by: Tejun Heo <546b05909706652891a87f7bfe385ae147f61f91@kernel.org>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas