Merge branches 'doc.2019.01.26a', 'fixes.2019.01.26a', 'sil.2019.01.26a', 'spdx.2019...

doc.2019.01.26a:  Documentation updates.
fixes.2019.01.26a:  Miscellaneous fixes.
sil.2019.01.26a:  Removal of a few more spin_is_locked() instances.
spdx.2019.02.09a:  Add SPDX identifiers to RCU files
srcu.2019.01.26a:  SRCU updates.
torture.2019.01.26a: Torture-test updates.

diff --cc include/linux/rcupdate.h
Simple merge

diff --cc include/linux/srcu.h
Simple merge

diff --cc include/linux/srcutree.h
Simple merge

diff --cc include/linux/torture.h
Simple merge

diff --cc kernel/locking/locktorture.c
Simple merge

diff --cc kernel/rcu/rcu.h
Simple merge

diff --cc kernel/rcu/rcuperf.c
Simple merge

diff --cc kernel/rcu/rcutorture.c
Simple merge

diff --cc kernel/rcu/srcutree.c
Simple merge

diff --cc kernel/rcu/tiny.c
Simple merge

diff --cc kernel/rcu/tree.c
Simple merge

diff --cc kernel/rcu/tree.h
Simple merge

diff --cc kernel/rcu/tree_exp.h
Simple merge

diff --cc kernel/rcu/tree_plugin.h
Simple merge

diff --cc kernel/torture.c
Simple merge