Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Dynamic tick (nohz) updates, perhaps most notably changes to force
     the tick on when needed due to lengthy in-kernel execution on CPUs
     on which RCU is waiting.

   - Linux-kernel memory consistency model updates.

   - Replace rcu_swap_protected() with rcu_prepace_pointer().

   - Torture-test updates.

   - Documentation updates.

   - Miscellaneous fixes"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
  security/safesetid: Replace rcu_swap_protected() with rcu_replace_pointer()
  net/sched: Replace rcu_swap_protected() with rcu_replace_pointer()
  net/netfilter: Replace rcu_swap_protected() with rcu_replace_pointer()
  net/core: Replace rcu_swap_protected() with rcu_replace_pointer()
  bpf/cgroup: Replace rcu_swap_protected() with rcu_replace_pointer()
  fs/afs: Replace rcu_swap_protected() with rcu_replace_pointer()
  drivers/scsi: Replace rcu_swap_protected() with rcu_replace_pointer()
  drm/i915: Replace rcu_swap_protected() with rcu_replace_pointer()
  x86/kvm/pmu: Replace rcu_swap_protected() with rcu_replace_pointer()
  rcu: Upgrade rcu_swap_protected() to rcu_replace_pointer()
  rcu: Suppress levelspread uninitialized messages
  rcu: Fix uninitialized variable in nocb_gp_wait()
  rcu: Update descriptions for rcu_future_grace_period tracepoint
  rcu: Update descriptions for rcu_nocb_wake tracepoint
  rcu: Remove obsolete descriptions for rcu_barrier tracepoint
  rcu: Ensure that ->rcu_urgent_qs is set before resched IPI
  workqueue: Convert for_each_wq to use built-in list check
  rcu: Several rcu_segcblist functions can be static
  rcu: Remove unused function hlist_bl_del_init_rcu()
  Documentation: Rename rcu_node_context_switch() to rcu_note_context_switch()
  ...

1 files changed, 11 insertions, 3 deletions

diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index 7e1a8721637a..58ba05c4d97f 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -290,7 +290,7 @@ rcu_dereference()
 	at any time, including immediately after the rcu_dereference().
 	And, again like rcu_assign_pointer(), rcu_dereference() is
 	typically used indirectly, via the _rcu list-manipulation
-	primitives, such as list_for_each_entry_rcu().
+	primitives, such as list_for_each_entry_rcu() [2].
 
 	[1] The variant rcu_dereference_protected() can be used outside
 	of an RCU read-side critical section as long as the usage is
@@ -302,9 +302,17 @@ rcu_dereference()
 	must prohibit.	The rcu_dereference_protected() variant takes
 	a lockdep expression to indicate which locks must be acquired
 	by the caller. If the indicated protection is not provided,
-	a lockdep splat is emitted.  See RCU/Design/Requirements/Requirements.html
+	a lockdep splat is emitted.  See Documentation/RCU/Design/Requirements/Requirements.rst
 	and the API's code comments for more details and example usage.
 
+	[2] If the list_for_each_entry_rcu() instance might be used by
+	update-side code as well as by RCU readers, then an additional
+	lockdep expression can be added to its list of arguments.
+	For example, given an additional "lock_is_held(&mylock)" argument,
+	the RCU lockdep code would complain only if this instance was
+	invoked outside of an RCU read-side critical section and without
+	the protection of mylock.
+
 The following diagram shows how each API communicates among the
 reader, updater, and reclaimer.
 
@@ -630,7 +638,7 @@ been able to write-acquire the lock otherwise.  The smp_mb__after_spinlock()
 promotes synchronize_rcu() to a full memory barrier in compliance with
 the "Memory-Barrier Guarantees" listed in:
 
-	Documentation/RCU/Design/Requirements/Requirements.html.
+	Documentation/RCU/Design/Requirements/Requirements.rst
 
 It is possible to nest rcu_read_lock(), since reader-writer locks may
 be recursively acquired.  Note also that rcu_read_lock() is immune