These interfaces never did get used, so this commit removes them,
their rcutorture tests, and documentation referencing them.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NLai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

This commit applies a few updates based on a quick review of the RCU
documentations.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The list_for_each_continue_rcu() macro is no longer used, so this commit
removes it.  The list_for_each_entry_continue_rcu() macro should be
used instead.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The current documentation did not help someone grepping for SRCU to
learn that disabling preemption is not a replacement for srcu_read_lock(),
so upgrade the documentation to bring this out, not just for SRCU,
but also for RCU-bh.  Also document the fact that SRCU readers are
respected on CPUs executing in user mode, idle CPUs, and even on
offline CPUs.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Reviewed-by: NLai Jiangshan <laijs@cn.fujitsu.com>

The advent of call_srcu() and srcu_barrier() obsoleted some of the
documentation, so this commit brings that up to date.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The expedited RCU primitives can be quite useful, but they have some
high costs as well.  This commit updates and creates docbook comments
calling out the costs, and updates the RCU documentation as well.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Update various files in Documentation/RCU to reflect srcu_read_lock_raw()
and srcu_read_unlock_raw().  Credit to Peter Zijlstra for suggesting
use of the existing _raw suffix instead of the earlier bulkref names.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Add a section describing PROVE_RCU, DEBUG_OBJECTS_RCU_HEAD, and
the __rcu sparse checking to the RCU checklist.
Suggested-by: NDavid Miller <davem@davemloft.net>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

Update examples and lists of APIs to include these new
primitives.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: eric.dumazet@gmail.com
LKML-Reference: <1270852752-25278-3-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Adds a lockdep.txt file and updates checklist.txt and
whatisRCU.txt to reflect the new lockdep-enabled capabilities of
RCU.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-13-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add expedited functions.  Review documentation and update
obsolete verbiage.  Also fix the advice for the RCU CPU-stall
kernel configuration parameter, and document RCU CPU-stall
warnings.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12635142581866-git-send-email->
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch updates the rcutorture documentation to include
updated output format.  It also brings the RCU documentation up
to date.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: akpm@linux-foundation.org
Cc: torvalds@linux-foundation.org
Cc: davem@davemloft.net
Cc: dada1@cosmosbay.com
Cc: zbr@ioremap.net
Cc: jeff.chua.linux@gmail.com
Cc: paulus@samba.org
Cc: laijs@cn.fujitsu.com
Cc: jengelh@medozas.de
Cc: r000n@r000n.net
Cc: benh@kernel.crashing.org
Cc: mathieu.desnoyers@polymtl.ca
LKML-Reference: <12459460983193-git-send-email->
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Update the RCU documentation to call out the need for callers of
primitives like call_rcu() and synchronize_rcu() to prevent subsequent RCU
readers from hazard.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

All of the in-tree uses of list_for_each_rcu() have been converted to
list_for_each_entry_rcu(), so list_for_each_rcu() can now be removed.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Long-delayed update to the RCU documentation, including adding the new
call_rcu_sched() and rcu_barrier_sched() APIs.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Add an item to the RCU documentation checklist noting that RCU callbacks
can run in parallel.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Updated patch adding a variant of RCU that permits sleeping in read-side
critical sections.  SRCU is as follows:

o	Each use of SRCU creates its own srcu_struct, and each
	srcu_struct has its own set of grace periods.  This is
	critical, as it prevents one subsystem with a blocking
	reader from holding up SRCU grace periods for other
	subsystems.

o	The SRCU primitives (srcu_read_lock(), srcu_read_unlock(),
	and synchronize_srcu()) all take a pointer to a srcu_struct.

o	The SRCU primitives must be called from process context.

o	srcu_read_lock() returns an int that must be passed to
	the matching srcu_read_unlock().  Realtime RCU avoids the
	need for this by storing the state in the task struct,
	but SRCU needs to allow a given code path to pass through
	multiple SRCU domains -- storing state in the task struct
	would therefore require either arbitrary space in the
	task struct or arbitrary limits on SRCU nesting.  So I
	kicked the state-storage problem up to the caller.

	Of course, it is not permitted to call synchronize_srcu()
	while in an SRCU read-side critical section.

o	There is no call_srcu().  It would not be hard to implement
	one, but it seems like too easy a way to OOM the system.
	(Hey, we have enough trouble with call_rcu(), which does
	-not- permit readers to sleep!!!)  So, if you want it,
	please tell me why...

[josht@us.ibm.com: sparse notation]
Signed-off-by: NPaul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: NJosh Triplett <josh@freedesktop.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

An update to the RCU documentation calling out the
self-limiting-update-rate advantages of synchronize_rcu(), and describing
how to use call_rcu() in a way that results in self-limiting updates.
Self-limiting updates are important to avoiding RCU-induced OOM in face of
denial-of-service attacks.
Signed-off-by: NPaul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Updates to in-tree RCU documentation based on comments over the past few
months.
Signed-off-by: N"Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Update RCU documentation based on discussions and review of RCU-based tree
patches.  Add an introductory whatisRCU.txt file.

Signed-off-by: <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Update the RCU documentation to allow for the new synchronize_rcu() and
synchronize_sched() primitives.  Fix a few other nits as well.
Signed-off-by: NPaul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!