Re: [RFC PATCH 4/5] RCU: Add TASK_RCU_OFFSET

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Mon, Apr 11, 2011 at 11:08:14AM +0800, Lai Jiangshan wrote:
> On 04/08/2011 01:13 PM, Paul E. McKenney wrote:
> > On Fri, Apr 08, 2011 at 09:26:16AM +0800, Lai Jiangshan wrote:
> >> On 04/08/2011 12:26 AM, Paul E. McKenney wrote:
> >>> On Thu, Apr 07, 2011 at 08:47:37AM -0700, Paul E. McKenney wrote:
> >>>> On Thu, Apr 07, 2011 at 01:49:51PM +0800, Lai Jiangshan wrote:
> >>>>> On 04/07/2011 08:30 AM, Paul E. McKenney wrote:
> >>>>>> On Wed, Apr 06, 2011 at 02:27:39PM -0700, H. Peter Anvin wrote:
> >>>>>>> On 04/06/2011 02:06 PM, Peter Zijlstra wrote:
> >>>>>>>> On Wed, 2011-04-06 at 13:13 -0700, Paul E. McKenney wrote:
> >>>>>>>>> And the following patch builds correctly for defconfig x86 builds,
> >>>>>>>>> while allowing rcupdate.h to see the sched.h definitions as needed
> >>>>>>>>> to inline rcu_read_lock() and rcu_read_unlock().
> >>>>>>>>>
> >>>>>>>> Looks like an entirely reasonable patch to me ;-)
> >>>>>>>>
> >>>>>>>
> >>>>>>> Quite... a lot better than the original proposal!
> >>>>>>
> >>>>>> Glad you both like it!
> >>>>>>
> >>>>>> When I do an allyesconfig build, I do get errors during the "CHECK"
> >>>>>> phase, when it is putting things into the usr/include in the build tree.
> >>>>>> I believe that this is because I am exposing different header files to
> >>>>>> the library-export scripts.  The following patch silences some of them,
> >>>>>> but I am really out of my depth here.
> >>>>>>
> >>>>>> Sam, Jan, Michal, help?
> >>>>>>
> >>>>>> 							Thanx, Paul
> >>>>>>
> >>>>>> ------------------------------------------------------------------------
> >>>>>>
> >>>>>
> >>>>> Easy to split rcupdate.h, hard to resolve the dependence problem.
> >>>>>
> >>>>> You can apply the next additional patch when you test:
> >>>>
> >>>> I am sure that you are quite correct.  ;-)
> >>>>
> >>>> I am moving _rcu_read_lock() and _rcu_read_unlock() into
> >>>> include/linux/rcutree.h and include/linux/rcutiny.h, and I am sure that
> >>>> more pain will ensue.
> >>>>
> >>>> One thing I don't understand...  How does is it helping to group the
> >>>> task_struct RCU-related fields into a structure?  Is that generating
> >>>> better code on your platform due to smaller offsets or something?
> >>
> >> You don't like task_rcu_struct patch? I think it can make code clearer,
> >> and it can also check the code even when CONFIG_PREEMPT_RCU=n.
> >>
> >> For rcu_read_[un]lock(), it generates the same code, no better, no worse.
> >>
> >> It is just a cleanup patch, it is helpless for making rcu_read_[un]lock() inline,
> >> if you don't like it, I will give up it.
> > 
> > I don't know that I feel strongly either way about it.  It was necessary
> > with the integer-offset approach, but optional now.
> > 
> >>>> Also, does your patchset address the CHECK warnings?
> >>>
> >>> I take it back...  I applied the following patch on top of my earlier
> >>> one, and a defconfig x86 build completed without error.  (Though I have
> >>> not tested the results of the build.)
> >>>
> >>> One possible difference -- I did this work on top of a recent Linus
> >>> git commit (b2a8b4b81966) rather than on top of my -rcu tree.  Also,
> >>> I have not yet tried an allyesconfig build, which will no doubt locate
> >>> some more problems.
> >>>
> >>> 							Thanx, Paul
> >>>
> >>
> >> when defconfig or allyesconfig, CONFIG_PREEMPT=n and CONFIG_TREE_PREEMPT_RCU=n
> >> when you make them "y":
> >>
> >> In file included from include/linux/rcupdate.h:764:0,
> >>                  from include/linux/tracepoint.h:19,
> >>                  from include/linux/module.h:18,
> >>                  from include/linux/crypto.h:21,
> >>                  from arch/x86/kernel/asm-offsets.c:8:
> >> include/linux/rcutree.h:50:20: error: static declaration of ‘__rcu_read_lock’ follows non-static declaration
> >> include/linux/rcupdate.h:76:13: note: previous declaration of ‘__rcu_read_lock’ was here
> >> include/linux/rcutree.h:63:20: error: static declaration of ‘__rcu_read_unlock’ follows non-static declaration
> >> include/linux/rcupdate.h:77:13: note: previous declaration of ‘__rcu_read_unlock’ was here
> >> make[1]: *** [arch/x86/kernel/asm-offsets.s] Error 1
> >> make: *** [prepare0] Error 2
> > 
> > Yep.  I need to move the rcu_read_lock() APIs to follow the inclusion
> > of rcutree.h and rcutiny.h.  Also add include of sched.h to rcutiny.h.
> > The code movement does bloat the patch a bit.  But rcu_assign_pointer()
> > must precede the inclusion of rcutree.h and rcutiny.h, so it is not
> > possible to simply move the inclusions.  See below.
> > 
> > 							Thanx, Paul
> > 
> 
> sched.h still contains rcupdate.h after applied this patch.

Then we are not in sync -- sched.h does not include rcupdate.h in my tree.
It instead gets the struct rcu_head definition from include/linux/types.h.
See below for a consolidated patch.

							Thanx, Paul

> See my [PATCH 2/4] for more info.
> 
> 
> # make lib/is_single_threaded.o
>   CHK     include/linux/version.h
>   CHK     include/generated/utsrelease.h
>   CALL    scripts/checksyscalls.sh
>   CC      lib/is_single_threaded.o
> In file included from include/linux/rcupdate.h:639:0,
>                  from include/linux/rculist.h:10,
>                  from include/linux/sched.h:82,
>                  from lib/is_single_threaded.c:13:
> include/linux/rcutree.h: In function ‘__rcu_read_lock’:
> include/linux/rcutree.h:52:15: error: dereferencing pointer to incomplete type
> In file included from include/linux/rcupdate.h:639:0,
>                  from include/linux/rculist.h:10,
>                  from include/linux/sched.h:82,
>                  from lib/is_single_threaded.c:13:
> include/linux/rcutree.h: In function ‘__rcu_read_unlock’:
> include/linux/rcutree.h:68:5: error: dereferencing pointer to incomplete type
> include/linux/rcutree.h:70:7: error: dereferencing pointer to incomplete type
> include/linux/rcutree.h:71:46: error: dereferencing pointer to incomplete type
> include/linux/rcutree.h:71:78: error: dereferencing pointer to incomplete type
> include/linux/rcutree.h:71:6: warning: type defaults to ‘int’ in type name
> make[1]: *** [lib/is_single_threaded.o] Error 1
> make: *** [lib/is_single_threaded.o] Error 2

 drivers/scsi/scsi_sysctl.c |    1 +
 fs/proc/proc_sysctl.c      |    1 +
 include/linux/kernel.h     |    3 +++
 include/linux/pid.h        |    2 +-
 include/linux/rcupdate.h   |   29 +++++++++--------------------
 include/linux/rcutiny.h    |   35 +++++++++++++++++++++++++++++++++++
 include/linux/rcutree.h    |   37 +++++++++++++++++++++++++++++++++++++
 include/linux/sched.h      |   10 ++++------
 include/linux/sem.h        |    2 +-
 include/linux/soundcard.h  |    2 ++
 include/linux/sysctl.h     |    5 +++--
 include/linux/types.h      |   10 ++++++++++
 kernel/pid_namespace.c     |    2 ++
 kernel/rcutiny_plugin.h    |   38 ++------------------------------------
 kernel/rcutree_plugin.h    |   38 ++------------------------------------
 kernel/sysctl_binary.c     |    1 +
 kernel/sysctl_check.c      |    1 +
 net/core/sysctl_net_core.c |    1 +
 net/dccp/sysctl.c          |    1 +
 net/ipv6/sysctl_net_ipv6.c |    1 +
 net/irda/irsysctl.c        |    1 +
 net/phonet/sysctl.c        |    1 +
 net/rds/ib_sysctl.c        |    1 +
 net/rds/iw_sysctl.c        |    1 +
 net/rds/sysctl.c           |    1 +
 net/sctp/sysctl.c          |    1 +
 net/sunrpc/sysctl.c        |    1 +
 net/unix/sysctl_net_unix.c |    1 +
 net/xfrm/xfrm_sysctl.c     |    1 +
 29 files changed, 127 insertions(+), 102 deletions(-)

diff --git a/drivers/scsi/scsi_sysctl.c b/drivers/scsi/scsi_sysctl.c
index 2b6b93f..ecce1c6 100644
--- a/drivers/scsi/scsi_sysctl.c
+++ b/drivers/scsi/scsi_sysctl.c
@@ -6,6 +6,7 @@
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 
 #include "scsi_logging.h"
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index f50133c..180bf3e 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -2,6 +2,7 @@
  * /proc/sys support
  */
 #include <linux/init.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/proc_fs.h>
 #include <linux/security.h>
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 00cec4d..a243c13 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -648,6 +648,8 @@ struct sysinfo {
 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 
+#ifdef __KERNEL__
+
 /**
  * BUILD_BUG_ON - break compile if a condition is true.
  * @condition: the condition which the compiler should know is false.
@@ -673,6 +675,7 @@ extern int __build_bug_on_failed;
 		if (condition) __build_bug_on_failed = 1;	\
 	} while(0)
 #endif
+#endif /* __KERNEL__ */
 
 /* Trap pasters of __FUNCTION__ at compile-time */
 #define __FUNCTION__ (__func__)
diff --git a/include/linux/pid.h b/include/linux/pid.h
index efceda0..3c5719b 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -1,7 +1,7 @@
 #ifndef _LINUX_PID_H
 #define _LINUX_PID_H
 
-#include <linux/rcupdate.h>
+#include <linux/types.h>
 
 enum pid_type
 {
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index ff422d2..d009ebf 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -33,6 +33,7 @@
 #ifndef __LINUX_RCUPDATE_H
 #define __LINUX_RCUPDATE_H
 
+#include <linux/types.h>
 #include <linux/cache.h>
 #include <linux/spinlock.h>
 #include <linux/threads.h>
@@ -52,16 +53,6 @@ extern int rcutorture_runnable; /* for sysctl */
 #define ULONG_CMP_GE(a, b)	(ULONG_MAX / 2 >= (a) - (b))
 #define ULONG_CMP_LT(a, b)	(ULONG_MAX / 2 < (a) - (b))
 
-/**
- * struct rcu_head - callback structure for use with RCU
- * @next: next update requests in a list
- * @func: actual update function to call after the grace period.
- */
-struct rcu_head {
-	struct rcu_head *next;
-	void (*func)(struct rcu_head *head);
-};
-
 /* Exported common interfaces */
 extern void call_rcu_sched(struct rcu_head *head,
 			   void (*func)(struct rcu_head *rcu));
@@ -82,8 +73,6 @@ static inline void __rcu_read_unlock_bh(void)
 
 #ifdef CONFIG_PREEMPT_RCU
 
-extern void __rcu_read_lock(void);
-extern void __rcu_read_unlock(void);
 void synchronize_rcu(void);
 
 /*
@@ -141,14 +130,6 @@ static inline void rcu_exit_nohz(void)
 
 #endif /* #else #ifdef CONFIG_NO_HZ */
 
-#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
-#include <linux/rcutree.h>
-#elif defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU)
-#include <linux/rcutiny.h>
-#else
-#error "Unknown RCU implementation specified to kernel configuration"
-#endif
-
 /*
  * init_rcu_head_on_stack()/destroy_rcu_head_on_stack() are needed for dynamic
  * initialization and destruction of rcu_head on the stack. rcu_head structures
@@ -797,4 +778,12 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head)
 }
 #endif	/* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
 
+#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
+#include <linux/rcutree.h>
+#elif defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU)
+#include <linux/rcutiny.h>
+#else
+#error "Unknown RCU implementation specified to kernel configuration"
+#endif
+
 #endif /* __LINUX_RCUPDATE_H */
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 30ebd7c..167fb19 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -26,6 +26,7 @@
 #define __LINUX_TINY_H
 
 #include <linux/cache.h>
+#include <linux/sched.h>
 
 static inline void rcu_init(void)
 {
@@ -47,6 +48,40 @@ static inline void rcu_barrier(void)
 
 void rcu_barrier(void);
 void synchronize_rcu_expedited(void);
+void rcu_read_unlock_special(struct task_struct *t);
+
+/*
+ * Tiny-preemptible RCU implementation for rcu_read_lock().
+ * Just increment ->rcu_read_lock_nesting, shared state will be updated
+ * if we block.
+ */
+static inline void __rcu_read_lock(void)
+{
+	current->rcu_read_lock_nesting++;
+	barrier();
+}
+
+/*
+ * Tiny-preemptible RCU implementation for rcu_read_unlock().
+ * Decrement ->rcu_read_lock_nesting.  If the result is zero (outermost
+ * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then
+ * invoke rcu_read_unlock_special() to clean up after a context switch
+ * in an RCU read-side critical section and other special cases.
+ */
+static inline void __rcu_read_unlock(void)
+{
+	struct task_struct *t = current;
+
+	barrier();
+	--t->rcu_read_lock_nesting;
+	barrier();  /* decrement before load of ->rcu_read_unlock_special */
+	if (t->rcu_read_lock_nesting == 0 &&
+	    unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
+		rcu_read_unlock_special(t);
+#ifdef CONFIG_PROVE_LOCKING
+	WARN_ON_ONCE(t->rcu_read_lock_nesting < 0);
+#endif /* #ifdef CONFIG_PROVE_LOCKING */
+}
 
 #endif /* #else #ifdef CONFIG_TINY_RCU */
 
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 3a93348..012cc1c 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -30,6 +30,8 @@
 #ifndef __LINUX_RCUTREE_H
 #define __LINUX_RCUTREE_H
 
+#include <linux/sched.h>
+
 extern void rcu_init(void);
 extern void rcu_note_context_switch(int cpu);
 extern int rcu_needs_cpu(int cpu);
@@ -37,6 +39,41 @@ extern void rcu_cpu_stall_reset(void);
 
 #ifdef CONFIG_TREE_PREEMPT_RCU
 
+extern void rcu_read_unlock_special(struct task_struct *t);
+
+/*
+ * Tree-preemptable RCU implementation for rcu_read_lock().
+ * Just increment ->rcu_read_lock_nesting, shared state will be updated
+ * if we block.
+ */
+static inline void __rcu_read_lock(void)
+{
+	current->rcu_read_lock_nesting++;
+	barrier();
+}
+
+/*
+ * Tree-preemptable RCU implementation for rcu_read_unlock().
+ * Decrement ->rcu_read_lock_nesting.  If the result is zero (outermost
+ * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then
+ * invoke rcu_read_unlock_special() to clean up after a context switch
+ * in an RCU read-side critical section and other special cases.
+ */
+static inline void __rcu_read_unlock(void)
+{
+	struct task_struct *t = current;
+
+	barrier();
+	--t->rcu_read_lock_nesting;
+	barrier();  /* decrement before load of ->rcu_read_unlock_special */
+	if (t->rcu_read_lock_nesting == 0 &&
+	    unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
+		rcu_read_unlock_special(t);
+#ifdef CONFIG_PROVE_LOCKING
+	WARN_ON_ONCE(ACCESS_ONCE(t->rcu_read_lock_nesting) < 0);
+#endif /* #ifdef CONFIG_PROVE_LOCKING */
+}
+
 extern void exit_rcu(void);
 
 #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 83bd2e2..30a4444 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -78,7 +78,7 @@ struct sched_param {
 #include <linux/topology.h>
 #include <linux/proportions.h>
 #include <linux/seccomp.h>
-#include <linux/rcupdate.h>
+#include <linux/types.h>
 #include <linux/rculist.h>
 #include <linux/rtmutex.h>
 
@@ -2241,11 +2241,9 @@ int same_thread_group(struct task_struct *p1, struct task_struct *p2)
 	return p1->tgid == p2->tgid;
 }
 
-static inline struct task_struct *next_thread(const struct task_struct *p)
-{
-	return list_entry_rcu(p->thread_group.next,
-			      struct task_struct, thread_group);
-}
+/* Avoid #include hell for inlining rcu_read_lock(). */
+#define next_thread(p) \
+	list_entry_rcu((p)->thread_group.next, struct task_struct, thread_group)
 
 static inline int thread_group_empty(struct task_struct *p)
 {
diff --git a/include/linux/sem.h b/include/linux/sem.h
index f2961af..8489a1f 100644
--- a/include/linux/sem.h
+++ b/include/linux/sem.h
@@ -78,7 +78,7 @@ struct  seminfo {
 
 #ifdef __KERNEL__
 #include <asm/atomic.h>
-#include <linux/rcupdate.h>
+#include <linux/types.h>
 #include <linux/cache.h>
 
 struct task_struct;
diff --git a/include/linux/soundcard.h b/include/linux/soundcard.h
index 1904afe..f99c32f 100644
--- a/include/linux/soundcard.h
+++ b/include/linux/soundcard.h
@@ -1064,7 +1064,9 @@ typedef struct mixer_vol_table {
  */
 #define SEQ_DECLAREBUF()		SEQ_USE_EXTBUF()
 
+#ifdef __KERNEL__
 void seqbuf_dump(void);	/* This function must be provided by programs */
+#endif
 
 #define SEQ_PM_DEFINES int __foo_bar___
 
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 11684d9..be80a59 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -19,6 +19,8 @@
  ****************************************************************
  */
 
+#include <linux/key.h>
+
 #ifndef _LINUX_SYSCTL_H
 #define _LINUX_SYSCTL_H
 
@@ -1012,8 +1014,7 @@ extern int proc_do_large_bitmap(struct ctl_table *, int,
  */
 
 /* A sysctl table is an array of struct ctl_table: */
-struct ctl_table 
-{
+struct ctl_table {
 	const char *procname;		/* Text ID for /proc/sys, or zero */
 	void *data;
 	int maxlen;
diff --git a/include/linux/types.h b/include/linux/types.h
index 176da8c..868ef8b 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -231,6 +231,16 @@ struct hlist_node {
 	struct hlist_node *next, **pprev;
 };
 
+/**
+ * struct rcu_head - callback structure for use with RCU
+ * @next: next update requests in a list
+ * @func: actual update function to call after the grace period.
+ */
+struct rcu_head {
+	struct rcu_head *next;
+	void (*func)(struct rcu_head *head);
+};
+
 struct ustat {
 	__kernel_daddr_t	f_tfree;
 	__kernel_ino_t		f_tinode;
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index e9c9adc..bfa75df 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -8,6 +8,8 @@
  *
  */
 
+#include <linux/types.h>
+#include <asm/atomic.h>
 #include <linux/pid.h>
 #include <linux/pid_namespace.h>
 #include <linux/syscalls.h>
diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index 3cb8e36..d0e1ac3 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -520,23 +520,11 @@ void rcu_preempt_note_context_switch(void)
 }
 
 /*
- * Tiny-preemptible RCU implementation for rcu_read_lock().
- * Just increment ->rcu_read_lock_nesting, shared state will be updated
- * if we block.
- */
-void __rcu_read_lock(void)
-{
-	current->rcu_read_lock_nesting++;
-	barrier();  /* needed if we ever invoke rcu_read_lock in rcutiny.c */
-}
-EXPORT_SYMBOL_GPL(__rcu_read_lock);
-
-/*
  * Handle special cases during rcu_read_unlock(), such as needing to
  * notify RCU core processing or task having blocked during the RCU
  * read-side critical section.
  */
-static void rcu_read_unlock_special(struct task_struct *t)
+void rcu_read_unlock_special(struct task_struct *t)
 {
 	int empty;
 	int empty_exp;
@@ -616,29 +604,7 @@ static void rcu_read_unlock_special(struct task_struct *t)
 #endif /* #ifdef CONFIG_RCU_BOOST */
 	local_irq_restore(flags);
 }
-
-/*
- * Tiny-preemptible RCU implementation for rcu_read_unlock().
- * Decrement ->rcu_read_lock_nesting.  If the result is zero (outermost
- * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then
- * invoke rcu_read_unlock_special() to clean up after a context switch
- * in an RCU read-side critical section and other special cases.
- */
-void __rcu_read_unlock(void)
-{
-	struct task_struct *t = current;
-
-	barrier();  /* needed if we ever invoke rcu_read_unlock in rcutiny.c */
-	--t->rcu_read_lock_nesting;
-	barrier();  /* decrement before load of ->rcu_read_unlock_special */
-	if (t->rcu_read_lock_nesting == 0 &&
-	    unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
-		rcu_read_unlock_special(t);
-#ifdef CONFIG_PROVE_LOCKING
-	WARN_ON_ONCE(t->rcu_read_lock_nesting < 0);
-#endif /* #ifdef CONFIG_PROVE_LOCKING */
-}
-EXPORT_SYMBOL_GPL(__rcu_read_unlock);
+EXPORT_SYMBOL_GPL(rcu_read_unlock_special);
 
 /*
  * Check for a quiescent state from the current CPU.  When a task blocks,
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index a363871..4b27afd 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -196,18 +196,6 @@ static void rcu_preempt_note_context_switch(int cpu)
 }
 
 /*
- * Tree-preemptable RCU implementation for rcu_read_lock().
- * Just increment ->rcu_read_lock_nesting, shared state will be updated
- * if we block.
- */
-void __rcu_read_lock(void)
-{
-	current->rcu_read_lock_nesting++;
-	barrier();  /* needed if we ever invoke rcu_read_lock in rcutree.c */
-}
-EXPORT_SYMBOL_GPL(__rcu_read_lock);
-
-/*
  * Check for preempted RCU readers blocking the current grace period
  * for the specified rcu_node structure.  If the caller needs a reliable
  * answer, it must hold the rcu_node's ->lock.
@@ -261,7 +249,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags)
  * notify RCU core processing or task having blocked during the RCU
  * read-side critical section.
  */
-static void rcu_read_unlock_special(struct task_struct *t)
+void rcu_read_unlock_special(struct task_struct *t)
 {
 	int empty;
 	int empty_exp;
@@ -332,29 +320,7 @@ static void rcu_read_unlock_special(struct task_struct *t)
 		local_irq_restore(flags);
 	}
 }
-
-/*
- * Tree-preemptable RCU implementation for rcu_read_unlock().
- * Decrement ->rcu_read_lock_nesting.  If the result is zero (outermost
- * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then
- * invoke rcu_read_unlock_special() to clean up after a context switch
- * in an RCU read-side critical section and other special cases.
- */
-void __rcu_read_unlock(void)
-{
-	struct task_struct *t = current;
-
-	barrier();  /* needed if we ever invoke rcu_read_unlock in rcutree.c */
-	--t->rcu_read_lock_nesting;
-	barrier();  /* decrement before load of ->rcu_read_unlock_special */
-	if (t->rcu_read_lock_nesting == 0 &&
-	    unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
-		rcu_read_unlock_special(t);
-#ifdef CONFIG_PROVE_LOCKING
-	WARN_ON_ONCE(ACCESS_ONCE(t->rcu_read_lock_nesting) < 0);
-#endif /* #ifdef CONFIG_PROVE_LOCKING */
-}
-EXPORT_SYMBOL_GPL(__rcu_read_unlock);
+EXPORT_SYMBOL_GPL(rcu_read_unlock_special);
 
 #ifdef CONFIG_RCU_CPU_STALL_DETECTOR
 
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 3b8e028..58097b7 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1,4 +1,5 @@
 #include <linux/stat.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include "../fs/xfs/linux-2.6/xfs_sysctl.h"
 #include <linux/sunrpc/debug.h>
diff --git a/kernel/sysctl_check.c b/kernel/sysctl_check.c
index 4e4932a..a8a0df5 100644
--- a/kernel/sysctl_check.c
+++ b/kernel/sysctl_check.c
@@ -1,4 +1,5 @@
 #include <linux/stat.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include "../fs/xfs/linux-2.6/xfs_sysctl.h"
 #include <linux/sunrpc/debug.h>
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 385b609..528b975 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/mm.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/module.h>
 #include <linux/socket.h>
diff --git a/net/dccp/sysctl.c b/net/dccp/sysctl.c
index 4234882..bf609bc 100644
--- a/net/dccp/sysctl.c
+++ b/net/dccp/sysctl.c
@@ -10,6 +10,7 @@
  */
 
 #include <linux/mm.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include "dccp.h"
 #include "feat.h"
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 6dcf5e7..97a3ce0 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/mm.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/in6.h>
 #include <linux/ipv6.h>
diff --git a/net/irda/irsysctl.c b/net/irda/irsysctl.c
index d0b70da..11aaf12 100644
--- a/net/irda/irsysctl.c
+++ b/net/irda/irsysctl.c
@@ -25,6 +25,7 @@
 
 #include <linux/mm.h>
 #include <linux/ctype.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/init.h>
 
diff --git a/net/phonet/sysctl.c b/net/phonet/sysctl.c
index cea1c7d..2c2d479 100644
--- a/net/phonet/sysctl.c
+++ b/net/phonet/sysctl.c
@@ -23,6 +23,7 @@
  */
 
 #include <linux/seqlock.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/errno.h>
 #include <linux/init.h>
diff --git a/net/rds/ib_sysctl.c b/net/rds/ib_sysctl.c
index 1253b00..2f9a1a7 100644
--- a/net/rds/ib_sysctl.c
+++ b/net/rds/ib_sysctl.c
@@ -31,6 +31,7 @@
  *
  */
 #include <linux/kernel.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/proc_fs.h>
 
diff --git a/net/rds/iw_sysctl.c b/net/rds/iw_sysctl.c
index e2e4717..8c4051b 100644
--- a/net/rds/iw_sysctl.c
+++ b/net/rds/iw_sysctl.c
@@ -31,6 +31,7 @@
  *
  */
 #include <linux/kernel.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/proc_fs.h>
 
diff --git a/net/rds/sysctl.c b/net/rds/sysctl.c
index 25ad0c7..46d2d1d 100644
--- a/net/rds/sysctl.c
+++ b/net/rds/sysctl.c
@@ -31,6 +31,7 @@
  *
  */
 #include <linux/kernel.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/proc_fs.h>
 
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 50cb57f..c2903ce 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -43,6 +43,7 @@
 
 #include <net/sctp/structs.h>
 #include <net/sctp/sctp.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 
 static int zero = 0;
diff --git a/net/sunrpc/sysctl.c b/net/sunrpc/sysctl.c
index e65dcc6..1429601 100644
--- a/net/sunrpc/sysctl.c
+++ b/net/sunrpc/sysctl.c
@@ -11,6 +11,7 @@
 #include <linux/linkage.h>
 #include <linux/ctype.h>
 #include <linux/fs.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/module.h>
 
diff --git a/net/unix/sysctl_net_unix.c b/net/unix/sysctl_net_unix.c
index 397cffe..6d2766e 100644
--- a/net/unix/sysctl_net_unix.c
+++ b/net/unix/sysctl_net_unix.c
@@ -11,6 +11,7 @@
 
 #include <linux/mm.h>
 #include <linux/slab.h>
+#include <linux/key.h>
 #include <linux/sysctl.h>
 
 #include <net/af_unix.h>
diff --git a/net/xfrm/xfrm_sysctl.c b/net/xfrm/xfrm_sysctl.c
index 05640bc..a50e4bf 100644
--- a/net/xfrm/xfrm_sysctl.c
+++ b/net/xfrm/xfrm_sysctl.c
@@ -1,3 +1,4 @@
+#include <linux/key.h>
 #include <linux/sysctl.h>
 #include <linux/slab.h>
 #include <net/net_namespace.h>