2 files changed, 210 insertions, 119 deletions

diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h
new file mode 100644
index 000000000000..2b8b045a51d5
--- /dev/null
+++ b/include/linux/rcuclassic.h
@@ -0,0 +1,161 @@
+/*
+ * Read-Copy Update mechanism for mutual exclusion (classic version)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright IBM Corporation, 2001
+ *
+ * Author: Dipankar Sarma <dipankar@in.ibm.com>
+ *
+ * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
+ * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
+ * Papers:
+ * http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf
+ * http://lse.sourceforge.net/locking/rclock_OLS.2001.05.01c.sc.pdf (OLS2001)
+ *
+ * For detailed explanation of Read-Copy Update mechanism see -
+ *              Documentation/RCU
+ *
+ */
+
+#ifndef __LINUX_RCUCLASSIC_H
+#define __LINUX_RCUCLASSIC_H
+
+#ifdef __KERNEL__
+
+#include <linux/cache.h>
+#include <linux/spinlock.h>
+#include <linux/threads.h>
+#include <linux/percpu.h>
+#include <linux/cpumask.h>
+#include <linux/seqlock.h>
+
+
+/* Global control variables for rcupdate callback mechanism. */
+struct rcu_ctrlblk {
+        long    cur;            /* Current batch number.                      */
+        long    completed;      /* Number of the last completed batch         */
+        int     next_pending;   /* Is the next batch already waiting?         */
+
+        int     signaled;
+
+        spinlock_t      lock    ____cacheline_internodealigned_in_smp;
+        cpumask_t       cpumask; /* CPUs that need to switch in order    */
+                                 /* for current batch to proceed.        */
+} ____cacheline_internodealigned_in_smp;
+
+/* Is batch a before batch b ? */
+static inline int rcu_batch_before(long a, long b)
+{
+        return (a - b) < 0;
+}
+
+/* Is batch a after batch b ? */
+static inline int rcu_batch_after(long a, long b)
+{
+        return (a - b) > 0;
+}
+
+/*
+ * Per-CPU data for Read-Copy UPdate.
+ * nxtlist - new callbacks are added here
+ * curlist - current batch for which quiescent cycle started if any
+ */
+struct rcu_data {
+        /* 1) quiescent state handling : */
+        long            quiescbatch;     /* Batch # for grace period */
+        int             passed_quiesc;   /* User-mode/idle loop etc. */
+        int             qs_pending;      /* core waits for quiesc state */
+
+        /* 2) batch handling */
+        long            batch;           /* Batch # for current RCU batch */
+        struct rcu_head *nxtlist;
+        struct rcu_head **nxttail;
+        long            qlen;            /* # of queued callbacks */
+        struct rcu_head *curlist;
+        struct rcu_head **curtail;
+        struct rcu_head *donelist;
+        struct rcu_head **donetail;
+        long            blimit;          /* Upper limit on a processed batch */
+        int cpu;
+        struct rcu_head barrier;
+};
+
+DECLARE_PER_CPU(struct rcu_data, rcu_data);
+DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
+
+/*
+ * Increment the quiescent state counter.
+ * The counter is a bit degenerated: We do not need to know
+ * how many quiescent states passed, just if there was at least
+ * one since the start of the grace period. Thus just a flag.
+ */
+static inline void rcu_qsctr_inc(int cpu)
+{
+        struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+        rdp->passed_quiesc = 1;
+}
+static inline void rcu_bh_qsctr_inc(int cpu)
+{
+        struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
+        rdp->passed_quiesc = 1;
+}
+
+extern int rcu_pending(int cpu);
+extern int rcu_needs_cpu(int cpu);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+extern struct lockdep_map rcu_lock_map;
+# define rcu_read_acquire()     \
+                        lock_acquire(&rcu_lock_map, 0, 0, 2, 1, _THIS_IP_)
+# define rcu_read_release()     lock_release(&rcu_lock_map, 1, _THIS_IP_)
+#else
+# define rcu_read_acquire()     do { } while (0)
+# define rcu_read_release()     do { } while (0)
+#endif
+
+#define __rcu_read_lock() \
+        do { \
+                preempt_disable(); \
+                __acquire(RCU); \
+                rcu_read_acquire(); \
+        } while (0)
+#define __rcu_read_unlock() \
+        do { \
+                rcu_read_release(); \
+                __release(RCU); \
+                preempt_enable(); \
+        } while (0)
+#define __rcu_read_lock_bh() \
+        do { \
+                local_bh_disable(); \
+                __acquire(RCU_BH); \
+                rcu_read_acquire(); \
+        } while (0)
+#define __rcu_read_unlock_bh() \
+        do { \
+                rcu_read_release(); \
+                __release(RCU_BH); \
+                local_bh_enable(); \
+        } while (0)
+
+#define __synchronize_sched() synchronize_rcu()
+
+extern void __rcu_init(void);
+extern void rcu_check_callbacks(int cpu, int user);
+extern void rcu_restart_cpu(int cpu);
+
+#endif /* __KERNEL__ */
+#endif /* __LINUX_RCUCLASSIC_H */
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index cc24a01df940..12aa13e13150 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -15,7 +15,7 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  *
- * Copyright (C) IBM Corporation, 2001
+ * Copyright IBM Corporation, 2001
  *
  * Author: Dipankar Sarma <dipankar@in.ibm.com>
  * 
@@ -53,96 +53,14 @@ struct rcu_head {
         void (*func)(struct rcu_head *head);
 };
 
+#include <linux/rcuclassic.h>
+
 #define RCU_HEAD_INIT   { .next = NULL, .func = NULL }
 #define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT
 #define INIT_RCU_HEAD(ptr) do { \
        (ptr)->next = NULL; (ptr)->func = NULL; \
 } while (0)
 
-
-
-/* Global control variables for rcupdate callback mechanism. */
-struct rcu_ctrlblk {
-        long    cur;            /* Current batch number.                      */
-        long    completed;      /* Number of the last completed batch         */
-        int     next_pending;   /* Is the next batch already waiting?         */
-
-        int     signaled;
-
-        spinlock_t      lock    ____cacheline_internodealigned_in_smp;
-        cpumask_t       cpumask; /* CPUs that need to switch in order    */
-                                 /* for current batch to proceed.        */
-} ____cacheline_internodealigned_in_smp;
-
-/* Is batch a before batch b ? */
-static inline int rcu_batch_before(long a, long b)
-{
-        return (a - b) < 0;
-}
-
-/* Is batch a after batch b ? */
-static inline int rcu_batch_after(long a, long b)
-{
-        return (a - b) > 0;
-}
-
-/*
- * Per-CPU data for Read-Copy UPdate.
- * nxtlist - new callbacks are added here
- * curlist - current batch for which quiescent cycle started if any
- */
-struct rcu_data {
-        /* 1) quiescent state handling : */
-        long            quiescbatch;     /* Batch # for grace period */
-        int             passed_quiesc;   /* User-mode/idle loop etc. */
-        int             qs_pending;      /* core waits for quiesc state */
-
-        /* 2) batch handling */
-        long            batch;           /* Batch # for current RCU batch */
-        struct rcu_head *nxtlist;
-        struct rcu_head **nxttail;
-        long            qlen;            /* # of queued callbacks */
-        struct rcu_head *curlist;
-        struct rcu_head **curtail;
-        struct rcu_head *donelist;
-        struct rcu_head **donetail;
-        long            blimit;          /* Upper limit on a processed batch */
-        int cpu;
-        struct rcu_head barrier;
-};
-
-DECLARE_PER_CPU(struct rcu_data, rcu_data);
-DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
-
-/*
- * Increment the quiescent state counter.
- * The counter is a bit degenerated: We do not need to know
- * how many quiescent states passed, just if there was at least
- * one since the start of the grace period. Thus just a flag.
- */
-static inline void rcu_qsctr_inc(int cpu)
-{
-        struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
-        rdp->passed_quiesc = 1;
-}
-static inline void rcu_bh_qsctr_inc(int cpu)
-{
-        struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
-        rdp->passed_quiesc = 1;
-}
-
-extern int rcu_pending(int cpu);
-extern int rcu_needs_cpu(int cpu);
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-extern struct lockdep_map rcu_lock_map;
-# define rcu_read_acquire()     lock_acquire(&rcu_lock_map, 0, 0, 2, 1, _THIS_IP_)
-# define rcu_read_release()     lock_release(&rcu_lock_map, 1, _THIS_IP_)
-#else
-# define rcu_read_acquire()     do { } while (0)
-# define rcu_read_release()     do { } while (0)
-#endif
-
 /**
  * rcu_read_lock - mark the beginning of an RCU read-side critical section.
  *
@@ -172,24 +90,13 @@ extern struct lockdep_map rcu_lock_map;
  *
  * It is illegal to block while in an RCU read-side critical section.
  */
-#define rcu_read_lock() \
-        do { \
-                preempt_disable(); \
-                __acquire(RCU); \
-                rcu_read_acquire(); \
-        } while(0)
+#define rcu_read_lock() __rcu_read_lock()
 
 /**
  * rcu_read_unlock - marks the end of an RCU read-side critical section.
  *
  * See rcu_read_lock() for more information.
  */
-#define rcu_read_unlock() \
-        do { \
-                rcu_read_release(); \
-                __release(RCU); \
-                preempt_enable(); \
-        } while(0)
 
 /*
  * So where is rcu_write_lock()?  It does not exist, as there is no
@@ -200,6 +107,7 @@ extern struct lockdep_map rcu_lock_map;
  * used as well.  RCU does not care how the writers keep out of each
  * others' way, as long as they do so.
  */
+#define rcu_read_unlock() __rcu_read_unlock()
 
 /**
  * rcu_read_lock_bh - mark the beginning of a softirq-only RCU critical section
@@ -212,24 +120,14 @@ extern struct lockdep_map rcu_lock_map;
  * can use just rcu_read_lock().
  *
  */
-#define rcu_read_lock_bh() \
-        do { \
-                local_bh_disable(); \
-                __acquire(RCU_BH); \
-                rcu_read_acquire(); \
-        } while(0)
+#define rcu_read_lock_bh() __rcu_read_lock_bh()
 
 /*
  * rcu_read_unlock_bh - marks the end of a softirq-only RCU critical section
  *
  * See rcu_read_lock_bh() for more information.
  */
-#define rcu_read_unlock_bh() \
-        do { \
-                rcu_read_release(); \
-                __release(RCU_BH); \
-                local_bh_enable(); \
-        } while(0)
+#define rcu_read_unlock_bh() __rcu_read_unlock_bh()
 
 /*
  * Prevent the compiler from merging or refetching accesses.  The compiler
@@ -293,21 +191,53 @@ extern struct lockdep_map rcu_lock_map;
  * In "classic RCU", these two guarantees happen to be one and
  * the same, but can differ in realtime RCU implementations.
  */
-#define synchronize_sched() synchronize_rcu()
+#define synchronize_sched() __synchronize_sched()
+
+/**
+ * call_rcu - Queue an RCU callback for invocation after a grace period.
+ * @head: structure to be used for queueing the RCU updates.
+ * @func: actual update function to be invoked after the grace period
+ *
+ * The update function will be invoked some time after a full grace
+ * period elapses, in other words after all currently executing RCU
+ * read-side critical sections have completed.  RCU read-side critical
+ * sections are delimited by rcu_read_lock() and rcu_read_unlock(),
+ * and may be nested.
+ */
+extern void call_rcu(struct rcu_head *head,
+                              void (*func)(struct rcu_head *head));
+
+/**
+ * call_rcu_bh - Queue an RCU for invocation after a quicker grace period.
+ * @head: structure to be used for queueing the RCU updates.
+ * @func: actual update function to be invoked after the grace period
+ *
+ * The update function will be invoked some time after a full grace
+ * period elapses, in other words after all currently executing RCU
+ * read-side critical sections have completed. call_rcu_bh() assumes
+ * that the read-side critical sections end on completion of a softirq
+ * handler. This means that read-side critical sections in process
+ * context must not be interrupted by softirqs. This interface is to be
+ * used when most of the read-side critical sections are in softirq context.
+ * RCU read-side critical sections are delimited by :
+ *  - rcu_read_lock() and  rcu_read_unlock(), if in interrupt context.
+ *  OR
+ *  - rcu_read_lock_bh() and rcu_read_unlock_bh(), if in process context.
+ *  These may be nested.
+ */
+extern void call_rcu_bh(struct rcu_head *head,
+                        void (*func)(struct rcu_head *head));
+
+/* Exported common interfaces */
+extern void synchronize_rcu(void);
+extern void rcu_barrier(void);
 
+/* Internal to kernel */
 extern void rcu_init(void);
 extern void rcu_check_callbacks(int cpu, int user);
-extern void rcu_restart_cpu(int cpu);
+
 extern long rcu_batches_completed(void);
 extern long rcu_batches_completed_bh(void);
 
-/* Exported interfaces */
-extern void FASTCALL(call_rcu(struct rcu_head *head, 
-                                void (*func)(struct rcu_head *head)));
-extern void FASTCALL(call_rcu_bh(struct rcu_head *head,
-                                void (*func)(struct rcu_head *head)));
-extern void synchronize_rcu(void);
-extern void rcu_barrier(void);
-
 #endif /* __KERNEL__ */
 #endif /* __LINUX_RCUPDATE_H */