rcu: Consolidate tree/tiny __rcu_read_{,un}lock() implementations
The CONFIG_TREE_PREEMPT_RCU and CONFIG_TINY_PREEMPT_RCU versions of
__rcu_read_lock() and __rcu_read_unlock() are identical, so this commit
consolidates them into kernel/rcupdate.h.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 3e48994..4b6b17c 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -78,7 +78,6 @@
DEFINE_PER_CPU(struct rcu_data, rcu_preempt_data);
static struct rcu_state *rcu_state = &rcu_preempt_state;
-static void rcu_read_unlock_special(struct task_struct *t);
static int rcu_preempted_readers_exp(struct rcu_node *rnp);
/*
@@ -233,18 +232,6 @@
}
/*
- * Tree-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 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.
@@ -310,7 +297,7 @@
* notify RCU core processing or task having blocked during the RCU
* read-side critical section.
*/
-static noinline void rcu_read_unlock_special(struct task_struct *t)
+void rcu_read_unlock_special(struct task_struct *t)
{
int empty;
int empty_exp;
@@ -418,38 +405,6 @@
}
}
-/*
- * Tree-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;
-
- if (t->rcu_read_lock_nesting != 1)
- --t->rcu_read_lock_nesting;
- else {
- barrier(); /* critical section before exit code. */
- t->rcu_read_lock_nesting = INT_MIN;
- barrier(); /* assign before ->rcu_read_unlock_special load */
- if (unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
- rcu_read_unlock_special(t);
- barrier(); /* ->rcu_read_unlock_special load before assign */
- t->rcu_read_lock_nesting = 0;
- }
-#ifdef CONFIG_PROVE_LOCKING
- {
- int rrln = ACCESS_ONCE(t->rcu_read_lock_nesting);
-
- WARN_ON_ONCE(rrln < 0 && rrln > INT_MIN / 2);
- }
-#endif /* #ifdef CONFIG_PROVE_LOCKING */
-}
-EXPORT_SYMBOL_GPL(__rcu_read_unlock);
-
#ifdef CONFIG_RCU_CPU_STALL_VERBOSE
/*