These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / kernel / rcu / srcu.c

diff --git a/kernel/kernel/rcu/srcu.c b/kernel/kernel/rcu/srcu.c
index cad76e7..a63a1ea 100644 (file)
--- a/kernel/kernel/rcu/srcu.c
+++ b/kernel/kernel/rcu/srcu.c
@@ -151,7 +151,7 @@ static unsigned long srcu_readers_seq_idx(struct srcu_struct *sp, int idx)
        unsigned long t;
 
        for_each_possible_cpu(cpu) {
-               t = ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->seq[idx]);
+               t = READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->seq[idx]);
                sum += t;
        }
        return sum;
@@ -168,7 +168,7 @@ static unsigned long srcu_readers_active_idx(struct srcu_struct *sp, int idx)
        unsigned long t;
 
        for_each_possible_cpu(cpu) {
-               t = ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[idx]);
+               t = READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[idx]);
                sum += t;
        }
        return sum;
@@ -252,21 +252,22 @@ static bool srcu_readers_active_idx_check(struct srcu_struct *sp, int idx)
 }
 
 /**
- * srcu_readers_active - returns approximate number of readers.
+ * srcu_readers_active - returns true if there are readers. and false
+ *                       otherwise
  * @sp: which srcu_struct to count active readers (holding srcu_read_lock).
  *
  * Note that this is not an atomic primitive, and can therefore suffer
  * severe errors when invoked on an active srcu_struct.  That said, it
  * can be useful as an error check at cleanup time.
  */
-static int srcu_readers_active(struct srcu_struct *sp)
+static bool srcu_readers_active(struct srcu_struct *sp)
 {
        int cpu;
        unsigned long sum = 0;
 
        for_each_possible_cpu(cpu) {
-               sum += ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[0]);
-               sum += ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[1]);
+               sum += READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[0]);
+               sum += READ_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[1]);
        }
        return sum;
 }
@@ -296,12 +297,10 @@ int __srcu_read_lock(struct srcu_struct *sp)
 {
        int idx;
 
-       idx = ACCESS_ONCE(sp->completed) & 0x1;
-       preempt_disable();
+       idx = READ_ONCE(sp->completed) & 0x1;
        __this_cpu_inc(sp->per_cpu_ref->c[idx]);
        smp_mb(); /* B */  /* Avoid leaking the critical section. */
        __this_cpu_inc(sp->per_cpu_ref->seq[idx]);
-       preempt_enable();
        return idx;
 }
 EXPORT_SYMBOL_GPL(__srcu_read_lock);
@@ -386,7 +385,7 @@ static void srcu_flip(struct srcu_struct *sp)
  * srcu_struct structure.
  */
 void call_srcu(struct srcu_struct *sp, struct rcu_head *head,
-               void (*func)(struct rcu_head *head))
+              rcu_callback_t func)
 {
        unsigned long flags;
 
@@ -414,11 +413,11 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount)
        struct rcu_head *head = &rcu.head;
        bool done = false;
 
-       rcu_lockdep_assert(!lock_is_held(&sp->dep_map) &&
-                          !lock_is_held(&rcu_bh_lock_map) &&
-                          !lock_is_held(&rcu_lock_map) &&
-                          !lock_is_held(&rcu_sched_lock_map),
-                          "Illegal synchronize_srcu() in same-type SRCU (or RCU) read-side critical section");
+       RCU_LOCKDEP_WARN(lock_is_held(&sp->dep_map) ||
+                        lock_is_held(&rcu_bh_lock_map) ||
+                        lock_is_held(&rcu_lock_map) ||
+                        lock_is_held(&rcu_sched_lock_map),
+                        "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section");
 
        might_sleep();
        init_completion(&rcu.completion);