rcutorture: Extract common code from rcu_torture_reader()

This commit extracts the code executed on each pass through the loop
in rcu_torture_reader() into a new rcu_torture_one_read() function.
This new function will also be used by rcu_torture_timer().

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

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 335387fabac2fa8ae9bae60368fafa51097009d9..971e31ae9bcfe898a254dad0a91e50af9cc9a938 100644 (file)
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1089,6 +1089,60 @@ static void rcu_torture_timer_cb(struct rcu_head *rhp)
        kfree(rhp);
 }
 
+/*
+ * Do one read-side critical section, returning false if there was
+ * no data to read.  Can be invoked both from process context and
+ * from a timer handler.
+ */
+static bool rcu_torture_one_read(struct torture_random_state *trsp)
+{
+       int idx;
+       unsigned long started;
+       unsigned long completed;
+       struct rcu_torture *p;
+       int pipe_count;
+       unsigned long long ts;
+
+       idx = cur_ops->readlock();
+       started = cur_ops->get_gp_seq();
+       ts = rcu_trace_clock_local();
+       p = rcu_dereference_check(rcu_torture_current,
+                                 rcu_read_lock_bh_held() ||
+                                 rcu_read_lock_sched_held() ||
+                                 srcu_read_lock_held(srcu_ctlp) ||
+                                 torturing_tasks());
+       if (p == NULL) {
+               /* Wait for rcu_torture_writer to get underway */
+               cur_ops->readunlock(idx);
+               return false;
+       }
+       if (p->rtort_mbtest == 0)
+               atomic_inc(&n_rcu_torture_mberror);
+       cur_ops->read_delay(trsp);
+       preempt_disable();
+       pipe_count = p->rtort_pipe_count;
+       if (pipe_count > RCU_TORTURE_PIPE_LEN) {
+               /* Should not happen, but... */
+               pipe_count = RCU_TORTURE_PIPE_LEN;
+       }
+       completed = cur_ops->get_gp_seq();
+       if (pipe_count > 1) {
+               do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
+                                         ts, started, completed);
+               rcu_ftrace_dump(DUMP_ALL);
+       }
+       __this_cpu_inc(rcu_torture_count[pipe_count]);
+       completed = rcutorture_seq_diff(completed, started);
+       if (completed > RCU_TORTURE_PIPE_LEN) {
+               /* Should not happen, but... */
+               completed = RCU_TORTURE_PIPE_LEN;
+       }
+       __this_cpu_inc(rcu_torture_batch[completed]);
+       preempt_enable();
+       cur_ops->readunlock(idx);
+       return true;
+}
+
 /*
  * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
  * incrementing the corresponding element of the pipeline array.  The
@@ -1165,14 +1219,8 @@ static void rcu_torture_timer(struct timer_list *unused)
 static int
 rcu_torture_reader(void *arg)
 {
-       unsigned long started;
-       unsigned long completed;
-       int idx;
        DEFINE_TORTURE_RANDOM(rand);
-       struct rcu_torture *p;
-       int pipe_count;
        struct timer_list t;
-       unsigned long long ts;
 
        VERBOSE_TOROUT_STRING("rcu_torture_reader task started");
        set_user_nice(current, MAX_NICE);
@@ -1184,44 +1232,8 @@ rcu_torture_reader(void *arg)
                        if (!timer_pending(&t))
                                mod_timer(&t, jiffies + 1);
                }
-               idx = cur_ops->readlock();
-               started = cur_ops->get_gp_seq();
-               ts = rcu_trace_clock_local();
-               p = rcu_dereference_check(rcu_torture_current,
-                                         rcu_read_lock_bh_held() ||
-                                         rcu_read_lock_sched_held() ||
-                                         srcu_read_lock_held(srcu_ctlp) ||
-                                         torturing_tasks());
-               if (p == NULL) {
-                       /* Wait for rcu_torture_writer to get underway */
-                       cur_ops->readunlock(idx);
+               if (!rcu_torture_one_read(&rand))
                        schedule_timeout_interruptible(HZ);
-                       continue;
-               }
-               if (p->rtort_mbtest == 0)
-                       atomic_inc(&n_rcu_torture_mberror);
-               cur_ops->read_delay(&rand);
-               preempt_disable();
-               pipe_count = p->rtort_pipe_count;
-               if (pipe_count > RCU_TORTURE_PIPE_LEN) {
-                       /* Should not happen, but... */
-                       pipe_count = RCU_TORTURE_PIPE_LEN;
-               }
-               completed = cur_ops->get_gp_seq();
-               if (pipe_count > 1) {
-                       do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
-                                                 ts, started, completed);
-                       rcu_ftrace_dump(DUMP_ALL);
-               }
-               __this_cpu_inc(rcu_torture_count[pipe_count]);
-               completed = rcutorture_seq_diff(completed, started);
-               if (completed > RCU_TORTURE_PIPE_LEN) {
-                       /* Should not happen, but... */
-                       completed = RCU_TORTURE_PIPE_LEN;
-               }
-               __this_cpu_inc(rcu_torture_batch[completed]);
-               preempt_enable();
-               cur_ops->readunlock(idx);
                stutter_wait("rcu_torture_reader");
        } while (!torture_must_stop());
        if (irqreader && cur_ops->irq_capable) {