rcutorture: Complete threading rcu_fwd pointers through functions

This commit threads pointers to rcu_fwd structures through the remaining
functions using rcu_fwds directly, namely rcu_torture_fwd_prog_cbfree(),
rcutorture_oom_notify() and rcu_torture_fwd_prog_init().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 6f540fe..394baac 100644 (file)
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1754,23 +1754,23 @@ static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
  * Free all callbacks on the rcu_fwd_cb_head list, either because the
  * test is over or because we hit an OOM event.
  */
-static unsigned long rcu_torture_fwd_prog_cbfree(void)
+static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
 {
        unsigned long flags;
        unsigned long freed = 0;
        struct rcu_fwd_cb *rfcp;
 
        for (;;) {
-               spin_lock_irqsave(&rcu_fwds.rcu_fwd_lock, flags);
-               rfcp = rcu_fwds.rcu_fwd_cb_head;
+               spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
+               rfcp = rfp->rcu_fwd_cb_head;
                if (!rfcp) {
-                       spin_unlock_irqrestore(&rcu_fwds.rcu_fwd_lock, flags);
+                       spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
                        break;
                }
-               rcu_fwds.rcu_fwd_cb_head = rfcp->rfc_next;
-               if (!rcu_fwds.rcu_fwd_cb_head)
-                       rcu_fwds.rcu_fwd_cb_tail = &rcu_fwds.rcu_fwd_cb_head;
-               spin_unlock_irqrestore(&rcu_fwds.rcu_fwd_lock, flags);
+               rfp->rcu_fwd_cb_head = rfcp->rfc_next;
+               if (!rfp->rcu_fwd_cb_head)
+                       rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
+               spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
                kfree(rfcp);
                freed++;
                rcu_torture_fwd_prog_cond_resched(freed);
@@ -1926,7 +1926,7 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
        cver = READ_ONCE(rcu_torture_current_version) - cver;
        gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
        cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
-       (void)rcu_torture_fwd_prog_cbfree();
+       (void)rcu_torture_fwd_prog_cbfree(rfp);
 
        if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
            !shutdown_time_arrived()) {
@@ -1952,20 +1952,22 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
 static int rcutorture_oom_notify(struct notifier_block *self,
                                 unsigned long notused, void *nfreed)
 {
+       struct rcu_fwd *rfp = &rcu_fwds;
+
        WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
             __func__);
-       rcu_torture_fwd_cb_hist(&rcu_fwds);
-       rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwds.rcu_fwd_startat)) / 2);
+       rcu_torture_fwd_cb_hist(rfp);
+       rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2);
        WRITE_ONCE(rcu_fwd_emergency_stop, true);
        smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
        pr_info("%s: Freed %lu RCU callbacks.\n",
-               __func__, rcu_torture_fwd_prog_cbfree());
+               __func__, rcu_torture_fwd_prog_cbfree(rfp));
        rcu_barrier();
        pr_info("%s: Freed %lu RCU callbacks.\n",
-               __func__, rcu_torture_fwd_prog_cbfree());
+               __func__, rcu_torture_fwd_prog_cbfree(rfp));
        rcu_barrier();
        pr_info("%s: Freed %lu RCU callbacks.\n",
-               __func__, rcu_torture_fwd_prog_cbfree());
+               __func__, rcu_torture_fwd_prog_cbfree(rfp));
        smp_mb(); /* Frees before return to avoid redoing OOM. */
        (*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
        pr_info("%s returning after OOM processing.\n", __func__);
@@ -2008,6 +2010,8 @@ static int rcu_torture_fwd_prog(void *args)
 /* If forward-progress checking is requested and feasible, spawn the thread. */
 static int __init rcu_torture_fwd_prog_init(void)
 {
+       struct rcu_fwd *rfp = &rcu_fwds;
+
        if (!fwd_progress)
                return 0; /* Not requested, so don't do it. */
        if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 ||
@@ -2022,14 +2026,13 @@ static int __init rcu_torture_fwd_prog_init(void)
                WARN_ON(1); /* Make sure rcutorture notices conflict. */
                return 0;
        }
-       spin_lock_init(&rcu_fwds.rcu_fwd_lock);
-       rcu_fwds.rcu_fwd_cb_tail = &rcu_fwds.rcu_fwd_cb_head;
+       spin_lock_init(&rfp->rcu_fwd_lock);
+       rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
        if (fwd_progress_holdoff <= 0)
                fwd_progress_holdoff = 1;
        if (fwd_progress_div <= 0)
                fwd_progress_div = 4;
-       return torture_create_kthread(rcu_torture_fwd_prog,
-                                     &rcu_fwds, fwd_prog_task);
+       return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task);
 }
 
 /* Callback function for RCU barrier testing. */