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Subject[PATCH tip/core/rcu 09/12] rcutorture: Complete threading rcu_fwd pointers through functions
Date
From: "Paul E. McKenney" <paulmck@kernel.org>

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>
---
kernel/rcu/rcutorture.c | 39 +++++++++++++++++++++------------------
1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 6f540fe..394baac 100644
--- 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. */
--
2.9.5
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