In PREEMPT_RT kernels, both spin_lock() and spin_lock_irq() are converted
to sleepable rt_spin_lock().  This means that the interrupt related suffix
for spin_lock/unlock(_irq, irqsave/irqrestore) do not affect the CPU's
interrupt state. This commit therefore adds raw spin-lock torture tests.
This in turn permits pure spin locks to be tested in PREEMPT_RT kernels.

Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Zqiang <qiang1.zhang@intel.com>
---
 kernel/locking/locktorture.c | 56 +++++++++++++++++++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 9425aff08936..153ddc4c47ef 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -55,7 +55,7 @@ torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)");
 /* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */
 #define MAX_NESTED_LOCKS 8
 
-static char *torture_type = "spin_lock";
+static char *torture_type = IS_ENABLED(CONFIG_PREEMPT_RT) ? "raw_spin_lock" : "spin_lock";
 module_param(torture_type, charp, 0444);
 MODULE_PARM_DESC(torture_type,
 		 "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)");
@@ -257,6 +257,59 @@ static struct lock_torture_ops spin_lock_irq_ops = {
 	.name		= "spin_lock_irq"
 };
 
+static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
+
+static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
+__acquires(torture_raw_spinlock)
+{
+	raw_spin_lock(&torture_raw_spinlock);
+	return 0;
+}
+
+static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
+__releases(torture_raw_spinlock)
+{
+	raw_spin_unlock(&torture_raw_spinlock);
+}
+
+static struct lock_torture_ops raw_spin_lock_ops = {
+	.writelock	= torture_raw_spin_lock_write_lock,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost	= torture_rt_boost,
+	.writeunlock	= torture_raw_spin_lock_write_unlock,
+	.readlock	= NULL,
+	.read_delay	= NULL,
+	.readunlock	= NULL,
+	.name		= "raw_spin_lock"
+};
+
+static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
+__acquires(torture_raw_spinlock)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
+	cxt.cur_ops->flags = flags;
+	return 0;
+}
+
+static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
+__releases(torture_raw_spinlock)
+{
+	raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops raw_spin_lock_irq_ops = {
+	.writelock	= torture_raw_spin_lock_write_lock_irq,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost	= torture_rt_boost,
+	.writeunlock	= torture_raw_spin_lock_write_unlock_irq,
+	.readlock	= NULL,
+	.read_delay	= NULL,
+	.readunlock	= NULL,
+	.name		= "raw_spin_lock_irq"
+};
+
 static DEFINE_RWLOCK(torture_rwlock);
 
 static int torture_rwlock_write_lock(int tid __maybe_unused)
@@ -1017,6 +1070,7 @@ static int __init lock_torture_init(void)
 	static struct lock_torture_ops *torture_ops[] = {
 		&lock_busted_ops,
 		&spin_lock_ops, &spin_lock_irq_ops,
+		&raw_spin_lock_ops, &raw_spin_lock_irq_ops,
 		&rw_lock_ops, &rw_lock_irq_ops,
 		&mutex_lock_ops,
 		&ww_mutex_lock_ops,
-- 
2.25.1

On Fri, 24 Feb 2023, Zqiang wrote:

>In PREEMPT_RT kernels, both spin_lock() and spin_lock_irq() are converted
>to sleepable rt_spin_lock().  This means that the interrupt related suffix
>for spin_lock/unlock(_irq, irqsave/irqrestore) do not affect the CPU's
>interrupt state. This commit therefore adds raw spin-lock torture tests.
>This in turn permits pure spin locks to be tested in PREEMPT_RT kernels.
>
>Suggested-by: Paul E. McKenney <paulmck@kernel.org>
>Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
>Signed-off-by: Zqiang <qiang1.zhang@intel.com>

Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>

On Thu, Feb 23, 2023 at 07:12:32PM -0800, Davidlohr Bueso wrote:
> On Fri, 24 Feb 2023, Zqiang wrote:
> 
> > In PREEMPT_RT kernels, both spin_lock() and spin_lock_irq() are converted
> > to sleepable rt_spin_lock().  This means that the interrupt related suffix
> > for spin_lock/unlock(_irq, irqsave/irqrestore) do not affect the CPU's
> > interrupt state. This commit therefore adds raw spin-lock torture tests.
> > This in turn permits pure spin locks to be tested in PREEMPT_RT kernels.
> > 
> > Suggested-by: Paul E. McKenney <paulmck@kernel.org>
> > Suggested-by: Davidlohr Bueso <dave@stgolabs.net>
> > Signed-off-by: Zqiang <qiang1.zhang@intel.com>
> 
> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>

Queued replacing the previous version, thank you both!

							Thanx, Paul