Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull additional commits for locktorture, from Paul E. McKenney.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

6 files changed, 140 insertions, 19 deletions

diff --git a/Documentation/locking/locktorture.txt b/Documentation/locking/locktorture.txt
index be715015e0f7..619f2bb136a5 100644
--- a/Documentation/locking/locktorture.txt
+++ b/Documentation/locking/locktorture.txt
@@ -45,6 +45,11 @@ torture_type	  Type of lock to torture. By default, only spinlocks will
                      o "spin_lock_irq": spin_lock_irq() and spin_unlock_irq()
                                         pairs.
 
+                     o "rw_lock": read/write lock() and unlock() rwlock pairs.
+
+                     o "rw_lock_irq": read/write lock_irq() and unlock_irq()
+                                      rwlock pairs.
+
                      o "mutex_lock": mutex_lock() and mutex_unlock() pairs.
 
                      o "rwsem_lock": read/write down() and up() semaphore pairs.
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 540d5dfe1112..ec8cce259779 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -20,31 +20,20 @@
  * Author: Paul E. McKenney <paulmck@us.ibm.com>
  *      Based on kernel/rcu/torture.c.
  */
-#include <linux/types.h>
 #include <linux/kernel.h>
-#include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kthread.h>
-#include <linux/err.h>
 #include <linux/spinlock.h>
+#include <linux/rwlock.h>
 #include <linux/mutex.h>
+#include <linux/rwsem.h>
 #include <linux/smp.h>
 #include <linux/interrupt.h>
 #include <linux/sched.h>
 #include <linux/atomic.h>
-#include <linux/bitops.h>
-#include <linux/completion.h>
 #include <linux/moduleparam.h>
-#include <linux/percpu.h>
-#include <linux/notifier.h>
-#include <linux/reboot.h>
-#include <linux/freezer.h>
-#include <linux/cpu.h>
 #include <linux/delay.h>
-#include <linux/stat.h>
 #include <linux/slab.h>
-#include <linux/trace_clock.h>
-#include <asm/byteorder.h>
 #include <linux/torture.h>
 
 MODULE_LICENSE("GPL");
@@ -204,7 +193,7 @@ static struct lock_torture_ops spin_lock_ops = {
 };
 
 static int torture_spin_lock_write_lock_irq(void)
-__acquires(torture_spinlock_irq)
+__acquires(torture_spinlock)
 {
         unsigned long flags;
 
@@ -229,6 +218,110 @@ static struct lock_torture_ops spin_lock_irq_ops = {
         .name           = "spin_lock_irq"
 };
 
+static DEFINE_RWLOCK(torture_rwlock);
+
+static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)
+{
+        write_lock(&torture_rwlock);
+        return 0;
+}
+
+static void torture_rwlock_write_delay(struct torture_random_state *trsp)
+{
+        const unsigned long shortdelay_us = 2;
+        const unsigned long longdelay_ms = 100;
+
+        /* We want a short delay mostly to emulate likely code, and
+         * we want a long delay occasionally to force massive contention.
+         */
+        if (!(torture_random(trsp) %
+              (cxt.nrealwriters_stress * 2000 * longdelay_ms)))
+                mdelay(longdelay_ms);
+        else
+                udelay(shortdelay_us);
+}
+
+static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)
+{
+        write_unlock(&torture_rwlock);
+}
+
+static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)
+{
+        read_lock(&torture_rwlock);
+        return 0;
+}
+
+static void torture_rwlock_read_delay(struct torture_random_state *trsp)
+{
+        const unsigned long shortdelay_us = 10;
+        const unsigned long longdelay_ms = 100;
+
+        /* We want a short delay mostly to emulate likely code, and
+         * we want a long delay occasionally to force massive contention.
+         */
+        if (!(torture_random(trsp) %
+              (cxt.nrealreaders_stress * 2000 * longdelay_ms)))
+                mdelay(longdelay_ms);
+        else
+                udelay(shortdelay_us);
+}
+
+static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)
+{
+        read_unlock(&torture_rwlock);
+}
+
+static struct lock_torture_ops rw_lock_ops = {
+        .writelock      = torture_rwlock_write_lock,
+        .write_delay    = torture_rwlock_write_delay,
+        .writeunlock    = torture_rwlock_write_unlock,
+        .readlock       = torture_rwlock_read_lock,
+        .read_delay     = torture_rwlock_read_delay,
+        .readunlock     = torture_rwlock_read_unlock,
+        .name           = "rw_lock"
+};
+
+static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)
+{
+        unsigned long flags;
+
+        write_lock_irqsave(&torture_rwlock, flags);
+        cxt.cur_ops->flags = flags;
+        return 0;
+}
+
+static void torture_rwlock_write_unlock_irq(void)
+__releases(torture_rwlock)
+{
+        write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
+}
+
+static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)
+{
+        unsigned long flags;
+
+        read_lock_irqsave(&torture_rwlock, flags);
+        cxt.cur_ops->flags = flags;
+        return 0;
+}
+
+static void torture_rwlock_read_unlock_irq(void)
+__releases(torture_rwlock)
+{
+        write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops rw_lock_irq_ops = {
+        .writelock      = torture_rwlock_write_lock_irq,
+        .write_delay    = torture_rwlock_write_delay,
+        .writeunlock    = torture_rwlock_write_unlock_irq,
+        .readlock       = torture_rwlock_read_lock_irq,
+        .read_delay     = torture_rwlock_read_delay,
+        .readunlock     = torture_rwlock_read_unlock_irq,
+        .name           = "rw_lock_irq"
+};
+
 static DEFINE_MUTEX(torture_mutex);
 
 static int torture_mutex_lock(void) __acquires(torture_mutex)
@@ -348,14 +441,19 @@ static int lock_torture_writer(void *arg)
         do {
                 if ((torture_random(&rand) & 0xfffff) == 0)
                         schedule_timeout_uninterruptible(1);
+
                 cxt.cur_ops->writelock();
                 if (WARN_ON_ONCE(lock_is_write_held))
                         lwsp->n_lock_fail++;
                 lock_is_write_held = 1;
+                if (WARN_ON_ONCE(lock_is_read_held))
+                        lwsp->n_lock_fail++; /* rare, but... */
+
                 lwsp->n_lock_acquired++;
                 cxt.cur_ops->write_delay(&rand);
                 lock_is_write_held = 0;
                 cxt.cur_ops->writeunlock();
+
                 stutter_wait("lock_torture_writer");
         } while (!torture_must_stop());
         torture_kthread_stopping("lock_torture_writer");
@@ -377,12 +475,17 @@ static int lock_torture_reader(void *arg)
         do {
                 if ((torture_random(&rand) & 0xfffff) == 0)
                         schedule_timeout_uninterruptible(1);
+
                 cxt.cur_ops->readlock();
                 lock_is_read_held = 1;
+                if (WARN_ON_ONCE(lock_is_write_held))
+                        lrsp->n_lock_fail++; /* rare, but... */
+
                 lrsp->n_lock_acquired++;
                 cxt.cur_ops->read_delay(&rand);
                 lock_is_read_held = 0;
                 cxt.cur_ops->readunlock();
+
                 stutter_wait("lock_torture_reader");
         } while (!torture_must_stop());
         torture_kthread_stopping("lock_torture_reader");
@@ -535,8 +638,11 @@ static int __init lock_torture_init(void)
         int i, j;
         int firsterr = 0;
         static struct lock_torture_ops *torture_ops[] = {
-                &lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops,
-                &mutex_lock_ops, &rwsem_lock_ops,
+                &lock_busted_ops,
+                &spin_lock_ops, &spin_lock_irq_ops,
+                &rw_lock_ops, &rw_lock_irq_ops,
+                &mutex_lock_ops,
+                &rwsem_lock_ops,
         };
 
         if (!torture_init_begin(torture_type, verbose, &torture_runnable))
@@ -571,7 +677,8 @@ static int __init lock_torture_init(void)
                 cxt.debug_lock = true;
 #endif
 #ifdef CONFIG_DEBUG_SPINLOCK
-        if (strncmp(torture_type, "spin", 4) == 0)
+        if ((strncmp(torture_type, "spin", 4) == 0) ||
+            (strncmp(torture_type, "rw_lock", 7) == 0))
                 cxt.debug_lock = true;
 #endif
 
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 5dbe22aa3efd..09b685daee3d 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2043,9 +2043,10 @@ __acquires(&pool->lock)
          * kernels, where a requeueing work item waiting for something to
          * happen could deadlock with stop_machine as such work item could
          * indefinitely requeue itself while all other CPUs are trapped in
-         * stop_machine.
+         * stop_machine. At the same time, report a quiescent RCU state so
+         * the same condition doesn't freeze RCU.
          */
-        cond_resched();
+        cond_resched_rcu_qs();
 
         spin_lock_irq(&pool->lock);
 
diff --git a/tools/testing/selftests/rcutorture/configs/lock/CFLIST b/tools/testing/selftests/rcutorture/configs/lock/CFLIST
index 6108137da770..6910b7370761 100644
--- a/tools/testing/selftests/rcutorture/configs/lock/CFLIST
+++ b/tools/testing/selftests/rcutorture/configs/lock/CFLIST
@@ -1,3 +1,4 @@
 LOCK01
 LOCK02
 LOCK03
+LOCK04
\ No newline at end of file
diff --git a/tools/testing/selftests/rcutorture/configs/lock/LOCK04 b/tools/testing/selftests/rcutorture/configs/lock/LOCK04
new file mode 100644
index 000000000000..1d1da1477fc3
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/lock/LOCK04
@@ -0,0 +1,6 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=4
+CONFIG_HOTPLUG_CPU=y
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y
diff --git a/tools/testing/selftests/rcutorture/configs/lock/LOCK04.boot b/tools/testing/selftests/rcutorture/configs/lock/LOCK04.boot
new file mode 100644
index 000000000000..48c04fe47fb4
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/lock/LOCK04.boot
@@ -0,0 +1 @@
+locktorture.torture_type=rw_lock