mmc: s3c6410: enable ADMA feature in 6410 sdhci controller
[safe/jmp/linux-2.6] / kernel / rcutorture.c
index 3245b40..6535ac8 100644 (file)
@@ -18,7 +18,7 @@
  * Copyright (C) IBM Corporation, 2005, 2006
  *
  * Authors: Paul E. McKenney <paulmck@us.ibm.com>
- *          Josh Triplett <josh@freedesktop.org>
+ *       Josh Triplett <josh@freedesktop.org>
  *
  * See also:  Documentation/RCU/torture.txt
  */
@@ -50,7 +50,7 @@
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
-              "Josh Triplett <josh@freedesktop.org>");
+             "Josh Triplett <josh@freedesktop.org>");
 
 static int nreaders = -1;      /* # reader threads, defaults to 2*ncpus */
 static int nfakewriters = 4;   /* # fake writer threads */
@@ -61,6 +61,9 @@ static int test_no_idle_hz;   /* Test RCU's support for tickless idle CPUs. */
 static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
 static int stutter = 5;                /* Start/stop testing interval (in sec) */
 static int irqreader = 1;      /* RCU readers from irq (timers). */
+static int fqs_duration = 0;   /* Duration of bursts (us), 0 to disable. */
+static int fqs_holdoff = 0;    /* Hold time within burst (us). */
+static int fqs_stutter = 3;    /* Wait time between bursts (s). */
 static char *torture_type = "rcu"; /* What RCU implementation to torture. */
 
 module_param(nreaders, int, 0444);
@@ -79,6 +82,12 @@ module_param(stutter, int, 0444);
 MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
 module_param(irqreader, int, 0444);
 MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
+module_param(fqs_duration, int, 0444);
+MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)");
+module_param(fqs_holdoff, int, 0444);
+MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
+module_param(fqs_stutter, int, 0444);
+MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
 module_param(torture_type, charp, 0444);
 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
 
@@ -99,6 +108,7 @@ static struct task_struct **reader_tasks;
 static struct task_struct *stats_task;
 static struct task_struct *shuffler_task;
 static struct task_struct *stutter_task;
+static struct task_struct *fqs_task;
 
 #define RCU_TORTURE_PIPE_LEN 10
 
@@ -110,8 +120,8 @@ struct rcu_torture {
 };
 
 static LIST_HEAD(rcu_torture_freelist);
-static struct rcu_torture *rcu_torture_current = NULL;
-static long rcu_torture_current_version = 0;
+static struct rcu_torture *rcu_torture_current;
+static long rcu_torture_current_version;
 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
 static DEFINE_SPINLOCK(rcu_torture_lock);
 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
@@ -124,10 +134,11 @@ static atomic_t n_rcu_torture_alloc_fail;
 static atomic_t n_rcu_torture_free;
 static atomic_t n_rcu_torture_mberror;
 static atomic_t n_rcu_torture_error;
-static long n_rcu_torture_timers = 0;
+static long n_rcu_torture_timers;
 static struct list_head rcu_torture_removed;
+static cpumask_var_t shuffle_tmp_mask;
 
-static int stutter_pause_test = 0;
+static int stutter_pause_test;
 
 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
 #define RCUTORTURE_RUNNABLE_INIT 1
@@ -136,31 +147,47 @@ static int stutter_pause_test = 0;
 #endif
 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
 
-#define FULLSTOP_SIGNALED 1    /* Bail due to signal. */
-#define FULLSTOP_CLEANUP  2    /* Orderly shutdown. */
-static int fullstop;           /* stop generating callbacks at test end. */
-DEFINE_MUTEX(fullstop_mutex);  /* protect fullstop transitions and */
-                               /*  spawning of kthreads. */
+/* Mediate rmmod and system shutdown.  Concurrent rmmod & shutdown illegal! */
+
+#define FULLSTOP_DONTSTOP 0    /* Normal operation. */
+#define FULLSTOP_SHUTDOWN 1    /* System shutdown with rcutorture running. */
+#define FULLSTOP_RMMOD    2    /* Normal rmmod of rcutorture. */
+static int fullstop = FULLSTOP_RMMOD;
+DEFINE_MUTEX(fullstop_mutex);  /* Protect fullstop transitions and spawning */
+                               /*  of kthreads. */
 
 /*
- * Detect and respond to a signal-based shutdown.
+ * Detect and respond to a system shutdown.
  */
 static int
 rcutorture_shutdown_notify(struct notifier_block *unused1,
                           unsigned long unused2, void *unused3)
 {
-       if (fullstop)
-               return NOTIFY_DONE;
-       if (signal_pending(current)) {
-               mutex_lock(&fullstop_mutex);
-               if (!ACCESS_ONCE(fullstop))
-                       fullstop = FULLSTOP_SIGNALED;
-               mutex_unlock(&fullstop_mutex);
-       }
+       mutex_lock(&fullstop_mutex);
+       if (fullstop == FULLSTOP_DONTSTOP)
+               fullstop = FULLSTOP_SHUTDOWN;
+       else
+               printk(KERN_WARNING /* but going down anyway, so... */
+                      "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
+       mutex_unlock(&fullstop_mutex);
        return NOTIFY_DONE;
 }
 
 /*
+ * Absorb kthreads into a kernel function that won't return, so that
+ * they won't ever access module text or data again.
+ */
+static void rcutorture_shutdown_absorb(char *title)
+{
+       if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
+               printk(KERN_NOTICE
+                      "rcutorture thread %s parking due to system shutdown\n",
+                      title);
+               schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
+       }
+}
+
+/*
  * Allocate an element from the rcu_tortures pool.
  */
 static struct rcu_torture *
@@ -221,13 +248,14 @@ rcu_random(struct rcu_random_state *rrsp)
 }
 
 static void
-rcu_stutter_wait(void)
+rcu_stutter_wait(char *title)
 {
-       while ((stutter_pause_test || !rcutorture_runnable) && !fullstop) {
+       while (stutter_pause_test || !rcutorture_runnable) {
                if (rcutorture_runnable)
                        schedule_timeout_interruptible(1);
                else
                        schedule_timeout_interruptible(round_jiffies_relative(HZ));
+               rcutorture_shutdown_absorb(title);
        }
 }
 
@@ -239,17 +267,19 @@ struct rcu_torture_ops {
        void (*init)(void);
        void (*cleanup)(void);
        int (*readlock)(void);
-       void (*readdelay)(struct rcu_random_state *rrsp);
+       void (*read_delay)(struct rcu_random_state *rrsp);
        void (*readunlock)(int idx);
        int (*completed)(void);
-       void (*deferredfree)(struct rcu_torture *p);
+       void (*deferred_free)(struct rcu_torture *p);
        void (*sync)(void);
        void (*cb_barrier)(void);
+       void (*fqs)(void);
        int (*stats)(char *page);
-       int irqcapable;
+       int irq_capable;
        char *name;
 };
-static struct rcu_torture_ops *cur_ops = NULL;
+
+static struct rcu_torture_ops *cur_ops;
 
 /*
  * Definitions for rcu torture testing.
@@ -263,14 +293,17 @@ static int rcu_torture_read_lock(void) __acquires(RCU)
 
 static void rcu_read_delay(struct rcu_random_state *rrsp)
 {
-       long delay;
-       const long longdelay = 200;
+       const unsigned long shortdelay_us = 200;
+       const unsigned long longdelay_ms = 50;
 
-       /* We want there to be long-running readers, but not all the time. */
+       /* We want a short delay sometimes to make a reader delay the grace
+        * period, and we want a long delay occasionally to trigger
+        * force_quiescent_state. */
 
-       delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay);
-       if (!delay)
-               udelay(longdelay);
+       if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
+               mdelay(longdelay_ms);
+       if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
+               udelay(shortdelay_us);
 }
 
 static void rcu_torture_read_unlock(int idx) __releases(RCU)
@@ -289,7 +322,7 @@ rcu_torture_cb(struct rcu_head *p)
        int i;
        struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
 
-       if (fullstop) {
+       if (fullstop != FULLSTOP_DONTSTOP) {
                /* Test is ending, just drop callbacks on the floor. */
                /* The next initialization will pick up the pieces. */
                return;
@@ -302,7 +335,12 @@ rcu_torture_cb(struct rcu_head *p)
                rp->rtort_mbtest = 0;
                rcu_torture_free(rp);
        } else
-               cur_ops->deferredfree(rp);
+               cur_ops->deferred_free(rp);
+}
+
+static int rcu_no_completed(void)
+{
+       return 0;
 }
 
 static void rcu_torture_deferred_free(struct rcu_torture *p)
@@ -311,18 +349,19 @@ static void rcu_torture_deferred_free(struct rcu_torture *p)
 }
 
 static struct rcu_torture_ops rcu_ops = {
-       .init = NULL,
-       .cleanup = NULL,
-       .readlock = rcu_torture_read_lock,
-       .readdelay = rcu_read_delay,
-       .readunlock = rcu_torture_read_unlock,
-       .completed = rcu_torture_completed,
-       .deferredfree = rcu_torture_deferred_free,
-       .sync = synchronize_rcu,
-       .cb_barrier = rcu_barrier,
-       .stats = NULL,
-       .irqcapable = 1,
-       .name = "rcu"
+       .init           = NULL,
+       .cleanup        = NULL,
+       .readlock       = rcu_torture_read_lock,
+       .read_delay     = rcu_read_delay,
+       .readunlock     = rcu_torture_read_unlock,
+       .completed      = rcu_torture_completed,
+       .deferred_free  = rcu_torture_deferred_free,
+       .sync           = synchronize_rcu,
+       .cb_barrier     = rcu_barrier,
+       .fqs            = rcu_force_quiescent_state,
+       .stats          = NULL,
+       .irq_capable    = 1,
+       .name           = "rcu"
 };
 
 static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
@@ -352,18 +391,35 @@ static void rcu_sync_torture_init(void)
 }
 
 static struct rcu_torture_ops rcu_sync_ops = {
-       .init = rcu_sync_torture_init,
-       .cleanup = NULL,
-       .readlock = rcu_torture_read_lock,
-       .readdelay = rcu_read_delay,
-       .readunlock = rcu_torture_read_unlock,
-       .completed = rcu_torture_completed,
-       .deferredfree = rcu_sync_torture_deferred_free,
-       .sync = synchronize_rcu,
-       .cb_barrier = NULL,
-       .stats = NULL,
-       .irqcapable = 1,
-       .name = "rcu_sync"
+       .init           = rcu_sync_torture_init,
+       .cleanup        = NULL,
+       .readlock       = rcu_torture_read_lock,
+       .read_delay     = rcu_read_delay,
+       .readunlock     = rcu_torture_read_unlock,
+       .completed      = rcu_torture_completed,
+       .deferred_free  = rcu_sync_torture_deferred_free,
+       .sync           = synchronize_rcu,
+       .cb_barrier     = NULL,
+       .fqs            = rcu_force_quiescent_state,
+       .stats          = NULL,
+       .irq_capable    = 1,
+       .name           = "rcu_sync"
+};
+
+static struct rcu_torture_ops rcu_expedited_ops = {
+       .init           = rcu_sync_torture_init,
+       .cleanup        = NULL,
+       .readlock       = rcu_torture_read_lock,
+       .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
+       .readunlock     = rcu_torture_read_unlock,
+       .completed      = rcu_no_completed,
+       .deferred_free  = rcu_sync_torture_deferred_free,
+       .sync           = synchronize_rcu_expedited,
+       .cb_barrier     = NULL,
+       .fqs            = rcu_force_quiescent_state,
+       .stats          = NULL,
+       .irq_capable    = 1,
+       .name           = "rcu_expedited"
 };
 
 /*
@@ -408,39 +464,43 @@ static void rcu_bh_torture_synchronize(void)
 {
        struct rcu_bh_torture_synchronize rcu;
 
+       init_rcu_head_on_stack(&rcu.head);
        init_completion(&rcu.completion);
        call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
        wait_for_completion(&rcu.completion);
+       destroy_rcu_head_on_stack(&rcu.head);
 }
 
 static struct rcu_torture_ops rcu_bh_ops = {
-       .init = NULL,
-       .cleanup = NULL,
-       .readlock = rcu_bh_torture_read_lock,
-       .readdelay = rcu_read_delay,  /* just reuse rcu's version. */
-       .readunlock = rcu_bh_torture_read_unlock,
-       .completed = rcu_bh_torture_completed,
-       .deferredfree = rcu_bh_torture_deferred_free,
-       .sync = rcu_bh_torture_synchronize,
-       .cb_barrier = rcu_barrier_bh,
-       .stats = NULL,
-       .irqcapable = 1,
-       .name = "rcu_bh"
+       .init           = NULL,
+       .cleanup        = NULL,
+       .readlock       = rcu_bh_torture_read_lock,
+       .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
+       .readunlock     = rcu_bh_torture_read_unlock,
+       .completed      = rcu_bh_torture_completed,
+       .deferred_free  = rcu_bh_torture_deferred_free,
+       .sync           = rcu_bh_torture_synchronize,
+       .cb_barrier     = rcu_barrier_bh,
+       .fqs            = rcu_bh_force_quiescent_state,
+       .stats          = NULL,
+       .irq_capable    = 1,
+       .name           = "rcu_bh"
 };
 
 static struct rcu_torture_ops rcu_bh_sync_ops = {
-       .init = rcu_sync_torture_init,
-       .cleanup = NULL,
-       .readlock = rcu_bh_torture_read_lock,
-       .readdelay = rcu_read_delay,  /* just reuse rcu's version. */
-       .readunlock = rcu_bh_torture_read_unlock,
-       .completed = rcu_bh_torture_completed,
-       .deferredfree = rcu_sync_torture_deferred_free,
-       .sync = rcu_bh_torture_synchronize,
-       .cb_barrier = NULL,
-       .stats = NULL,
-       .irqcapable = 1,
-       .name = "rcu_bh_sync"
+       .init           = rcu_sync_torture_init,
+       .cleanup        = NULL,
+       .readlock       = rcu_bh_torture_read_lock,
+       .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
+       .readunlock     = rcu_bh_torture_read_unlock,
+       .completed      = rcu_bh_torture_completed,
+       .deferred_free  = rcu_sync_torture_deferred_free,
+       .sync           = rcu_bh_torture_synchronize,
+       .cb_barrier     = NULL,
+       .fqs            = rcu_bh_force_quiescent_state,
+       .stats          = NULL,
+       .irq_capable    = 1,
+       .name           = "rcu_bh_sync"
 };
 
 /*
@@ -512,17 +572,36 @@ static int srcu_torture_stats(char *page)
 }
 
 static struct rcu_torture_ops srcu_ops = {
-       .init = srcu_torture_init,
-       .cleanup = srcu_torture_cleanup,
-       .readlock = srcu_torture_read_lock,
-       .readdelay = srcu_read_delay,
-       .readunlock = srcu_torture_read_unlock,
-       .completed = srcu_torture_completed,
-       .deferredfree = rcu_sync_torture_deferred_free,
-       .sync = srcu_torture_synchronize,
-       .cb_barrier = NULL,
-       .stats = srcu_torture_stats,
-       .name = "srcu"
+       .init           = srcu_torture_init,
+       .cleanup        = srcu_torture_cleanup,
+       .readlock       = srcu_torture_read_lock,
+       .read_delay     = srcu_read_delay,
+       .readunlock     = srcu_torture_read_unlock,
+       .completed      = srcu_torture_completed,
+       .deferred_free  = rcu_sync_torture_deferred_free,
+       .sync           = srcu_torture_synchronize,
+       .cb_barrier     = NULL,
+       .stats          = srcu_torture_stats,
+       .name           = "srcu"
+};
+
+static void srcu_torture_synchronize_expedited(void)
+{
+       synchronize_srcu_expedited(&srcu_ctl);
+}
+
+static struct rcu_torture_ops srcu_expedited_ops = {
+       .init           = srcu_torture_init,
+       .cleanup        = srcu_torture_cleanup,
+       .readlock       = srcu_torture_read_lock,
+       .read_delay     = srcu_read_delay,
+       .readunlock     = srcu_torture_read_unlock,
+       .completed      = srcu_torture_completed,
+       .deferred_free  = rcu_sync_torture_deferred_free,
+       .sync           = srcu_torture_synchronize_expedited,
+       .cb_barrier     = NULL,
+       .stats          = srcu_torture_stats,
+       .name           = "srcu_expedited"
 };
 
 /*
@@ -540,11 +619,6 @@ static void sched_torture_read_unlock(int idx)
        preempt_enable();
 }
 
-static int sched_torture_completed(void)
-{
-       return 0;
-}
-
 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
 {
        call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
@@ -556,35 +630,85 @@ static void sched_torture_synchronize(void)
 }
 
 static struct rcu_torture_ops sched_ops = {
-       .init = rcu_sync_torture_init,
-       .cleanup = NULL,
-       .readlock = sched_torture_read_lock,
-       .readdelay = rcu_read_delay,  /* just reuse rcu's version. */
-       .readunlock = sched_torture_read_unlock,
-       .completed = sched_torture_completed,
-       .deferredfree = rcu_sched_torture_deferred_free,
-       .sync = sched_torture_synchronize,
-       .cb_barrier = rcu_barrier_sched,
-       .stats = NULL,
-       .irqcapable = 1,
-       .name = "sched"
+       .init           = rcu_sync_torture_init,
+       .cleanup        = NULL,
+       .readlock       = sched_torture_read_lock,
+       .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
+       .readunlock     = sched_torture_read_unlock,
+       .completed      = rcu_no_completed,
+       .deferred_free  = rcu_sched_torture_deferred_free,
+       .sync           = sched_torture_synchronize,
+       .cb_barrier     = rcu_barrier_sched,
+       .fqs            = rcu_sched_force_quiescent_state,
+       .stats          = NULL,
+       .irq_capable    = 1,
+       .name           = "sched"
+};
+
+static struct rcu_torture_ops sched_sync_ops = {
+       .init           = rcu_sync_torture_init,
+       .cleanup        = NULL,
+       .readlock       = sched_torture_read_lock,
+       .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
+       .readunlock     = sched_torture_read_unlock,
+       .completed      = rcu_no_completed,
+       .deferred_free  = rcu_sync_torture_deferred_free,
+       .sync           = sched_torture_synchronize,
+       .cb_barrier     = NULL,
+       .fqs            = rcu_sched_force_quiescent_state,
+       .stats          = NULL,
+       .name           = "sched_sync"
 };
 
-static struct rcu_torture_ops sched_ops_sync = {
-       .init = rcu_sync_torture_init,
-       .cleanup = NULL,
-       .readlock = sched_torture_read_lock,
-       .readdelay = rcu_read_delay,  /* just reuse rcu's version. */
-       .readunlock = sched_torture_read_unlock,
-       .completed = sched_torture_completed,
-       .deferredfree = rcu_sync_torture_deferred_free,
-       .sync = sched_torture_synchronize,
-       .cb_barrier = NULL,
-       .stats = NULL,
-       .name = "sched_sync"
+static struct rcu_torture_ops sched_expedited_ops = {
+       .init           = rcu_sync_torture_init,
+       .cleanup        = NULL,
+       .readlock       = sched_torture_read_lock,
+       .read_delay     = rcu_read_delay,  /* just reuse rcu's version. */
+       .readunlock     = sched_torture_read_unlock,
+       .completed      = rcu_no_completed,
+       .deferred_free  = rcu_sync_torture_deferred_free,
+       .sync           = synchronize_sched_expedited,
+       .cb_barrier     = NULL,
+       .fqs            = rcu_sched_force_quiescent_state,
+       .stats          = NULL,
+       .irq_capable    = 1,
+       .name           = "sched_expedited"
 };
 
 /*
+ * RCU torture force-quiescent-state kthread.  Repeatedly induces
+ * bursts of calls to force_quiescent_state(), increasing the probability
+ * of occurrence of some important types of race conditions.
+ */
+static int
+rcu_torture_fqs(void *arg)
+{
+       unsigned long fqs_resume_time;
+       int fqs_burst_remaining;
+
+       VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
+       do {
+               fqs_resume_time = jiffies + fqs_stutter * HZ;
+               while (jiffies - fqs_resume_time > LONG_MAX) {
+                       schedule_timeout_interruptible(1);
+               }
+               fqs_burst_remaining = fqs_duration;
+               while (fqs_burst_remaining > 0) {
+                       cur_ops->fqs();
+                       udelay(fqs_holdoff);
+                       fqs_burst_remaining -= fqs_holdoff;
+               }
+               rcu_stutter_wait("rcu_torture_fqs");
+       } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
+       VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
+       rcutorture_shutdown_absorb("rcu_torture_fqs");
+       while (!kthread_should_stop())
+               schedule_timeout_uninterruptible(1);
+       return 0;
+}
+
+/*
  * RCU torture writer kthread.  Repeatedly substitutes a new structure
  * for that pointed to by rcu_torture_current, freeing the old structure
  * after a series of grace periods (the "pipeline").
@@ -603,28 +727,30 @@ rcu_torture_writer(void *arg)
 
        do {
                schedule_timeout_uninterruptible(1);
-               if ((rp = rcu_torture_alloc()) == NULL)
+               rp = rcu_torture_alloc();
+               if (rp == NULL)
                        continue;
                rp->rtort_pipe_count = 0;
                udelay(rcu_random(&rand) & 0x3ff);
                old_rp = rcu_torture_current;
                rp->rtort_mbtest = 1;
                rcu_assign_pointer(rcu_torture_current, rp);
-               smp_wmb();
+               smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
                if (old_rp) {
                        i = old_rp->rtort_pipe_count;
                        if (i > RCU_TORTURE_PIPE_LEN)
                                i = RCU_TORTURE_PIPE_LEN;
                        atomic_inc(&rcu_torture_wcount[i]);
                        old_rp->rtort_pipe_count++;
-                       cur_ops->deferredfree(old_rp);
+                       cur_ops->deferred_free(old_rp);
                }
                rcu_torture_current_version++;
                oldbatch = cur_ops->completed();
-               rcu_stutter_wait();
-       } while (!kthread_should_stop() && !fullstop);
+               rcu_stutter_wait("rcu_torture_writer");
+       } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
        VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
-       while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+       rcutorture_shutdown_absorb("rcu_torture_writer");
+       while (!kthread_should_stop())
                schedule_timeout_uninterruptible(1);
        return 0;
 }
@@ -645,11 +771,12 @@ rcu_torture_fakewriter(void *arg)
                schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
                udelay(rcu_random(&rand) & 0x3ff);
                cur_ops->sync();
-               rcu_stutter_wait();
-       } while (!kthread_should_stop() && !fullstop);
+               rcu_stutter_wait("rcu_torture_fakewriter");
+       } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
 
        VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
-       while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+       rcutorture_shutdown_absorb("rcu_torture_fakewriter");
+       while (!kthread_should_stop())
                schedule_timeout_uninterruptible(1);
        return 0;
 }
@@ -671,7 +798,11 @@ static void rcu_torture_timer(unsigned long unused)
 
        idx = cur_ops->readlock();
        completed = cur_ops->completed();
-       p = rcu_dereference(rcu_torture_current);
+       p = rcu_dereference_check(rcu_torture_current,
+                                 rcu_read_lock_held() ||
+                                 rcu_read_lock_bh_held() ||
+                                 rcu_read_lock_sched_held() ||
+                                 srcu_read_lock_held(&srcu_ctl));
        if (p == NULL) {
                /* Leave because rcu_torture_writer is not yet underway */
                cur_ops->readunlock(idx);
@@ -680,7 +811,7 @@ static void rcu_torture_timer(unsigned long unused)
        if (p->rtort_mbtest == 0)
                atomic_inc(&n_rcu_torture_mberror);
        spin_lock(&rand_lock);
-       cur_ops->readdelay(&rand);
+       cur_ops->read_delay(&rand);
        n_rcu_torture_timers++;
        spin_unlock(&rand_lock);
        preempt_disable();
@@ -689,13 +820,13 @@ static void rcu_torture_timer(unsigned long unused)
                /* Should not happen, but... */
                pipe_count = RCU_TORTURE_PIPE_LEN;
        }
-       ++__get_cpu_var(rcu_torture_count)[pipe_count];
+       __this_cpu_inc(rcu_torture_count[pipe_count]);
        completed = cur_ops->completed() - completed;
        if (completed > RCU_TORTURE_PIPE_LEN) {
                /* Should not happen, but... */
                completed = RCU_TORTURE_PIPE_LEN;
        }
-       ++__get_cpu_var(rcu_torture_batch)[completed];
+       __this_cpu_inc(rcu_torture_batch[completed]);
        preempt_enable();
        cur_ops->readunlock(idx);
 }
@@ -718,17 +849,21 @@ rcu_torture_reader(void *arg)
 
        VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
        set_user_nice(current, 19);
-       if (irqreader && cur_ops->irqcapable)
+       if (irqreader && cur_ops->irq_capable)
                setup_timer_on_stack(&t, rcu_torture_timer, 0);
 
        do {
-               if (irqreader && cur_ops->irqcapable) {
+               if (irqreader && cur_ops->irq_capable) {
                        if (!timer_pending(&t))
-                               mod_timer(&t, 1);
+                               mod_timer(&t, jiffies + 1);
                }
                idx = cur_ops->readlock();
                completed = cur_ops->completed();
-               p = rcu_dereference(rcu_torture_current);
+               p = rcu_dereference_check(rcu_torture_current,
+                                         rcu_read_lock_held() ||
+                                         rcu_read_lock_bh_held() ||
+                                         rcu_read_lock_sched_held() ||
+                                         srcu_read_lock_held(&srcu_ctl));
                if (p == NULL) {
                        /* Wait for rcu_torture_writer to get underway */
                        cur_ops->readunlock(idx);
@@ -737,29 +872,30 @@ rcu_torture_reader(void *arg)
                }
                if (p->rtort_mbtest == 0)
                        atomic_inc(&n_rcu_torture_mberror);
-               cur_ops->readdelay(&rand);
+               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;
                }
-               ++__get_cpu_var(rcu_torture_count)[pipe_count];
+               __this_cpu_inc(rcu_torture_count[pipe_count]);
                completed = cur_ops->completed() - completed;
                if (completed > RCU_TORTURE_PIPE_LEN) {
                        /* Should not happen, but... */
                        completed = RCU_TORTURE_PIPE_LEN;
                }
-               ++__get_cpu_var(rcu_torture_batch)[completed];
+               __this_cpu_inc(rcu_torture_batch[completed]);
                preempt_enable();
                cur_ops->readunlock(idx);
                schedule();
-               rcu_stutter_wait();
-       } while (!kthread_should_stop() && !fullstop);
+               rcu_stutter_wait("rcu_torture_reader");
+       } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
        VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
-       if (irqreader && cur_ops->irqcapable)
+       rcutorture_shutdown_absorb("rcu_torture_reader");
+       if (irqreader && cur_ops->irq_capable)
                del_timer_sync(&t);
-       while (!kthread_should_stop() && fullstop != FULLSTOP_SIGNALED)
+       while (!kthread_should_stop())
                schedule_timeout_uninterruptible(1);
        return 0;
 }
@@ -856,7 +992,8 @@ rcu_torture_stats(void *arg)
        do {
                schedule_timeout_interruptible(stat_interval * HZ);
                rcu_torture_stats_print();
-       } while (!kthread_should_stop() && !fullstop);
+               rcutorture_shutdown_absorb("rcu_torture_stats");
+       } while (!kthread_should_stop());
        VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
        return 0;
 }
@@ -868,52 +1005,48 @@ static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
  */
 static void rcu_torture_shuffle_tasks(void)
 {
-       cpumask_var_t tmp_mask;
        int i;
 
-       if (!alloc_cpumask_var(&tmp_mask, GFP_KERNEL))
-               BUG();
-
-       cpumask_setall(tmp_mask);
+       cpumask_setall(shuffle_tmp_mask);
        get_online_cpus();
 
        /* No point in shuffling if there is only one online CPU (ex: UP) */
-       if (num_online_cpus() == 1)
-               goto out;
+       if (num_online_cpus() == 1) {
+               put_online_cpus();
+               return;
+       }
 
        if (rcu_idle_cpu != -1)
-               cpumask_clear_cpu(rcu_idle_cpu, tmp_mask);
+               cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
 
-       set_cpus_allowed_ptr(current, tmp_mask);
+       set_cpus_allowed_ptr(current, shuffle_tmp_mask);
 
        if (reader_tasks) {
                for (i = 0; i < nrealreaders; i++)
                        if (reader_tasks[i])
                                set_cpus_allowed_ptr(reader_tasks[i],
-                                                    tmp_mask);
+                                                    shuffle_tmp_mask);
        }
 
        if (fakewriter_tasks) {
                for (i = 0; i < nfakewriters; i++)
                        if (fakewriter_tasks[i])
                                set_cpus_allowed_ptr(fakewriter_tasks[i],
-                                                    tmp_mask);
+                                                    shuffle_tmp_mask);
        }
 
        if (writer_task)
-               set_cpus_allowed_ptr(writer_task, tmp_mask);
+               set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
 
        if (stats_task)
-               set_cpus_allowed_ptr(stats_task, tmp_mask);
+               set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
 
        if (rcu_idle_cpu == -1)
                rcu_idle_cpu = num_online_cpus() - 1;
        else
                rcu_idle_cpu--;
 
-out:
        put_online_cpus();
-       free_cpumask_var(tmp_mask);
 }
 
 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
@@ -927,7 +1060,8 @@ rcu_torture_shuffle(void *arg)
        do {
                schedule_timeout_interruptible(shuffle_interval * HZ);
                rcu_torture_shuffle_tasks();
-       } while (!kthread_should_stop() && !fullstop);
+               rcutorture_shutdown_absorb("rcu_torture_shuffle");
+       } while (!kthread_should_stop());
        VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
        return 0;
 }
@@ -942,10 +1076,11 @@ rcu_torture_stutter(void *arg)
        do {
                schedule_timeout_interruptible(stutter * HZ);
                stutter_pause_test = 1;
-               if (!kthread_should_stop() && !fullstop)
+               if (!kthread_should_stop())
                        schedule_timeout_interruptible(stutter * HZ);
                stutter_pause_test = 0;
-       } while (!kthread_should_stop() && !fullstop);
+               rcutorture_shutdown_absorb("rcu_torture_stutter");
+       } while (!kthread_should_stop());
        VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
        return 0;
 }
@@ -956,10 +1091,11 @@ rcu_torture_print_module_parms(char *tag)
        printk(KERN_ALERT "%s" TORTURE_FLAG
                "--- %s: nreaders=%d nfakewriters=%d "
                "stat_interval=%d verbose=%d test_no_idle_hz=%d "
-               "shuffle_interval=%d stutter=%d irqreader=%d\n",
+               "shuffle_interval=%d stutter=%d irqreader=%d "
+               "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d\n",
                torture_type, tag, nrealreaders, nfakewriters,
                stat_interval, verbose, test_no_idle_hz, shuffle_interval,
-               stutter, irqreader);
+               stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter);
 }
 
 static struct notifier_block rcutorture_nb = {
@@ -972,15 +1108,16 @@ rcu_torture_cleanup(void)
        int i;
 
        mutex_lock(&fullstop_mutex);
-       if (!fullstop) {
-               /* If being signaled, let it happen, then exit. */
+       if (fullstop == FULLSTOP_SHUTDOWN) {
+               printk(KERN_WARNING /* but going down anyway, so... */
+                      "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
                mutex_unlock(&fullstop_mutex);
-               schedule_timeout_interruptible(10 * HZ);
+               schedule_timeout_uninterruptible(10);
                if (cur_ops->cb_barrier != NULL)
                        cur_ops->cb_barrier();
                return;
        }
-       fullstop = FULLSTOP_CLEANUP;
+       fullstop = FULLSTOP_RMMOD;
        mutex_unlock(&fullstop_mutex);
        unregister_reboot_notifier(&rcutorture_nb);
        if (stutter_task) {
@@ -991,6 +1128,7 @@ rcu_torture_cleanup(void)
        if (shuffler_task) {
                VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
                kthread_stop(shuffler_task);
+               free_cpumask_var(shuffle_tmp_mask);
        }
        shuffler_task = NULL;
 
@@ -1033,6 +1171,12 @@ rcu_torture_cleanup(void)
        }
        stats_task = NULL;
 
+       if (fqs_task) {
+               VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
+               kthread_stop(fqs_task);
+       }
+       fqs_task = NULL;
+
        /* Wait for all RCU callbacks to fire.  */
 
        if (cur_ops->cb_barrier != NULL)
@@ -1055,8 +1199,10 @@ rcu_torture_init(void)
        int cpu;
        int firsterr = 0;
        static struct rcu_torture_ops *torture_ops[] =
-               { &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
-                 &srcu_ops, &sched_ops, &sched_ops_sync, };
+               { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops,
+                 &rcu_bh_ops, &rcu_bh_sync_ops,
+                 &srcu_ops, &srcu_expedited_ops,
+                 &sched_ops, &sched_sync_ops, &sched_expedited_ops, };
 
        mutex_lock(&fullstop_mutex);
 
@@ -1067,10 +1213,19 @@ rcu_torture_init(void)
                        break;
        }
        if (i == ARRAY_SIZE(torture_ops)) {
-               printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
+               printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n",
                       torture_type);
+               printk(KERN_ALERT "rcu-torture types:");
+               for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
+                       printk(KERN_ALERT " %s", torture_ops[i]->name);
+               printk(KERN_ALERT "\n");
                mutex_unlock(&fullstop_mutex);
-               return (-EINVAL);
+               return -EINVAL;
+       }
+       if (cur_ops->fqs == NULL && fqs_duration != 0) {
+               printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero "
+                                 "fqs_duration, fqs disabled.\n");
+               fqs_duration = 0;
        }
        if (cur_ops->init)
                cur_ops->init(); /* no "goto unwind" prior to this point!!! */
@@ -1080,7 +1235,7 @@ rcu_torture_init(void)
        else
                nrealreaders = 2 * num_online_cpus();
        rcu_torture_print_module_parms("Start of test");
-       fullstop = 0;
+       fullstop = FULLSTOP_DONTSTOP;
 
        /* Set up the freelist. */
 
@@ -1121,7 +1276,7 @@ rcu_torture_init(void)
                goto unwind;
        }
        fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
-                                  GFP_KERNEL);
+                                  GFP_KERNEL);
        if (fakewriter_tasks == NULL) {
                VERBOSE_PRINTK_ERRSTRING("out of memory");
                firsterr = -ENOMEM;
@@ -1130,7 +1285,7 @@ rcu_torture_init(void)
        for (i = 0; i < nfakewriters; i++) {
                VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
                fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
-                                                 "rcu_torture_fakewriter");
+                                                 "rcu_torture_fakewriter");
                if (IS_ERR(fakewriter_tasks[i])) {
                        firsterr = PTR_ERR(fakewriter_tasks[i]);
                        VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
@@ -1169,10 +1324,18 @@ rcu_torture_init(void)
        }
        if (test_no_idle_hz) {
                rcu_idle_cpu = num_online_cpus() - 1;
+
+               if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
+                       firsterr = -ENOMEM;
+                       VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
+                       goto unwind;
+               }
+
                /* Create the shuffler thread */
                shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
                                          "rcu_torture_shuffle");
                if (IS_ERR(shuffler_task)) {
+                       free_cpumask_var(shuffle_tmp_mask);
                        firsterr = PTR_ERR(shuffler_task);
                        VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
                        shuffler_task = NULL;
@@ -1192,6 +1355,19 @@ rcu_torture_init(void)
                        goto unwind;
                }
        }
+       if (fqs_duration < 0)
+               fqs_duration = 0;
+       if (fqs_duration) {
+               /* Create the stutter thread */
+               fqs_task = kthread_run(rcu_torture_fqs, NULL,
+                                      "rcu_torture_fqs");
+               if (IS_ERR(fqs_task)) {
+                       firsterr = PTR_ERR(fqs_task);
+                       VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
+                       fqs_task = NULL;
+                       goto unwind;
+               }
+       }
        register_reboot_notifier(&rcutorture_nb);
        mutex_unlock(&fullstop_mutex);
        return 0;