[PATCH] rcutorture: add ops vector and Classic RCU ops

Add an ops vector to rcutorture, and add the ops for Classic RCU.  Update
the rcutorture documentation to reflect slight change to the dmesg formats.

Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 120 insertions, 43 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 2a65bd8a3d10..c96b5edd6ed1 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -53,6 +53,7 @@ static int stat_interval;	/* Interval between stats, in seconds. */
 static int verbose;             /* Print more debug info. */
 static int test_no_idle_hz;     /* Test RCU's support for tickless idle CPUs. */
 static int shuffle_interval = 5; /* Interval between shuffles (in sec)*/
+static char *torture_type = "rcu"; /* What to torture. */
 
 module_param(nreaders, int, 0);
 MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
@@ -64,13 +65,16 @@ module_param(test_no_idle_hz, bool, 0);
 MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
 module_param(shuffle_interval, int, 0);
 MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
-#define TORTURE_FLAG "rcutorture: "
+module_param(torture_type, charp, 0);
+MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu)");
+
+#define TORTURE_FLAG "-torture:"
 #define PRINTK_STRING(s) \
-        do { printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0)
+        do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
 #define VERBOSE_PRINTK_STRING(s) \
-        do { if (verbose) printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0)
+        do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
 #define VERBOSE_PRINTK_ERRSTRING(s) \
-        do { if (verbose) printk(KERN_ALERT TORTURE_FLAG "!!! " s "\n"); } while (0)
+        do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
 
 static char printk_buf[4096];
 
@@ -139,28 +143,6 @@ rcu_torture_free(struct rcu_torture *p)
         spin_unlock_bh(&rcu_torture_lock);
 }
 
-static void
-rcu_torture_cb(struct rcu_head *p)
-{
-        int i;
-        struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
-
-        if (fullstop) {
-                /* Test is ending, just drop callbacks on the floor. */
-                /* The next initialization will pick up the pieces. */
-                return;
-        }
-        i = rp->rtort_pipe_count;
-        if (i > RCU_TORTURE_PIPE_LEN)
-                i = RCU_TORTURE_PIPE_LEN;
-        atomic_inc(&rcu_torture_wcount[i]);
-        if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
-                rp->rtort_mbtest = 0;
-                rcu_torture_free(rp);
-        } else
-                call_rcu(p, rcu_torture_cb);
-}
-
 struct rcu_random_state {
         unsigned long rrs_state;
         unsigned long rrs_count;
@@ -191,6 +173,83 @@ rcu_random(struct rcu_random_state *rrsp)
 }
 
 /*
+ * Operations vector for selecting different types of tests.
+ */
+
+struct rcu_torture_ops {
+        void (*init)(void);
+        void (*cleanup)(void);
+        int (*readlock)(void);
+        void (*readunlock)(int idx);
+        int (*completed)(void);
+        void (*deferredfree)(struct rcu_torture *p);
+        int (*stats)(char *page);
+        char *name;
+};
+static struct rcu_torture_ops *cur_ops = NULL;
+
+/*
+ * Definitions for rcu torture testing.
+ */
+
+static int rcu_torture_read_lock(void)
+{
+        rcu_read_lock();
+        return 0;
+}
+
+static void rcu_torture_read_unlock(int idx)
+{
+        rcu_read_unlock();
+}
+
+static int rcu_torture_completed(void)
+{
+        return rcu_batches_completed();
+}
+
+static void
+rcu_torture_cb(struct rcu_head *p)
+{
+        int i;
+        struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
+
+        if (fullstop) {
+                /* Test is ending, just drop callbacks on the floor. */
+                /* The next initialization will pick up the pieces. */
+                return;
+        }
+        i = rp->rtort_pipe_count;
+        if (i > RCU_TORTURE_PIPE_LEN)
+                i = RCU_TORTURE_PIPE_LEN;
+        atomic_inc(&rcu_torture_wcount[i]);
+        if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
+                rp->rtort_mbtest = 0;
+                rcu_torture_free(rp);
+        } else
+                cur_ops->deferredfree(rp);
+}
+
+static void rcu_torture_deferred_free(struct rcu_torture *p)
+{
+        call_rcu(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static struct rcu_torture_ops rcu_ops = {
+        .init = NULL,
+        .cleanup = NULL,
+        .readlock = rcu_torture_read_lock,
+        .readunlock = rcu_torture_read_unlock,
+        .completed = rcu_torture_completed,
+        .deferredfree = rcu_torture_deferred_free,
+        .stats = NULL,
+        .name = "rcu"
+};
+
+static struct rcu_torture_ops *torture_ops[] =
+        { &rcu_ops, NULL };
+
+/*
  * 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").
@@ -209,8 +268,6 @@ rcu_torture_writer(void *arg)
 
         do {
                 schedule_timeout_uninterruptible(1);
-                if (rcu_batches_completed() == oldbatch)
-                        continue;
                 if ((rp = rcu_torture_alloc()) == NULL)
                         continue;
                 rp->rtort_pipe_count = 0;
@@ -225,10 +282,10 @@ rcu_torture_writer(void *arg)
                                 i = RCU_TORTURE_PIPE_LEN;
                         atomic_inc(&rcu_torture_wcount[i]);
                         old_rp->rtort_pipe_count++;
-                        call_rcu(&old_rp->rtort_rcu, rcu_torture_cb);
+                        cur_ops->deferredfree(old_rp);
                 }
                 rcu_torture_current_version++;
-                oldbatch = rcu_batches_completed();
+                oldbatch = cur_ops->completed();
         } while (!kthread_should_stop() && !fullstop);
         VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
         while (!kthread_should_stop())
@@ -246,6 +303,7 @@ static int
 rcu_torture_reader(void *arg)
 {
         int completed;
+        int idx;
         DEFINE_RCU_RANDOM(rand);
         struct rcu_torture *p;
         int pipe_count;
@@ -254,12 +312,12 @@ rcu_torture_reader(void *arg)
         set_user_nice(current, 19);
 
         do {
-                rcu_read_lock();
-                completed = rcu_batches_completed();
+                idx = cur_ops->readlock();
+                completed = cur_ops->completed();
                 p = rcu_dereference(rcu_torture_current);
                 if (p == NULL) {
                         /* Wait for rcu_torture_writer to get underway */
-                        rcu_read_unlock();
+                        cur_ops->readunlock(idx);
                         schedule_timeout_interruptible(HZ);
                         continue;
                 }
@@ -273,14 +331,14 @@ rcu_torture_reader(void *arg)
                         pipe_count = RCU_TORTURE_PIPE_LEN;
                 }
                 ++__get_cpu_var(rcu_torture_count)[pipe_count];
-                completed = rcu_batches_completed() - completed;
+                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];
                 preempt_enable();
-                rcu_read_unlock();
+                cur_ops->readunlock(idx);
                 schedule();
         } while (!kthread_should_stop() && !fullstop);
         VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
@@ -311,7 +369,7 @@ rcu_torture_printk(char *page)
                 if (pipesummary[i] != 0)
                         break;
         }
-        cnt += sprintf(&page[cnt], "rcutorture: ");
+        cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
         cnt += sprintf(&page[cnt],
                        "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
                        "rtmbe: %d",
@@ -324,7 +382,7 @@ rcu_torture_printk(char *page)
                        atomic_read(&n_rcu_torture_mberror));
         if (atomic_read(&n_rcu_torture_mberror) != 0)
                 cnt += sprintf(&page[cnt], " !!!");
-        cnt += sprintf(&page[cnt], "\nrcutorture: ");
+        cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
         if (i > 1) {
                 cnt += sprintf(&page[cnt], "!!! ");
                 atomic_inc(&n_rcu_torture_error);
@@ -332,17 +390,19 @@ rcu_torture_printk(char *page)
         cnt += sprintf(&page[cnt], "Reader Pipe: ");
         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
                 cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
-        cnt += sprintf(&page[cnt], "\nrcutorture: ");
+        cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
         cnt += sprintf(&page[cnt], "Reader Batch: ");
-        for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++)
+        for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
                 cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
-        cnt += sprintf(&page[cnt], "\nrcutorture: ");
+        cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
         cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
                 cnt += sprintf(&page[cnt], " %d",
                                atomic_read(&rcu_torture_wcount[i]));
         }
         cnt += sprintf(&page[cnt], "\n");
+        if (cur_ops->stats != NULL)
+                cnt += cur_ops->stats(&page[cnt]);
         return cnt;
 }
 
@@ -444,11 +504,11 @@ rcu_torture_shuffle(void *arg)
 static inline void
 rcu_torture_print_module_parms(char *tag)
 {
-        printk(KERN_ALERT TORTURE_FLAG "--- %s: nreaders=%d "
+        printk(KERN_ALERT "%s" TORTURE_FLAG "--- %s: nreaders=%d "
                 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
                 "shuffle_interval = %d\n",
-                tag, nrealreaders, stat_interval, verbose, test_no_idle_hz,
-                shuffle_interval);
+                torture_type, tag, nrealreaders, stat_interval, verbose,
+                test_no_idle_hz, shuffle_interval);
 }
 
 static void
@@ -493,6 +553,9 @@ rcu_torture_cleanup(void)
         rcu_barrier();
 
         rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
+
+        if (cur_ops->cleanup != NULL)
+                cur_ops->cleanup();
         if (atomic_read(&n_rcu_torture_error))
                 rcu_torture_print_module_parms("End of test: FAILURE");
         else
@@ -508,6 +571,20 @@ rcu_torture_init(void)
 
         /* Process args and tell the world that the torturer is on the job. */
 
+        for (i = 0; cur_ops = torture_ops[i], cur_ops != NULL; i++) {
+                cur_ops = torture_ops[i];
+                if (strcmp(torture_type, cur_ops->name) == 0) {
+                        break;
+                }
+        }
+        if (cur_ops == NULL) {
+                printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
+                       torture_type);
+                return (-EINVAL);
+        }
+        if (cur_ops->init != NULL)
+                cur_ops->init(); /* no "goto unwind" prior to this point!!! */
+
         if (nreaders >= 0)
                 nrealreaders = nreaders;
         else