manual update from upstream:

Applied Al's change 06a544971fad0992fe8b92c5647538d573089dd4
to new location of swiotlb.c

Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 492 insertions, 0 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
new file mode 100644
index 00000000000..9b58f1eff3c
--- /dev/null
+++ b/kernel/rcutorture.c
@@ -0,0 +1,492 @@
+/*
+ * Read-Copy Update /proc-based torture test facility
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2005
+ *
+ * Authors: Paul E. McKenney <paulmck@us.ibm.com>
+ *
+ * See also:  Documentation/RCU/torture.txt
+ */
+#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/smp.h>
+#include <linux/rcupdate.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <asm/atomic.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/rcuref.h>
+#include <linux/cpu.h>
+#include <linux/random.h>
+#include <linux/delay.h>
+#include <linux/byteorder/swabb.h>
+#include <linux/stat.h>
+
+MODULE_LICENSE("GPL");
+
+static int nreaders = -1;	/* # reader threads, defaults to 4*ncpus */
+static int stat_interval = 0;	/* Interval between stats, in seconds. */
+				/*  Defaults to "only at end of test". */
+static int verbose = 0;		/* Print more debug info. */
+
+MODULE_PARM(nreaders, "i");
+MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
+MODULE_PARM(stat_interval, "i");
+MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
+MODULE_PARM(verbose, "i");
+MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
+#define TORTURE_FLAG "rcutorture: "
+#define PRINTK_STRING(s) \
+	do { printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0)
+#define VERBOSE_PRINTK_STRING(s) \
+	do { if (verbose) printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0)
+#define VERBOSE_PRINTK_ERRSTRING(s) \
+	do { if (verbose) printk(KERN_ALERT TORTURE_FLAG "!!! " s "\n"); } while (0)
+
+static char printk_buf[4096];
+
+static int nrealreaders;
+static struct task_struct *writer_task;
+static struct task_struct **reader_tasks;
+static struct task_struct *stats_task;
+
+#define RCU_TORTURE_PIPE_LEN 10
+
+struct rcu_torture {
+	struct rcu_head rtort_rcu;
+	int rtort_pipe_count;
+	struct list_head rtort_free;
+};
+
+static int fullstop = 0;	/* stop generating callbacks at test end. */
+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_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) =
+	{ 0 };
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
+	{ 0 };
+static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
+atomic_t n_rcu_torture_alloc;
+atomic_t n_rcu_torture_alloc_fail;
+atomic_t n_rcu_torture_free;
+
+/*
+ * Allocate an element from the rcu_tortures pool.
+ */
+struct rcu_torture *
+rcu_torture_alloc(void)
+{
+	struct list_head *p;
+
+	spin_lock(&rcu_torture_lock);
+	if (list_empty(&rcu_torture_freelist)) {
+		atomic_inc(&n_rcu_torture_alloc_fail);
+		spin_unlock(&rcu_torture_lock);
+		return NULL;
+	}
+	atomic_inc(&n_rcu_torture_alloc);
+	p = rcu_torture_freelist.next;
+	list_del_init(p);
+	spin_unlock(&rcu_torture_lock);
+	return container_of(p, struct rcu_torture, rtort_free);
+}
+
+/*
+ * Free an element to the rcu_tortures pool.
+ */
+static void
+rcu_torture_free(struct rcu_torture *p)
+{
+	atomic_inc(&n_rcu_torture_free);
+	spin_lock(&rcu_torture_lock);
+	list_add_tail(&p->rtort_free, &rcu_torture_freelist);
+	spin_unlock(&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)
+		rcu_torture_free(rp);
+	else
+		call_rcu(p, rcu_torture_cb);
+}
+
+struct rcu_random_state {
+	unsigned long rrs_state;
+	unsigned long rrs_count;
+};
+
+#define RCU_RANDOM_MULT 39916801  /* prime */
+#define RCU_RANDOM_ADD	479001701 /* prime */
+#define RCU_RANDOM_REFRESH 10000
+
+#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
+
+/*
+ * Crude but fast random-number generator.  Uses a linear congruential
+ * generator, with occasional help from get_random_bytes().
+ */
+static long
+rcu_random(struct rcu_random_state *rrsp)
+{
+	long refresh;
+
+	if (--rrsp->rrs_count < 0) {
+		get_random_bytes(&refresh, sizeof(refresh));
+		rrsp->rrs_state += refresh;
+		rrsp->rrs_count = RCU_RANDOM_REFRESH;
+	}
+	rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
+	return swahw32(rrsp->rrs_state);
+}
+
+/*
+ * 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").
+ */
+static int
+rcu_torture_writer(void *arg)
+{
+	int i;
+	long oldbatch = rcu_batches_completed();
+	struct rcu_torture *rp;
+	struct rcu_torture *old_rp;
+	static DEFINE_RCU_RANDOM(rand);
+
+	VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
+	do {
+		schedule_timeout_uninterruptible(1);
+		if (rcu_batches_completed() == oldbatch)
+			continue;
+		if ((rp = rcu_torture_alloc()) == NULL)
+			continue;
+		rp->rtort_pipe_count = 0;
+		udelay(rcu_random(&rand) & 0x3ff);
+		old_rp = rcu_torture_current;
+		rcu_assign_pointer(rcu_torture_current, rp);
+		smp_wmb();
+		if (old_rp != NULL) {
+			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++;
+			call_rcu(&old_rp->rtort_rcu, rcu_torture_cb);
+		}
+		rcu_torture_current_version++;
+		oldbatch = rcu_batches_completed();
+	} while (!kthread_should_stop() && !fullstop);
+	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
+	while (!kthread_should_stop())
+		schedule_timeout_uninterruptible(1);
+	return 0;
+}
+
+/*
+ * RCU torture reader kthread.  Repeatedly dereferences rcu_torture_current,
+ * incrementing the corresponding element of the pipeline array.  The
+ * counter in the element should never be greater than 1, otherwise, the
+ * RCU implementation is broken.
+ */
+static int
+rcu_torture_reader(void *arg)
+{
+	int completed;
+	DEFINE_RCU_RANDOM(rand);
+	struct rcu_torture *p;
+	int pipe_count;
+
+	VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
+	do {
+		rcu_read_lock();
+		completed = rcu_batches_completed();
+		p = rcu_dereference(rcu_torture_current);
+		if (p == NULL) {
+			/* Wait for rcu_torture_writer to get underway */
+			rcu_read_unlock();
+			schedule_timeout_interruptible(HZ);
+			continue;
+		}
+		udelay(rcu_random(&rand) & 0x7f);
+		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];
+		completed = rcu_batches_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();
+		schedule();
+	} while (!kthread_should_stop() && !fullstop);
+	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
+	while (!kthread_should_stop())
+		schedule_timeout_uninterruptible(1);
+	return 0;
+}
+
+/*
+ * Create an RCU-torture statistics message in the specified buffer.
+ */
+static int
+rcu_torture_printk(char *page)
+{
+	int cnt = 0;
+	int cpu;
+	int i;
+	long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+	long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+
+	for_each_cpu(cpu) {
+		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+			pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
+			batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
+		}
+	}
+	for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
+		if (pipesummary[i] != 0)
+			break;
+	}
+	cnt += sprintf(&page[cnt], "rcutorture: ");
+	cnt += sprintf(&page[cnt],
+		       "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d",
+		       rcu_torture_current,
+		       rcu_torture_current_version,
+		       list_empty(&rcu_torture_freelist),
+		       atomic_read(&n_rcu_torture_alloc),
+		       atomic_read(&n_rcu_torture_alloc_fail),
+		       atomic_read(&n_rcu_torture_free));
+	cnt += sprintf(&page[cnt], "\nrcutorture: ");
+	if (i > 1)
+		cnt += sprintf(&page[cnt], "!!! ");
+	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], "Reader Batch: ");
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++)
+		cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
+	cnt += sprintf(&page[cnt], "\nrcutorture: ");
+	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");
+	return cnt;
+}
+
+/*
+ * Print torture statistics.  Caller must ensure that there is only
+ * one call to this function at a given time!!!  This is normally
+ * accomplished by relying on the module system to only have one copy
+ * of the module loaded, and then by giving the rcu_torture_stats
+ * kthread full control (or the init/cleanup functions when rcu_torture_stats
+ * thread is not running).
+ */
+static void
+rcu_torture_stats_print(void)
+{
+	int cnt;
+
+	cnt = rcu_torture_printk(printk_buf);
+	printk(KERN_ALERT "%s", printk_buf);
+}
+
+/*
+ * Periodically prints torture statistics, if periodic statistics printing
+ * was specified via the stat_interval module parameter.
+ *
+ * No need to worry about fullstop here, since this one doesn't reference
+ * volatile state or register callbacks.
+ */
+static int
+rcu_torture_stats(void *arg)
+{
+	VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
+	do {
+		schedule_timeout_interruptible(stat_interval * HZ);
+		rcu_torture_stats_print();
+	} while (!kthread_should_stop());
+	VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
+	return 0;
+}
+
+static void
+rcu_torture_cleanup(void)
+{
+	int i;
+
+	fullstop = 1;
+	if (writer_task != NULL) {
+		VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
+		kthread_stop(writer_task);
+	}
+	writer_task = NULL;
+
+	if (reader_tasks != NULL) {
+		for (i = 0; i < nrealreaders; i++) {
+			if (reader_tasks[i] != NULL) {
+				VERBOSE_PRINTK_STRING(
+					"Stopping rcu_torture_reader task");
+				kthread_stop(reader_tasks[i]);
+			}
+			reader_tasks[i] = NULL;
+		}
+		kfree(reader_tasks);
+		reader_tasks = NULL;
+	}
+	rcu_torture_current = NULL;
+
+	if (stats_task != NULL) {
+		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
+		kthread_stop(stats_task);
+	}
+	stats_task = NULL;
+
+	/* Wait for all RCU callbacks to fire.  */
+
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++)
+		synchronize_rcu();
+	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
+	PRINTK_STRING("--- End of test");
+}
+
+static int
+rcu_torture_init(void)
+{
+	int i;
+	int cpu;
+	int firsterr = 0;
+
+	/* Process args and tell the world that the torturer is on the job. */
+
+	if (nreaders >= 0)
+		nrealreaders = nreaders;
+	else
+		nrealreaders = 2 * num_online_cpus();
+	printk(KERN_ALERT TORTURE_FLAG
+	       "--- Start of test: nreaders=%d stat_interval=%d verbose=%d\n",
+	       nrealreaders, stat_interval, verbose);
+	fullstop = 0;
+
+	/* Set up the freelist. */
+
+	INIT_LIST_HEAD(&rcu_torture_freelist);
+	for (i = 0; i < sizeof(rcu_tortures) / sizeof(rcu_tortures[0]); i++) {
+		list_add_tail(&rcu_tortures[i].rtort_free,
+			      &rcu_torture_freelist);
+	}
+
+	/* Initialize the statistics so that each run gets its own numbers. */
+
+	rcu_torture_current = NULL;
+	rcu_torture_current_version = 0;
+	atomic_set(&n_rcu_torture_alloc, 0);
+	atomic_set(&n_rcu_torture_alloc_fail, 0);
+	atomic_set(&n_rcu_torture_free, 0);
+	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+		atomic_set(&rcu_torture_wcount[i], 0);
+	for_each_cpu(cpu) {
+		for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+			per_cpu(rcu_torture_count, cpu)[i] = 0;
+			per_cpu(rcu_torture_batch, cpu)[i] = 0;
+		}
+	}
+
+	/* Start up the kthreads. */
+
+	VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
+	writer_task = kthread_run(rcu_torture_writer, NULL,
+				  "rcu_torture_writer");
+	if (IS_ERR(writer_task)) {
+		firsterr = PTR_ERR(writer_task);
+		VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
+		writer_task = NULL;
+		goto unwind;
+	}
+	reader_tasks = kmalloc(nrealreaders * sizeof(reader_tasks[0]),
+			       GFP_KERNEL);
+	if (reader_tasks == NULL) {
+		VERBOSE_PRINTK_ERRSTRING("out of memory");
+		firsterr = -ENOMEM;
+		goto unwind;
+	}
+	for (i = 0; i < nrealreaders; i++) {
+		VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
+		reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
+					      "rcu_torture_reader");
+		if (IS_ERR(reader_tasks[i])) {
+			firsterr = PTR_ERR(reader_tasks[i]);
+			VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
+			reader_tasks[i] = NULL;
+			goto unwind;
+		}
+	}
+	if (stat_interval > 0) {
+		VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
+		stats_task = kthread_run(rcu_torture_stats, NULL,
+					"rcu_torture_stats");
+		if (IS_ERR(stats_task)) {
+			firsterr = PTR_ERR(stats_task);
+			VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
+			stats_task = NULL;
+			goto unwind;
+		}
+	}
+	return 0;
+
+unwind:
+	rcu_torture_cleanup();
+	return firsterr;
+}
+
+module_init(rcu_torture_init);
+module_exit(rcu_torture_cleanup);