1 files changed, 43 insertions, 23 deletions

diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
index 29dc253d03af..bcb1b9fea588 100644
--- a/kernel/locking/test-ww_mutex.c
+++ b/kernel/locking/test-ww_mutex.c
@@ -9,7 +9,7 @@
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
-#include <linux/random.h>
+#include <linux/prandom.h>
 #include <linux/slab.h>
 #include <linux/ww_mutex.h>
 
@@ -62,7 +62,8 @@ static int __test_mutex(unsigned int flags)
 	int ret;
 
 	ww_mutex_init(&mtx.mutex, &ww_class);
-	ww_acquire_init(&ctx, &ww_class);
+	if (flags & TEST_MTX_CTX)
+		ww_acquire_init(&ctx, &ww_class);
 
 	INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
 	init_completion(&mtx.ready);
@@ -90,7 +91,8 @@ static int __test_mutex(unsigned int flags)
 		ret = wait_for_completion_timeout(&mtx.done, TIMEOUT);
 	}
 	ww_mutex_unlock(&mtx.mutex);
-	ww_acquire_fini(&ctx);
+	if (flags & TEST_MTX_CTX)
+		ww_acquire_fini(&ctx);
 
 	if (ret) {
 		pr_err("%s(flags=%x): mutual exclusion failure\n",
@@ -386,10 +388,23 @@ struct stress {
 	int nlocks;
 };
 
+struct rnd_state rng;
+DEFINE_SPINLOCK(rng_lock);
+
+static inline u32 prandom_u32_below(u32 ceil)
+{
+	u32 ret;
+
+	spin_lock(&rng_lock);
+	ret = prandom_u32_state(&rng) % ceil;
+	spin_unlock(&rng_lock);
+	return ret;
+}
+
 static int *get_random_order(int count)
 {
 	int *order;
-	int n, r, tmp;
+	int n, r;
 
 	order = kmalloc_array(count, sizeof(*order), GFP_KERNEL);
 	if (!order)
@@ -399,12 +414,9 @@ static int *get_random_order(int count)
 		order[n] = n;
 
 	for (n = count - 1; n > 1; n--) {
-		r = get_random_u32_below(n + 1);
-		if (r != n) {
-			tmp = order[n];
-			order[n] = order[r];
-			order[r] = tmp;
-		}
+		r = prandom_u32_below(n + 1);
+		if (r != n)
+			swap(order[n], order[r]);
 	}
 
 	return order;
@@ -452,21 +464,21 @@ retry:
 			ww_mutex_unlock(&locks[order[n]]);
 
 		if (err == -EDEADLK) {
-			ww_mutex_lock_slow(&locks[order[contended]], &ctx);
-			goto retry;
+			if (!time_after(jiffies, stress->timeout)) {
+				ww_mutex_lock_slow(&locks[order[contended]], &ctx);
+				goto retry;
+			}
 		}
 
+		ww_acquire_fini(&ctx);
 		if (err) {
 			pr_err_once("stress (%s) failed with %d\n",
 				    __func__, err);
 			break;
 		}
-
-		ww_acquire_fini(&ctx);
 	} while (!time_after(jiffies, stress->timeout));
 
 	kfree(order);
-	kfree(stress);
 }
 
 struct reorder_lock {
@@ -531,7 +543,6 @@ out:
 	list_for_each_entry_safe(ll, ln, &locks, link)
 		kfree(ll);
 	kfree(order);
-	kfree(stress);
 }
 
 static void stress_one_work(struct work_struct *work)
@@ -552,8 +563,6 @@ static void stress_one_work(struct work_struct *work)
 			break;
 		}
 	} while (!time_after(jiffies, stress->timeout));
-
-	kfree(stress);
 }
 
 #define STRESS_INORDER BIT(0)
@@ -564,15 +573,24 @@ static void stress_one_work(struct work_struct *work)
 static int stress(int nlocks, int nthreads, unsigned int flags)
 {
 	struct ww_mutex *locks;
-	int n;
+	struct stress *stress_array;
+	int n, count;
 
 	locks = kmalloc_array(nlocks, sizeof(*locks), GFP_KERNEL);
 	if (!locks)
 		return -ENOMEM;
 
+	stress_array = kmalloc_array(nthreads, sizeof(*stress_array),
+				     GFP_KERNEL);
+	if (!stress_array) {
+		kfree(locks);
+		return -ENOMEM;
+	}
+
 	for (n = 0; n < nlocks; n++)
 		ww_mutex_init(&locks[n], &ww_class);
 
+	count = 0;
 	for (n = 0; nthreads; n++) {
 		struct stress *stress;
 		void (*fn)(struct work_struct *work);
@@ -596,9 +614,7 @@ static int stress(int nlocks, int nthreads, unsigned int flags)
 		if (!fn)
 			continue;
 
-		stress = kmalloc(sizeof(*stress), GFP_KERNEL);
-		if (!stress)
-			break;
+		stress = &stress_array[count++];
 
 		INIT_WORK(&stress->work, fn);
 		stress->locks = locks;
@@ -613,6 +629,7 @@ static int stress(int nlocks, int nthreads, unsigned int flags)
 
 	for (n = 0; n < nlocks; n++)
 		ww_mutex_destroy(&locks[n]);
+	kfree(stress_array);
 	kfree(locks);
 
 	return 0;
@@ -625,6 +642,8 @@ static int __init test_ww_mutex_init(void)
 
 	printk(KERN_INFO "Beginning ww mutex selftests\n");
 
+	prandom_seed_state(&rng, get_random_u64());
+
 	wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0);
 	if (!wq)
 		return -ENOMEM;
@@ -659,7 +678,7 @@ static int __init test_ww_mutex_init(void)
 	if (ret)
 		return ret;
 
-	ret = stress(4095, hweight32(STRESS_ALL)*ncpus, STRESS_ALL);
+	ret = stress(2046, hweight32(STRESS_ALL)*ncpus, STRESS_ALL);
 	if (ret)
 		return ret;
 
@@ -677,3 +696,4 @@ module_exit(test_ww_mutex_exit);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("API test facility for ww_mutexes");