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![Chris Wilson](/assets/img/avatar_default.png)
Use a timeout rather than a fixed number of loops to avoid running for very long periods, such as under the kbuilder VMs. Reported-by: kernel test robot <xiaolong.ye@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170310105733.6444-1-chris@chris-wilson.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
645 lines
13 KiB
C
645 lines
13 KiB
C
/*
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* Module-based API test facility for ww_mutexes
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, you can access it online at
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* http://www.gnu.org/licenses/gpl-2.0.html.
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*/
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#include <linux/kernel.h>
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#include <linux/completion.h>
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#include <linux/delay.h>
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#include <linux/kthread.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/slab.h>
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#include <linux/ww_mutex.h>
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static DEFINE_WW_CLASS(ww_class);
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struct workqueue_struct *wq;
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struct test_mutex {
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struct work_struct work;
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struct ww_mutex mutex;
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struct completion ready, go, done;
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unsigned int flags;
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};
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#define TEST_MTX_SPIN BIT(0)
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#define TEST_MTX_TRY BIT(1)
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#define TEST_MTX_CTX BIT(2)
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#define __TEST_MTX_LAST BIT(3)
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static void test_mutex_work(struct work_struct *work)
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{
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struct test_mutex *mtx = container_of(work, typeof(*mtx), work);
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complete(&mtx->ready);
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wait_for_completion(&mtx->go);
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if (mtx->flags & TEST_MTX_TRY) {
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while (!ww_mutex_trylock(&mtx->mutex))
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cond_resched();
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} else {
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ww_mutex_lock(&mtx->mutex, NULL);
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}
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complete(&mtx->done);
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ww_mutex_unlock(&mtx->mutex);
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}
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static int __test_mutex(unsigned int flags)
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{
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#define TIMEOUT (HZ / 16)
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struct test_mutex mtx;
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struct ww_acquire_ctx ctx;
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int ret;
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ww_mutex_init(&mtx.mutex, &ww_class);
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ww_acquire_init(&ctx, &ww_class);
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INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
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init_completion(&mtx.ready);
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init_completion(&mtx.go);
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init_completion(&mtx.done);
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mtx.flags = flags;
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schedule_work(&mtx.work);
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wait_for_completion(&mtx.ready);
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ww_mutex_lock(&mtx.mutex, (flags & TEST_MTX_CTX) ? &ctx : NULL);
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complete(&mtx.go);
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if (flags & TEST_MTX_SPIN) {
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unsigned long timeout = jiffies + TIMEOUT;
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ret = 0;
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do {
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if (completion_done(&mtx.done)) {
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ret = -EINVAL;
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break;
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}
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cond_resched();
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} while (time_before(jiffies, timeout));
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} else {
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ret = wait_for_completion_timeout(&mtx.done, TIMEOUT);
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}
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ww_mutex_unlock(&mtx.mutex);
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ww_acquire_fini(&ctx);
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if (ret) {
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pr_err("%s(flags=%x): mutual exclusion failure\n",
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__func__, flags);
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ret = -EINVAL;
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}
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flush_work(&mtx.work);
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destroy_work_on_stack(&mtx.work);
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return ret;
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#undef TIMEOUT
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}
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static int test_mutex(void)
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{
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int ret;
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int i;
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for (i = 0; i < __TEST_MTX_LAST; i++) {
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ret = __test_mutex(i);
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if (ret)
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return ret;
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}
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return 0;
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}
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static int test_aa(void)
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{
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struct ww_mutex mutex;
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struct ww_acquire_ctx ctx;
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int ret;
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ww_mutex_init(&mutex, &ww_class);
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ww_acquire_init(&ctx, &ww_class);
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ww_mutex_lock(&mutex, &ctx);
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if (ww_mutex_trylock(&mutex)) {
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pr_err("%s: trylocked itself!\n", __func__);
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ww_mutex_unlock(&mutex);
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ret = -EINVAL;
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goto out;
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}
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ret = ww_mutex_lock(&mutex, &ctx);
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if (ret != -EALREADY) {
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pr_err("%s: missed deadlock for recursing, ret=%d\n",
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__func__, ret);
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if (!ret)
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ww_mutex_unlock(&mutex);
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ret = -EINVAL;
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goto out;
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}
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ret = 0;
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out:
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ww_mutex_unlock(&mutex);
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ww_acquire_fini(&ctx);
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return ret;
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}
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struct test_abba {
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struct work_struct work;
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struct ww_mutex a_mutex;
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struct ww_mutex b_mutex;
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struct completion a_ready;
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struct completion b_ready;
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bool resolve;
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int result;
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};
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static void test_abba_work(struct work_struct *work)
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{
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struct test_abba *abba = container_of(work, typeof(*abba), work);
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struct ww_acquire_ctx ctx;
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int err;
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ww_acquire_init(&ctx, &ww_class);
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ww_mutex_lock(&abba->b_mutex, &ctx);
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complete(&abba->b_ready);
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wait_for_completion(&abba->a_ready);
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err = ww_mutex_lock(&abba->a_mutex, &ctx);
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if (abba->resolve && err == -EDEADLK) {
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ww_mutex_unlock(&abba->b_mutex);
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ww_mutex_lock_slow(&abba->a_mutex, &ctx);
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err = ww_mutex_lock(&abba->b_mutex, &ctx);
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}
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if (!err)
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ww_mutex_unlock(&abba->a_mutex);
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ww_mutex_unlock(&abba->b_mutex);
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ww_acquire_fini(&ctx);
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abba->result = err;
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}
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static int test_abba(bool resolve)
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{
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struct test_abba abba;
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struct ww_acquire_ctx ctx;
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int err, ret;
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ww_mutex_init(&abba.a_mutex, &ww_class);
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ww_mutex_init(&abba.b_mutex, &ww_class);
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INIT_WORK_ONSTACK(&abba.work, test_abba_work);
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init_completion(&abba.a_ready);
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init_completion(&abba.b_ready);
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abba.resolve = resolve;
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schedule_work(&abba.work);
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ww_acquire_init(&ctx, &ww_class);
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ww_mutex_lock(&abba.a_mutex, &ctx);
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complete(&abba.a_ready);
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wait_for_completion(&abba.b_ready);
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err = ww_mutex_lock(&abba.b_mutex, &ctx);
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if (resolve && err == -EDEADLK) {
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ww_mutex_unlock(&abba.a_mutex);
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ww_mutex_lock_slow(&abba.b_mutex, &ctx);
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err = ww_mutex_lock(&abba.a_mutex, &ctx);
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}
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if (!err)
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ww_mutex_unlock(&abba.b_mutex);
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ww_mutex_unlock(&abba.a_mutex);
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ww_acquire_fini(&ctx);
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flush_work(&abba.work);
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destroy_work_on_stack(&abba.work);
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ret = 0;
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if (resolve) {
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if (err || abba.result) {
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pr_err("%s: failed to resolve ABBA deadlock, A err=%d, B err=%d\n",
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__func__, err, abba.result);
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ret = -EINVAL;
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}
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} else {
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if (err != -EDEADLK && abba.result != -EDEADLK) {
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pr_err("%s: missed ABBA deadlock, A err=%d, B err=%d\n",
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__func__, err, abba.result);
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ret = -EINVAL;
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}
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}
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return ret;
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}
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struct test_cycle {
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struct work_struct work;
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struct ww_mutex a_mutex;
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struct ww_mutex *b_mutex;
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struct completion *a_signal;
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struct completion b_signal;
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int result;
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};
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static void test_cycle_work(struct work_struct *work)
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{
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struct test_cycle *cycle = container_of(work, typeof(*cycle), work);
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struct ww_acquire_ctx ctx;
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int err;
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ww_acquire_init(&ctx, &ww_class);
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ww_mutex_lock(&cycle->a_mutex, &ctx);
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complete(cycle->a_signal);
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wait_for_completion(&cycle->b_signal);
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err = ww_mutex_lock(cycle->b_mutex, &ctx);
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if (err == -EDEADLK) {
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ww_mutex_unlock(&cycle->a_mutex);
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ww_mutex_lock_slow(cycle->b_mutex, &ctx);
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err = ww_mutex_lock(&cycle->a_mutex, &ctx);
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}
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if (!err)
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ww_mutex_unlock(cycle->b_mutex);
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ww_mutex_unlock(&cycle->a_mutex);
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ww_acquire_fini(&ctx);
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cycle->result = err;
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}
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static int __test_cycle(unsigned int nthreads)
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{
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struct test_cycle *cycles;
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unsigned int n, last = nthreads - 1;
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int ret;
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cycles = kmalloc_array(nthreads, sizeof(*cycles), GFP_KERNEL);
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if (!cycles)
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return -ENOMEM;
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for (n = 0; n < nthreads; n++) {
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struct test_cycle *cycle = &cycles[n];
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ww_mutex_init(&cycle->a_mutex, &ww_class);
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if (n == last)
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cycle->b_mutex = &cycles[0].a_mutex;
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else
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cycle->b_mutex = &cycles[n + 1].a_mutex;
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if (n == 0)
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cycle->a_signal = &cycles[last].b_signal;
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else
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cycle->a_signal = &cycles[n - 1].b_signal;
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init_completion(&cycle->b_signal);
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INIT_WORK(&cycle->work, test_cycle_work);
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cycle->result = 0;
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}
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for (n = 0; n < nthreads; n++)
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queue_work(wq, &cycles[n].work);
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flush_workqueue(wq);
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ret = 0;
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for (n = 0; n < nthreads; n++) {
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struct test_cycle *cycle = &cycles[n];
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if (!cycle->result)
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continue;
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pr_err("cylic deadlock not resolved, ret[%d/%d] = %d\n",
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n, nthreads, cycle->result);
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ret = -EINVAL;
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break;
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}
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for (n = 0; n < nthreads; n++)
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ww_mutex_destroy(&cycles[n].a_mutex);
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kfree(cycles);
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return ret;
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}
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static int test_cycle(unsigned int ncpus)
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{
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unsigned int n;
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int ret;
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for (n = 2; n <= ncpus + 1; n++) {
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ret = __test_cycle(n);
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if (ret)
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return ret;
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}
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return 0;
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}
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struct stress {
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struct work_struct work;
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struct ww_mutex *locks;
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unsigned long timeout;
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int nlocks;
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};
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static int *get_random_order(int count)
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{
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int *order;
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int n, r, tmp;
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order = kmalloc_array(count, sizeof(*order), GFP_TEMPORARY);
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if (!order)
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return order;
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for (n = 0; n < count; n++)
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order[n] = n;
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for (n = count - 1; n > 1; n--) {
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r = get_random_int() % (n + 1);
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if (r != n) {
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tmp = order[n];
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order[n] = order[r];
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order[r] = tmp;
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}
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}
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return order;
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}
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static void dummy_load(struct stress *stress)
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{
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usleep_range(1000, 2000);
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}
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static void stress_inorder_work(struct work_struct *work)
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{
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struct stress *stress = container_of(work, typeof(*stress), work);
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const int nlocks = stress->nlocks;
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struct ww_mutex *locks = stress->locks;
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struct ww_acquire_ctx ctx;
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int *order;
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order = get_random_order(nlocks);
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if (!order)
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return;
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do {
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int contended = -1;
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int n, err;
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ww_acquire_init(&ctx, &ww_class);
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retry:
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err = 0;
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for (n = 0; n < nlocks; n++) {
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if (n == contended)
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continue;
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err = ww_mutex_lock(&locks[order[n]], &ctx);
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if (err < 0)
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break;
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}
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if (!err)
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dummy_load(stress);
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if (contended > n)
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ww_mutex_unlock(&locks[order[contended]]);
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contended = n;
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while (n--)
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ww_mutex_unlock(&locks[order[n]]);
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if (err == -EDEADLK) {
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ww_mutex_lock_slow(&locks[order[contended]], &ctx);
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goto retry;
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}
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if (err) {
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pr_err_once("stress (%s) failed with %d\n",
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__func__, err);
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break;
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}
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ww_acquire_fini(&ctx);
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} while (!time_after(jiffies, stress->timeout));
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kfree(order);
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kfree(stress);
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}
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struct reorder_lock {
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struct list_head link;
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struct ww_mutex *lock;
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};
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static void stress_reorder_work(struct work_struct *work)
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{
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struct stress *stress = container_of(work, typeof(*stress), work);
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LIST_HEAD(locks);
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struct ww_acquire_ctx ctx;
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struct reorder_lock *ll, *ln;
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int *order;
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int n, err;
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order = get_random_order(stress->nlocks);
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if (!order)
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return;
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for (n = 0; n < stress->nlocks; n++) {
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ll = kmalloc(sizeof(*ll), GFP_KERNEL);
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if (!ll)
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goto out;
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ll->lock = &stress->locks[order[n]];
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list_add(&ll->link, &locks);
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}
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kfree(order);
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order = NULL;
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do {
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ww_acquire_init(&ctx, &ww_class);
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list_for_each_entry(ll, &locks, link) {
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err = ww_mutex_lock(ll->lock, &ctx);
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if (!err)
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continue;
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ln = ll;
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list_for_each_entry_continue_reverse(ln, &locks, link)
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ww_mutex_unlock(ln->lock);
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if (err != -EDEADLK) {
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pr_err_once("stress (%s) failed with %d\n",
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__func__, err);
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break;
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}
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ww_mutex_lock_slow(ll->lock, &ctx);
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list_move(&ll->link, &locks); /* restarts iteration */
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}
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dummy_load(stress);
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list_for_each_entry(ll, &locks, link)
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ww_mutex_unlock(ll->lock);
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ww_acquire_fini(&ctx);
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} while (!time_after(jiffies, stress->timeout));
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out:
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list_for_each_entry_safe(ll, ln, &locks, link)
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kfree(ll);
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kfree(order);
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kfree(stress);
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}
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static void stress_one_work(struct work_struct *work)
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{
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struct stress *stress = container_of(work, typeof(*stress), work);
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const int nlocks = stress->nlocks;
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struct ww_mutex *lock = stress->locks + (get_random_int() % nlocks);
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int err;
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do {
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err = ww_mutex_lock(lock, NULL);
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if (!err) {
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dummy_load(stress);
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ww_mutex_unlock(lock);
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} else {
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pr_err_once("stress (%s) failed with %d\n",
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__func__, err);
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break;
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}
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} while (!time_after(jiffies, stress->timeout));
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kfree(stress);
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}
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#define STRESS_INORDER BIT(0)
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#define STRESS_REORDER BIT(1)
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#define STRESS_ONE BIT(2)
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#define STRESS_ALL (STRESS_INORDER | STRESS_REORDER | STRESS_ONE)
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static int stress(int nlocks, int nthreads, unsigned int flags)
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{
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struct ww_mutex *locks;
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int n;
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locks = kmalloc_array(nlocks, sizeof(*locks), GFP_KERNEL);
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if (!locks)
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return -ENOMEM;
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|
for (n = 0; n < nlocks; n++)
|
|
ww_mutex_init(&locks[n], &ww_class);
|
|
|
|
for (n = 0; nthreads; n++) {
|
|
struct stress *stress;
|
|
void (*fn)(struct work_struct *work);
|
|
|
|
fn = NULL;
|
|
switch (n & 3) {
|
|
case 0:
|
|
if (flags & STRESS_INORDER)
|
|
fn = stress_inorder_work;
|
|
break;
|
|
case 1:
|
|
if (flags & STRESS_REORDER)
|
|
fn = stress_reorder_work;
|
|
break;
|
|
case 2:
|
|
if (flags & STRESS_ONE)
|
|
fn = stress_one_work;
|
|
break;
|
|
}
|
|
|
|
if (!fn)
|
|
continue;
|
|
|
|
stress = kmalloc(sizeof(*stress), GFP_KERNEL);
|
|
if (!stress)
|
|
break;
|
|
|
|
INIT_WORK(&stress->work, fn);
|
|
stress->locks = locks;
|
|
stress->nlocks = nlocks;
|
|
stress->timeout = jiffies + 2*HZ;
|
|
|
|
queue_work(wq, &stress->work);
|
|
nthreads--;
|
|
}
|
|
|
|
flush_workqueue(wq);
|
|
|
|
for (n = 0; n < nlocks; n++)
|
|
ww_mutex_destroy(&locks[n]);
|
|
kfree(locks);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init test_ww_mutex_init(void)
|
|
{
|
|
int ncpus = num_online_cpus();
|
|
int ret;
|
|
|
|
wq = alloc_workqueue("test-ww_mutex", WQ_UNBOUND, 0);
|
|
if (!wq)
|
|
return -ENOMEM;
|
|
|
|
ret = test_mutex();
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = test_aa();
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = test_abba(false);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = test_abba(true);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = test_cycle(ncpus);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = stress(16, 2*ncpus, STRESS_INORDER);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = stress(16, 2*ncpus, STRESS_REORDER);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = stress(4095, hweight32(STRESS_ALL)*ncpus, STRESS_ALL);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __exit test_ww_mutex_exit(void)
|
|
{
|
|
destroy_workqueue(wq);
|
|
}
|
|
|
|
module_init(test_ww_mutex_init);
|
|
module_exit(test_ww_mutex_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Intel Corporation");
|