summaryrefslogtreecommitdiffstats
path: root/debian/patches-rt/0148-rtmutex-add-ww_mutex-addon-for-mutex-rt.patch
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--debian/patches-rt/0148-rtmutex-add-ww_mutex-addon-for-mutex-rt.patch445
1 files changed, 445 insertions, 0 deletions
diff --git a/debian/patches-rt/0148-rtmutex-add-ww_mutex-addon-for-mutex-rt.patch b/debian/patches-rt/0148-rtmutex-add-ww_mutex-addon-for-mutex-rt.patch
new file mode 100644
index 000000000..86e8aed22
--- /dev/null
+++ b/debian/patches-rt/0148-rtmutex-add-ww_mutex-addon-for-mutex-rt.patch
@@ -0,0 +1,445 @@
+From d33397686c7cab5c3c263709534ec1e58ac42b54 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 12 Oct 2017 17:34:38 +0200
+Subject: [PATCH 148/347] rtmutex: add ww_mutex addon for mutex-rt
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/locking/rtmutex.c | 271 ++++++++++++++++++++++++++++++--
+ kernel/locking/rtmutex_common.h | 2 +
+ kernel/locking/rwsem-rt.c | 2 +-
+ 3 files changed, 261 insertions(+), 14 deletions(-)
+
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 5ff2189f1199..cc47d5aa93a1 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -23,6 +23,7 @@
+ #include <linux/sched/wake_q.h>
+ #include <linux/sched/debug.h>
+ #include <linux/timer.h>
++#include <linux/ww_mutex.h>
+
+ #include "rtmutex_common.h"
+
+@@ -1245,6 +1246,40 @@ EXPORT_SYMBOL(__rt_spin_lock_init);
+
+ #endif /* PREEMPT_RT_FULL */
+
++#ifdef CONFIG_PREEMPT_RT_FULL
++ static inline int __sched
++__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++ struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
++ struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
++
++ if (!hold_ctx)
++ return 0;
++
++ if (unlikely(ctx == hold_ctx))
++ return -EALREADY;
++
++ if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
++ (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
++#ifdef CONFIG_DEBUG_MUTEXES
++ DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
++ ctx->contending_lock = ww;
++#endif
++ return -EDEADLK;
++ }
++
++ return 0;
++}
++#else
++ static inline int __sched
++__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++ BUG();
++ return 0;
++}
++
++#endif
++
+ static inline int
+ try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+ struct rt_mutex_waiter *waiter)
+@@ -1523,7 +1558,8 @@ void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
+ static int __sched
+ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+- struct rt_mutex_waiter *waiter)
++ struct rt_mutex_waiter *waiter,
++ struct ww_acquire_ctx *ww_ctx)
+ {
+ int ret = 0;
+
+@@ -1541,6 +1577,12 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ break;
+ }
+
++ if (ww_ctx && ww_ctx->acquired > 0) {
++ ret = __mutex_lock_check_stamp(lock, ww_ctx);
++ if (ret)
++ break;
++ }
++
+ raw_spin_unlock_irq(&lock->wait_lock);
+
+ debug_rt_mutex_print_deadlock(waiter);
+@@ -1575,16 +1617,106 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
+ }
+ }
+
++static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
++ struct ww_acquire_ctx *ww_ctx)
++{
++#ifdef CONFIG_DEBUG_MUTEXES
++ /*
++ * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
++ * but released with a normal mutex_unlock in this call.
++ *
++ * This should never happen, always use ww_mutex_unlock.
++ */
++ DEBUG_LOCKS_WARN_ON(ww->ctx);
++
++ /*
++ * Not quite done after calling ww_acquire_done() ?
++ */
++ DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
++
++ if (ww_ctx->contending_lock) {
++ /*
++ * After -EDEADLK you tried to
++ * acquire a different ww_mutex? Bad!
++ */
++ DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
++
++ /*
++ * You called ww_mutex_lock after receiving -EDEADLK,
++ * but 'forgot' to unlock everything else first?
++ */
++ DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
++ ww_ctx->contending_lock = NULL;
++ }
++
++ /*
++ * Naughty, using a different class will lead to undefined behavior!
++ */
++ DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
++#endif
++ ww_ctx->acquired++;
++}
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++static void ww_mutex_account_lock(struct rt_mutex *lock,
++ struct ww_acquire_ctx *ww_ctx)
++{
++ struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
++ struct rt_mutex_waiter *waiter, *n;
++
++ /*
++ * This branch gets optimized out for the common case,
++ * and is only important for ww_mutex_lock.
++ */
++ ww_mutex_lock_acquired(ww, ww_ctx);
++ ww->ctx = ww_ctx;
++
++ /*
++ * Give any possible sleeping processes the chance to wake up,
++ * so they can recheck if they have to back off.
++ */
++ rbtree_postorder_for_each_entry_safe(waiter, n, &lock->waiters.rb_root,
++ tree_entry) {
++ /* XXX debug rt mutex waiter wakeup */
++
++ BUG_ON(waiter->lock != lock);
++ rt_mutex_wake_waiter(waiter);
++ }
++}
++
++#else
++
++static void ww_mutex_account_lock(struct rt_mutex *lock,
++ struct ww_acquire_ctx *ww_ctx)
++{
++ BUG();
++}
++#endif
++
+ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ enum rtmutex_chainwalk chwalk,
++ struct ww_acquire_ctx *ww_ctx,
+ struct rt_mutex_waiter *waiter)
+ {
+ int ret;
+
++#ifdef CONFIG_PREEMPT_RT_FULL
++ if (ww_ctx) {
++ struct ww_mutex *ww;
++
++ ww = container_of(lock, struct ww_mutex, base.lock);
++ if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
++ return -EALREADY;
++ }
++#endif
++
+ /* Try to acquire the lock again: */
+- if (try_to_take_rt_mutex(lock, current, NULL))
++ if (try_to_take_rt_mutex(lock, current, NULL)) {
++ if (ww_ctx)
++ ww_mutex_account_lock(lock, ww_ctx);
+ return 0;
++ }
+
+ set_current_state(state);
+
+@@ -1594,14 +1726,24 @@ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+
+ ret = task_blocks_on_rt_mutex(lock, waiter, current, chwalk);
+
+- if (likely(!ret))
++ if (likely(!ret)) {
+ /* sleep on the mutex */
+- ret = __rt_mutex_slowlock(lock, state, timeout, waiter);
++ ret = __rt_mutex_slowlock(lock, state, timeout, waiter,
++ ww_ctx);
++ } else if (ww_ctx) {
++ /* ww_mutex received EDEADLK, let it become EALREADY */
++ ret = __mutex_lock_check_stamp(lock, ww_ctx);
++ BUG_ON(!ret);
++ }
+
+ if (unlikely(ret)) {
+ __set_current_state(TASK_RUNNING);
+ remove_waiter(lock, waiter);
+- rt_mutex_handle_deadlock(ret, chwalk, waiter);
++ /* ww_mutex wants to report EDEADLK/EALREADY, let it */
++ if (!ww_ctx)
++ rt_mutex_handle_deadlock(ret, chwalk, waiter);
++ } else if (ww_ctx) {
++ ww_mutex_account_lock(lock, ww_ctx);
+ }
+
+ /*
+@@ -1618,7 +1760,8 @@ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ static int __sched
+ rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+- enum rtmutex_chainwalk chwalk)
++ enum rtmutex_chainwalk chwalk,
++ struct ww_acquire_ctx *ww_ctx)
+ {
+ struct rt_mutex_waiter waiter;
+ unsigned long flags;
+@@ -1636,7 +1779,8 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ */
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+- ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, &waiter);
++ ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, ww_ctx,
++ &waiter);
+
+ raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+@@ -1766,29 +1910,33 @@ static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
+ */
+ static inline int
+ rt_mutex_fastlock(struct rt_mutex *lock, int state,
++ struct ww_acquire_ctx *ww_ctx,
+ int (*slowfn)(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+- enum rtmutex_chainwalk chwalk))
++ enum rtmutex_chainwalk chwalk,
++ struct ww_acquire_ctx *ww_ctx))
+ {
+ if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+ return 0;
+
+- return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
++ return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK, ww_ctx);
+ }
+
+ static inline int
+ rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ enum rtmutex_chainwalk chwalk,
++ struct ww_acquire_ctx *ww_ctx,
+ int (*slowfn)(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+- enum rtmutex_chainwalk chwalk))
++ enum rtmutex_chainwalk chwalk,
++ struct ww_acquire_ctx *ww_ctx))
+ {
+ if (chwalk == RT_MUTEX_MIN_CHAINWALK &&
+ likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+ return 0;
+
+- return slowfn(lock, state, timeout, chwalk);
++ return slowfn(lock, state, timeout, chwalk, ww_ctx);
+ }
+
+ static inline int
+@@ -1833,7 +1981,7 @@ rt_mutex_fastunlock(struct rt_mutex *lock,
+ int __sched __rt_mutex_lock_state(struct rt_mutex *lock, int state)
+ {
+ might_sleep();
+- return rt_mutex_fastlock(lock, state, rt_mutex_slowlock);
++ return rt_mutex_fastlock(lock, state, NULL, rt_mutex_slowlock);
+ }
+
+ /**
+@@ -1953,6 +2101,7 @@ rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout)
+ mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ ret = rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
+ RT_MUTEX_MIN_CHAINWALK,
++ NULL,
+ rt_mutex_slowlock);
+ if (ret)
+ mutex_release(&lock->dep_map, 1, _RET_IP_);
+@@ -2299,7 +2448,7 @@ int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
+ raw_spin_lock_irq(&lock->wait_lock);
+ /* sleep on the mutex */
+ set_current_state(TASK_INTERRUPTIBLE);
+- ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
++ ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, NULL);
+ /*
+ * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
+ * have to fix that up.
+@@ -2384,3 +2533,99 @@ bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
+
+ return cleanup;
+ }
++
++static inline int
++ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
++ unsigned tmp;
++
++ if (ctx->deadlock_inject_countdown-- == 0) {
++ tmp = ctx->deadlock_inject_interval;
++ if (tmp > UINT_MAX/4)
++ tmp = UINT_MAX;
++ else
++ tmp = tmp*2 + tmp + tmp/2;
++
++ ctx->deadlock_inject_interval = tmp;
++ ctx->deadlock_inject_countdown = tmp;
++ ctx->contending_lock = lock;
++
++ ww_mutex_unlock(lock);
++
++ return -EDEADLK;
++ }
++#endif
++
++ return 0;
++}
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++int __sched
++ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++ int ret;
++
++ might_sleep();
++
++ mutex_acquire_nest(&lock->base.dep_map, 0, 0,
++ ctx ? &ctx->dep_map : NULL, _RET_IP_);
++ ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL, 0,
++ ctx);
++ if (ret)
++ mutex_release(&lock->base.dep_map, 1, _RET_IP_);
++ else if (!ret && ctx && ctx->acquired > 1)
++ return ww_mutex_deadlock_injection(lock, ctx);
++
++ return ret;
++}
++EXPORT_SYMBOL_GPL(ww_mutex_lock_interruptible);
++
++int __sched
++ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++ int ret;
++
++ might_sleep();
++
++ mutex_acquire_nest(&lock->base.dep_map, 0, 0,
++ ctx ? &ctx->dep_map : NULL, _RET_IP_);
++ ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL, 0,
++ ctx);
++ if (ret)
++ mutex_release(&lock->base.dep_map, 1, _RET_IP_);
++ else if (!ret && ctx && ctx->acquired > 1)
++ return ww_mutex_deadlock_injection(lock, ctx);
++
++ return ret;
++}
++EXPORT_SYMBOL_GPL(ww_mutex_lock);
++
++void __sched ww_mutex_unlock(struct ww_mutex *lock)
++{
++ int nest = !!lock->ctx;
++
++ /*
++ * The unlocking fastpath is the 0->1 transition from 'locked'
++ * into 'unlocked' state:
++ */
++ if (nest) {
++#ifdef CONFIG_DEBUG_MUTEXES
++ DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
++#endif
++ if (lock->ctx->acquired > 0)
++ lock->ctx->acquired--;
++ lock->ctx = NULL;
++ }
++
++ mutex_release(&lock->base.dep_map, nest, _RET_IP_);
++ __rt_mutex_unlock(&lock->base.lock);
++}
++EXPORT_SYMBOL(ww_mutex_unlock);
++
++int __rt_mutex_owner_current(struct rt_mutex *lock)
++{
++ return rt_mutex_owner(lock) == current;
++}
++EXPORT_SYMBOL(__rt_mutex_owner_current);
++#endif
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index 7c1dd1bd95c7..8e0c592273e6 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -164,6 +164,7 @@ extern void rt_mutex_postunlock(struct wake_q_head *wake_q,
+ struct wake_q_head *wake_sleeper_q);
+
+ /* RW semaphore special interface */
++struct ww_acquire_ctx;
+
+ extern int __rt_mutex_lock_state(struct rt_mutex *lock, int state);
+ extern int __rt_mutex_trylock(struct rt_mutex *lock);
+@@ -171,6 +172,7 @@ extern void __rt_mutex_unlock(struct rt_mutex *lock);
+ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ enum rtmutex_chainwalk chwalk,
++ struct ww_acquire_ctx *ww_ctx,
+ struct rt_mutex_waiter *waiter);
+ void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+ struct rt_mutex_waiter *waiter,
+diff --git a/kernel/locking/rwsem-rt.c b/kernel/locking/rwsem-rt.c
+index 7d3c5cf3d23d..660e22caf709 100644
+--- a/kernel/locking/rwsem-rt.c
++++ b/kernel/locking/rwsem-rt.c
+@@ -131,7 +131,7 @@ static int __sched __down_read_common(struct rw_semaphore *sem, int state)
+ */
+ rt_mutex_init_waiter(&waiter, false);
+ ret = rt_mutex_slowlock_locked(m, state, NULL, RT_MUTEX_MIN_CHAINWALK,
+- &waiter);
++ NULL, &waiter);
+ /*
+ * The slowlock() above is guaranteed to return with the rtmutex (for
+ * ret = 0) is now held, so there can't be a writer active. Increment
+--
+2.36.1
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 17:49:24 +0000