3.12.38-rt53-rc1 stable review patch. If anyone has any objections, please let me know.
------------------ From: Mike Galbraith <[email protected]> If the caller already holds the mutex, task_blocks_on_rt_mutex() returns -EDEADLK, we proceed directly to rt_mutex_handle_deadlock() where it's instant game over. Let ww_mutexes return EDEADLK/EALREADY as they want to instead. Cc: [email protected] Signed-off-by: Mike Galbraith <[email protected]> Signed-off-by: Sebastian Andrzej Siewior <[email protected]> Signed-off-by: Steven Rostedt <[email protected]> --- kernel/rtmutex.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index e8a6555a670a..7601c1332a88 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -1621,13 +1621,20 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, if (likely(!ret)) 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); + } set_current_state(TASK_RUNNING); if (unlikely(ret)) { if (rt_mutex_has_waiters(lock)) remove_waiter(lock, &waiter); - rt_mutex_handle_deadlock(ret, chwalk, &waiter); + /* ww_mutex want to report EDEADLK/EALREADY, let them */ + if (!ww_ctx) + rt_mutex_handle_deadlock(ret, chwalk, &waiter); } else if (ww_ctx) { ww_mutex_account_lock(lock, ww_ctx); } @@ -2166,8 +2173,7 @@ __ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ww_c might_sleep(); mutex_acquire_nest(&lock->base.dep_map, 0, 0, &ww_ctx->dep_map, _RET_IP_); - ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL, - RT_MUTEX_FULL_CHAINWALK, ww_ctx); + ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL, 0, ww_ctx); if (ret) mutex_release(&lock->base.dep_map, 1, _RET_IP_); else if (!ret && ww_ctx->acquired > 1) @@ -2185,8 +2191,7 @@ __ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ww_ctx) might_sleep(); mutex_acquire_nest(&lock->base.dep_map, 0, 0, &ww_ctx->dep_map, _RET_IP_); - ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL, - RT_MUTEX_FULL_CHAINWALK, ww_ctx); + ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL, 0, ww_ctx); if (ret) mutex_release(&lock->base.dep_map, 1, _RET_IP_); else if (!ret && ww_ctx->acquired > 1) @@ -2198,11 +2203,13 @@ 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 (lock->ctx) { + if (nest) { #ifdef CONFIG_DEBUG_MUTEXES DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired); #endif @@ -2211,7 +2218,7 @@ void __sched ww_mutex_unlock(struct ww_mutex *lock) lock->ctx = NULL; } - mutex_release(&lock->base.dep_map, 1, _RET_IP_); + mutex_release(&lock->base.dep_map, nest, _RET_IP_); rt_mutex_unlock(&lock->base.lock); } EXPORT_SYMBOL(ww_mutex_unlock); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
