diff options
author | Peter Zijlstra <peterz@infradead.org> | 2025-04-16 18:29:05 +0200 |
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committer | Peter Zijlstra <peterz@infradead.org> | 2025-05-03 12:02:05 +0200 |
commit | 8486d12f558ff9e4e90331e8ef841d84bf3a8c24 (patch) | |
tree | 501e5568d77bae61ce2794d764932e3f45692012 /kernel/futex/core.c | |
parent | 2fb292096d950a67a1941949a08a60ddd3193da3 (diff) |
futex: Create hb scopes
Create explicit scopes for hb variables; almost pure re-indent.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250416162921.513656-6-bigeasy@linutronix.de
Diffstat (limited to 'kernel/futex/core.c')
-rw-r--r-- | kernel/futex/core.c | 83 |
1 files changed, 43 insertions, 40 deletions
diff --git a/kernel/futex/core.c b/kernel/futex/core.c index 7adc91487893..e4cb5ce9785b 100644 --- a/kernel/futex/core.c +++ b/kernel/futex/core.c @@ -944,7 +944,6 @@ static void exit_pi_state_list(struct task_struct *curr) { struct list_head *next, *head = &curr->pi_state_list; struct futex_pi_state *pi_state; - struct futex_hash_bucket *hb; union futex_key key = FUTEX_KEY_INIT; /* @@ -957,50 +956,54 @@ static void exit_pi_state_list(struct task_struct *curr) next = head->next; pi_state = list_entry(next, struct futex_pi_state, list); key = pi_state->key; - hb = futex_hash(&key); - - /* - * We can race against put_pi_state() removing itself from the - * list (a waiter going away). put_pi_state() will first - * decrement the reference count and then modify the list, so - * its possible to see the list entry but fail this reference - * acquire. - * - * In that case; drop the locks to let put_pi_state() make - * progress and retry the loop. - */ - if (!refcount_inc_not_zero(&pi_state->refcount)) { + if (1) { + struct futex_hash_bucket *hb; + + hb = futex_hash(&key); + + /* + * We can race against put_pi_state() removing itself from the + * list (a waiter going away). put_pi_state() will first + * decrement the reference count and then modify the list, so + * its possible to see the list entry but fail this reference + * acquire. + * + * In that case; drop the locks to let put_pi_state() make + * progress and retry the loop. + */ + if (!refcount_inc_not_zero(&pi_state->refcount)) { + raw_spin_unlock_irq(&curr->pi_lock); + cpu_relax(); + raw_spin_lock_irq(&curr->pi_lock); + continue; + } raw_spin_unlock_irq(&curr->pi_lock); - cpu_relax(); - raw_spin_lock_irq(&curr->pi_lock); - continue; - } - raw_spin_unlock_irq(&curr->pi_lock); - spin_lock(&hb->lock); - raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock); - raw_spin_lock(&curr->pi_lock); - /* - * We dropped the pi-lock, so re-check whether this - * task still owns the PI-state: - */ - if (head->next != next) { - /* retain curr->pi_lock for the loop invariant */ - raw_spin_unlock(&pi_state->pi_mutex.wait_lock); + spin_lock(&hb->lock); + raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock); + raw_spin_lock(&curr->pi_lock); + /* + * We dropped the pi-lock, so re-check whether this + * task still owns the PI-state: + */ + if (head->next != next) { + /* retain curr->pi_lock for the loop invariant */ + raw_spin_unlock(&pi_state->pi_mutex.wait_lock); + spin_unlock(&hb->lock); + put_pi_state(pi_state); + continue; + } + + WARN_ON(pi_state->owner != curr); + WARN_ON(list_empty(&pi_state->list)); + list_del_init(&pi_state->list); + pi_state->owner = NULL; + + raw_spin_unlock(&curr->pi_lock); + raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock); spin_unlock(&hb->lock); - put_pi_state(pi_state); - continue; } - WARN_ON(pi_state->owner != curr); - WARN_ON(list_empty(&pi_state->list)); - list_del_init(&pi_state->list); - pi_state->owner = NULL; - - raw_spin_unlock(&curr->pi_lock); - raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock); - spin_unlock(&hb->lock); - rt_mutex_futex_unlock(&pi_state->pi_mutex); put_pi_state(pi_state); |