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locking/ww_mutex: Simplify use_ww_ctx & ww_ctx handling
[ Upstream commit 5de2055d31
]
The use_ww_ctx flag is passed to mutex_optimistic_spin(), but the
function doesn't use it. The frequent use of the (use_ww_ctx && ww_ctx)
combination is repetitive.
In fact, ww_ctx should not be used at all if !use_ww_ctx. Simplify
ww_mutex code by dropping use_ww_ctx from mutex_optimistic_spin() an
clear ww_ctx if !use_ww_ctx. In this way, we can replace (use_ww_ctx &&
ww_ctx) by just (ww_ctx).
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210316153119.13802-2-longman@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
1e2a75c24a
commit
905ef030bd
1 changed files with 14 additions and 11 deletions
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@ -636,7 +636,7 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
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*/
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static __always_inline bool
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mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
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const bool use_ww_ctx, struct mutex_waiter *waiter)
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struct mutex_waiter *waiter)
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{
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if (!waiter) {
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/*
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@ -712,7 +712,7 @@ mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
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#else
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static __always_inline bool
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mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
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const bool use_ww_ctx, struct mutex_waiter *waiter)
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struct mutex_waiter *waiter)
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{
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return false;
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}
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@ -932,6 +932,9 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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struct ww_mutex *ww;
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int ret;
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if (!use_ww_ctx)
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ww_ctx = NULL;
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might_sleep();
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#ifdef CONFIG_DEBUG_MUTEXES
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@ -939,7 +942,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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#endif
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ww = container_of(lock, struct ww_mutex, base);
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if (use_ww_ctx && ww_ctx) {
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if (ww_ctx) {
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if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
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return -EALREADY;
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@ -956,10 +959,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
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if (__mutex_trylock(lock) ||
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mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, NULL)) {
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mutex_optimistic_spin(lock, ww_ctx, NULL)) {
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/* got the lock, yay! */
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lock_acquired(&lock->dep_map, ip);
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if (use_ww_ctx && ww_ctx)
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if (ww_ctx)
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ww_mutex_set_context_fastpath(ww, ww_ctx);
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preempt_enable();
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return 0;
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@ -970,7 +973,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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* After waiting to acquire the wait_lock, try again.
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*/
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if (__mutex_trylock(lock)) {
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if (use_ww_ctx && ww_ctx)
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if (ww_ctx)
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__ww_mutex_check_waiters(lock, ww_ctx);
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goto skip_wait;
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@ -1023,7 +1026,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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goto err;
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}
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if (use_ww_ctx && ww_ctx) {
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if (ww_ctx) {
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ret = __ww_mutex_check_kill(lock, &waiter, ww_ctx);
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if (ret)
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goto err;
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@ -1036,7 +1039,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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* ww_mutex needs to always recheck its position since its waiter
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* list is not FIFO ordered.
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*/
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if ((use_ww_ctx && ww_ctx) || !first) {
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if (ww_ctx || !first) {
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first = __mutex_waiter_is_first(lock, &waiter);
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if (first)
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__mutex_set_flag(lock, MUTEX_FLAG_HANDOFF);
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@ -1049,7 +1052,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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* or we must see its unlock and acquire.
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*/
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if (__mutex_trylock(lock) ||
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(first && mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, &waiter)))
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(first && mutex_optimistic_spin(lock, ww_ctx, &waiter)))
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break;
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spin_lock(&lock->wait_lock);
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@ -1058,7 +1061,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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acquired:
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__set_current_state(TASK_RUNNING);
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if (use_ww_ctx && ww_ctx) {
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if (ww_ctx) {
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/*
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* Wound-Wait; we stole the lock (!first_waiter), check the
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* waiters as anyone might want to wound us.
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@ -1078,7 +1081,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
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/* got the lock - cleanup and rejoice! */
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lock_acquired(&lock->dep_map, ip);
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if (use_ww_ctx && ww_ctx)
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if (ww_ctx)
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ww_mutex_lock_acquired(ww, ww_ctx);
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spin_unlock(&lock->wait_lock);
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