Commit 23d599eb authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

locking/ww_mutex: Abstract out the waiter iteration 



Split out the waiter iteration functions so they can be substituted for a
rtmutex based ww_mutex later.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.509186185@linutronix.de
parent 5297ccb2

kernel/locking/ww_mutex.h

+53 −4
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */



static inline struct mutex_waiter *

__ww_waiter_first(struct mutex *lock)

{

	struct mutex_waiter *w;



	w = list_first_entry(&lock->wait_list, struct mutex_waiter, list);

	if (list_entry_is_head(w, &lock->wait_list, list))

		return NULL;



	return w;

}



static inline struct mutex_waiter *

__ww_waiter_next(struct mutex *lock, struct mutex_waiter *w)

{

	w = list_next_entry(w, list);

	if (list_entry_is_head(w, &lock->wait_list, list))

		return NULL;



	return w;

}



static inline struct mutex_waiter *

__ww_waiter_prev(struct mutex *lock, struct mutex_waiter *w)

{

	w = list_prev_entry(w, list);

	if (list_entry_is_head(w, &lock->wait_list, list))

		return NULL;



	return w;

}



static inline struct mutex_waiter *

__ww_waiter_last(struct mutex *lock)

{

	struct mutex_waiter *w;



	w = list_last_entry(&lock->wait_list, struct mutex_waiter, list);

	if (list_entry_is_head(w, &lock->wait_list, list))

		return NULL;



	return w;

}



/*

 * Wait-Die:

 *   The newer transactions are killed when:
@@ -161,7 +205,9 @@ __ww_mutex_check_waiters(struct mutex *lock, struct ww_acquire_ctx *ww_ctx) 


	lockdep_assert_held(&lock->wait_lock);



	list_for_each_entry(cur, &lock->wait_list, list) {

	for (cur = __ww_waiter_first(lock); cur;

	     cur = __ww_waiter_next(lock, cur)) {



		if (!cur->ww_ctx)

			continue;
@@ -263,8 +309,9 @@ __ww_mutex_check_kill(struct mutex *lock, struct mutex_waiter *waiter, 
	 * If there is a waiter in front of us that has a context, then its

	 * stamp is earlier than ours and we must kill ourself.

	 */

	cur = waiter;

	list_for_each_entry_continue_reverse(cur, &lock->wait_list, list) {

	for (cur = __ww_waiter_prev(lock, waiter); cur;

	     cur = __ww_waiter_prev(lock, cur)) {



		if (!cur->ww_ctx)

			continue;
@@ -309,7 +356,9 @@ __ww_mutex_add_waiter(struct mutex_waiter *waiter, 
	 * may wound the lock holder.

	 */

	pos = &lock->wait_list;

	list_for_each_entry_reverse(cur, &lock->wait_list, list) {

	for (cur = __ww_waiter_last(lock); cur;

	     cur = __ww_waiter_prev(lock, cur)) {



		if (!cur->ww_ctx)

			continue;