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locking/ww_mutex: Abstract out waiter enqueueing

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The upcoming rtmutex based ww_mutex needs a different handling for
enqueueing a waiter. Split it out into a helper function.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211304.566318143@linutronix.de
This commit is contained in:
Peter Zijlstra 2021-08-15 23:28:47 +02:00 committed by Ingo Molnar
parent 23d599eb23
commit 843dac28f9
1 changed files with 13 additions and 6 deletions
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19
kernel/locking/ww_mutex.h
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@ -44,6 +44,15 @@ __ww_waiter_last(struct mutex *lock)
return w;
}
static inline void
__ww_waiter_add(struct mutex *lock, struct mutex_waiter *waiter, struct mutex_waiter *pos)
{
struct list_head *p = &lock->wait_list;
if (pos)
p = &pos->list;
__mutex_add_waiter(lock, waiter, p);
}
/*
* Wait-Die:
* The newer transactions are killed when:
@ -337,12 +346,11 @@ __ww_mutex_add_waiter(struct mutex_waiter *waiter,
struct mutex *lock,
struct ww_acquire_ctx *ww_ctx)
{
struct mutex_waiter *cur;
struct list_head *pos;
struct mutex_waiter *cur, *pos = NULL;
bool is_wait_die;
if (!ww_ctx) {
__mutex_add_waiter(lock, waiter, &lock->wait_list);
__ww_waiter_add(lock, waiter, NULL);
return 0;
}
@ -355,7 +363,6 @@ __ww_mutex_add_waiter(struct mutex_waiter *waiter,
* never die here, but they are sorted in stamp order and
* may wound the lock holder.
*/
pos = &lock->wait_list;
for (cur = __ww_waiter_last(lock); cur;
cur = __ww_waiter_prev(lock, cur)) {
@ -378,13 +385,13 @@ __ww_mutex_add_waiter(struct mutex_waiter *waiter,
break;
}
pos = &cur->list;
pos = cur;
/* Wait-Die: ensure younger waiters die. */
__ww_mutex_die(lock, cur, ww_ctx);
}
__mutex_add_waiter(lock, waiter, pos);
__ww_waiter_add(lock, waiter, pos);
/*
* Wound-Wait: if we're blocking on a mutex owned by a younger context,