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Subject[PATCH 5/8] locking/mutex: Introduce ww_mutex_set_context_slowpath
Date
... which is equivalent to the fastpath counter part.
This mainly allows getting some ww specific code out
of generic mutex paths.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
kernel/locking/mutex.c | 43 ++++++++++++++++++++++++++-----------------
1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index caa3c9f..5b6df69 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -155,7 +155,7 @@ static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
*/
static __always_inline void
ww_mutex_set_context_fastpath(struct ww_mutex *lock,
- struct ww_acquire_ctx *ctx)
+ struct ww_acquire_ctx *ctx)
{
unsigned long flags;
struct mutex_waiter *cur;
@@ -191,6 +191,30 @@ ww_mutex_set_context_fastpath(struct ww_mutex *lock,
spin_unlock_mutex(&lock->base.wait_lock, flags);
}

+/*
+ * after acquiring lock in the slowpath or when we lost out in contested
+ * slowpath, set ctx and wake up any waiters so they can recheck.
+ *
+ * Callers must hold the mutex wait_lock.
+ */
+static __always_inline void
+ww_mutex_set_context_slowpath(struct ww_mutex *lock,
+ struct ww_acquire_ctx *ctx)
+{
+ struct mutex_waiter *cur;
+
+ ww_mutex_lock_acquired(lock, ctx);
+ lock->ctx = ctx;
+
+ /*
+ * Give any possible sleeping processes the chance to wake up,
+ * so they can recheck if they have to back off.
+ */
+ list_for_each_entry(cur, &lock->base.wait_list, list) {
+ debug_mutex_wake_waiter(lock->base, cur);
+ wake_up_process(cur->task);
+ }
+}

#ifdef CONFIG_MUTEX_SPIN_ON_OWNER
/*
@@ -576,23 +600,8 @@ skip_wait:

if (ww_ctx) {
struct ww_mutex *ww = container_of(lock, struct ww_mutex, base);
- struct mutex_waiter *cur;

- /*
- * This branch gets optimized out for the common case,
- * and is only important for ww_mutex_lock.
- */
- ww_mutex_lock_acquired(ww, ww_ctx);
- ww->ctx = ww_ctx;
-
- /*
- * Give any possible sleeping processes the chance to wake up,
- * so they can recheck if they have to back off.
- */
- list_for_each_entry(cur, &lock->wait_list, list) {
- debug_mutex_wake_waiter(lock, cur);
- wake_up_process(cur->task);
- }
+ ww_mutex_set_context_slowpath(ww, ww_ctx);
}

spin_unlock_mutex(&lock->wait_lock, flags);
--
2.1.2


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