From 3822da3ed0676e01f83fe0518c333c8e9ba249bf Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Nicolai=20H=C3=A4hnle?= Date: Wed, 21 Dec 2016 19:46:31 +0100 Subject: [PATCH] locking/ww_mutex: Extract stamp comparison to __ww_mutex_stamp_after() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The function will be re-used in subsequent patches. Signed-off-by: Nicolai Hähnle Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Chris Wilson Cc: Andrew Morton Cc: Daniel Vetter Cc: Linus Torvalds Cc: Maarten Lankhorst Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-4-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar --- kernel/locking/mutex.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 24284497c425..9ad03b9a5f7f 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -281,6 +281,13 @@ static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww, ww_ctx->acquired++; } +static inline bool __sched +__ww_ctx_stamp_after(struct ww_acquire_ctx *a, struct ww_acquire_ctx *b) +{ + return a->stamp - b->stamp <= LONG_MAX && + (a->stamp != b->stamp || a > b); +} + /* * After acquiring lock with fastpath or when we lost out in contested * slowpath, set ctx and wake up any waiters so they can recheck. @@ -597,8 +604,7 @@ __ww_mutex_lock_check_stamp(struct mutex *lock, struct ww_acquire_ctx *ctx) if (!hold_ctx) return 0; - if (ctx->stamp - hold_ctx->stamp <= LONG_MAX && - (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) { + if (__ww_ctx_stamp_after(ctx, hold_ctx)) { #ifdef CONFIG_DEBUG_MUTEXES DEBUG_LOCKS_WARN_ON(ctx->contending_lock); ctx->contending_lock = ww;