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authorNicolai Hähnle <Nicolai.Haehnle@amd.com>2016-12-21 19:46:31 +0100
committerIngo Molnar <mingo@kernel.org>2017-01-14 11:14:39 +0100
commit3822da3ed0676e01f83fe0518c333c8e9ba249bf (patch)
treeb1fef389fa35df9745b0aa9ec8f76a0788622934 /kernel/locking
parente274795ea7b7caa0fd74ef651594382a69e2a951 (diff)
locking/ww_mutex: Extract stamp comparison to __ww_mutex_stamp_after()
The function will be re-used in subsequent patches. Signed-off-by: Nicolai Hähnle <Nicolai.Haehnle@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> 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 <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/mutex.c10
1 files 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;