Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Implement wraparound-safe refcount_t and kref_t types based on
     generic atomic primitives (Peter Zijlstra)

   - Improve and fix the ww_mutex code (Nicolai Hähnle)

   - Add self-tests to the ww_mutex code (Chris Wilson)

   - Optimize percpu-rwsems with the 'rcuwait' mechanism (Davidlohr
     Bueso)

   - Micro-optimize the current-task logic all around the core kernel
     (Davidlohr Bueso)

   - Tidy up after recent optimizations: remove stale code and APIs,
     clean up the code (Waiman Long)

   - ... plus misc fixes, updates and cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
  fork: Fix task_struct alignment
  locking/spinlock/debug: Remove spinlock lockup detection code
  lockdep: Fix incorrect condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS
  lkdtm: Convert to refcount_t testing
  kref: Implement 'struct kref' using refcount_t
  refcount_t: Introduce a special purpose refcount type
  sched/wake_q: Clarify queue reinit comment
  sched/wait, rcuwait: Fix typo in comment
  locking/mutex: Fix lockdep_assert_held() fail
  locking/rtmutex: Flip unlikely() branch to likely() in __rt_mutex_slowlock()
  locking/rwsem: Reinit wake_q after use
  locking/rwsem: Remove unnecessary atomic_long_t casts
  jump_labels: Move header guard #endif down where it belongs
  locking/atomic, kref: Implement kref_put_lock()
  locking/ww_mutex: Turn off __must_check for now
  locking/atomic, kref: Avoid more abuse
  locking/atomic, kref: Use kref_get_unless_zero() more
  locking/atomic, kref: Kill kref_sub()
  locking/atomic, kref: Add kref_read()
  locking/atomic, kref: Add KREF_INIT()
  ...

4 files changed, 16 insertions, 11 deletions

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 8147e8d56eb2..f39e3e11f9aa 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1358,7 +1358,7 @@ static int c_show(struct seq_file *m, void *p)
 	ifdebug(CACHE)
 		seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
 			   convert_to_wallclock(cp->expiry_time),
-			   atomic_read(&cp->ref.refcount), cp->flags);
+			   kref_read(&cp->ref), cp->flags);
 	cache_get(cp);
 	if (cache_check(cd, cp, NULL))
 		/* cache_check does a cache_put on failure */
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 9c9db55a0c1e..7bfe1fb42add 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -490,7 +490,7 @@ static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
 		svc_xprt_get(xprt);
 
 		dprintk("svc: transport %p dequeued, inuse=%d\n",
-			xprt, atomic_read(&xprt->xpt_ref.refcount));
+			xprt, kref_read(&xprt->xpt_ref));
 	}
 	spin_unlock_bh(&pool->sp_lock);
 out:
@@ -822,7 +822,7 @@ static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 		/* XPT_DATA|XPT_DEFERRED case: */
 		dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
 			rqstp, rqstp->rq_pool->sp_id, xprt,
-			atomic_read(&xprt->xpt_ref.refcount));
+			kref_read(&xprt->xpt_ref));
 		rqstp->rq_deferred = svc_deferred_dequeue(xprt);
 		if (rqstp->rq_deferred)
 			len = svc_deferred_recv(rqstp);
@@ -980,7 +980,7 @@ static void svc_age_temp_xprts(unsigned long closure)
 		 * through, close it. */
 		if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
 			continue;
-		if (atomic_read(&xprt->xpt_ref.refcount) > 1 ||
+		if (kref_read(&xprt->xpt_ref) > 1 ||
 		    test_bit(XPT_BUSY, &xprt->xpt_flags))
 			continue;
 		list_del_init(le);
diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c
index e112da8005b5..bb8db3cb8032 100644
--- a/net/sunrpc/svcauth.c
+++ b/net/sunrpc/svcauth.c
@@ -126,13 +126,18 @@ EXPORT_SYMBOL_GPL(svc_auth_unregister);
 static struct hlist_head	auth_domain_table[DN_HASHMAX];
 static DEFINE_SPINLOCK(auth_domain_lock);
 
+static void auth_domain_release(struct kref *kref)
+{
+	struct auth_domain *dom = container_of(kref, struct auth_domain, ref);
+
+	hlist_del(&dom->hash);
+	dom->flavour->domain_release(dom);
+	spin_unlock(&auth_domain_lock);
+}
+
 void auth_domain_put(struct auth_domain *dom)
 {
-	if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {
-		hlist_del(&dom->hash);
-		dom->flavour->domain_release(dom);
-		spin_unlock(&auth_domain_lock);
-	}
+	kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock);
 }
 EXPORT_SYMBOL_GPL(auth_domain_put);
 
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index ca2799af05a6..39652d390a9c 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -1201,9 +1201,9 @@ static void __svc_rdma_free(struct work_struct *work)
 		ib_drain_qp(rdma->sc_qp);
 
 	/* We should only be called from kref_put */
-	if (atomic_read(&xprt->xpt_ref.refcount) != 0)
+	if (kref_read(&xprt->xpt_ref) != 0)
 		pr_err("svcrdma: sc_xprt still in use? (%d)\n",
-		       atomic_read(&xprt->xpt_ref.refcount));
+		       kref_read(&xprt->xpt_ref));
 
 	/*
 	 * Destroy queued, but not processed read completions. Note