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()
  ...

10 files changed, 30 insertions, 25 deletions

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 1904a93f47d5..d491529332f4 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -920,7 +920,7 @@ static void chan_close_cb(struct l2cap_chan *chan)
                         BT_DBG("dev %p removing %speer %p", dev,
                                last ? "last " : "1 ", peer);
                         BT_DBG("chan %p orig refcnt %d", chan,
-                               atomic_read(&chan->kref.refcount));
+                               kref_read(&chan->kref));
 
                         l2cap_chan_put(chan);
                         break;
diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
index 5f123c3320a7..f0095fd79818 100644
--- a/net/bluetooth/a2mp.c
+++ b/net/bluetooth/a2mp.c
@@ -810,7 +810,7 @@ static struct l2cap_chan *a2mp_chan_open(struct l2cap_conn *conn, bool locked)
 /* AMP Manager functions */
 struct amp_mgr *amp_mgr_get(struct amp_mgr *mgr)
 {
-        BT_DBG("mgr %p orig refcnt %d", mgr, atomic_read(&mgr->kref.refcount));
+        BT_DBG("mgr %p orig refcnt %d", mgr, kref_read(&mgr->kref));
 
         kref_get(&mgr->kref);
 
@@ -833,7 +833,7 @@ static void amp_mgr_destroy(struct kref *kref)
 
 int amp_mgr_put(struct amp_mgr *mgr)
 {
-        BT_DBG("mgr %p orig refcnt %d", mgr, atomic_read(&mgr->kref.refcount));
+        BT_DBG("mgr %p orig refcnt %d", mgr, kref_read(&mgr->kref));
 
         return kref_put(&mgr->kref, &amp_mgr_destroy);
 }
diff --git a/net/bluetooth/amp.c b/net/bluetooth/amp.c
index e32f34189007..02a4ccc04e1e 100644
--- a/net/bluetooth/amp.c
+++ b/net/bluetooth/amp.c
@@ -24,7 +24,7 @@
 void amp_ctrl_get(struct amp_ctrl *ctrl)
 {
         BT_DBG("ctrl %p orig refcnt %d", ctrl,
-               atomic_read(&ctrl->kref.refcount));
+               kref_read(&ctrl->kref));
 
         kref_get(&ctrl->kref);
 }
@@ -42,7 +42,7 @@ static void amp_ctrl_destroy(struct kref *kref)
 int amp_ctrl_put(struct amp_ctrl *ctrl)
 {
         BT_DBG("ctrl %p orig refcnt %d", ctrl,
-               atomic_read(&ctrl->kref.refcount));
+               kref_read(&ctrl->kref));
 
         return kref_put(&ctrl->kref, &amp_ctrl_destroy);
 }
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ce0b5dd01953..fc7f321a3823 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -481,14 +481,14 @@ static void l2cap_chan_destroy(struct kref *kref)
 
 void l2cap_chan_hold(struct l2cap_chan *c)
 {
-        BT_DBG("chan %p orig refcnt %d", c, atomic_read(&c->kref.refcount));
+        BT_DBG("chan %p orig refcnt %d", c, kref_read(&c->kref));
 
         kref_get(&c->kref);
 }
 
 void l2cap_chan_put(struct l2cap_chan *c)
 {
-        BT_DBG("chan %p orig refcnt %d", c, atomic_read(&c->kref.refcount));
+        BT_DBG("chan %p orig refcnt %d", c, kref_read(&c->kref));
 
         kref_put(&c->kref, l2cap_chan_destroy);
 }
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 770c52701efa..bad3d4ae43f6 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3425,7 +3425,7 @@ static void ceph_msg_release(struct kref *kref)
 struct ceph_msg *ceph_msg_get(struct ceph_msg *msg)
 {
         dout("%s %p (was %d)\n", __func__, msg,
-             atomic_read(&msg->kref.refcount));
+             kref_read(&msg->kref));
         kref_get(&msg->kref);
         return msg;
 }
@@ -3434,7 +3434,7 @@ EXPORT_SYMBOL(ceph_msg_get);
 void ceph_msg_put(struct ceph_msg *msg)
 {
         dout("%s %p (was %d)\n", __func__, msg,
-             atomic_read(&msg->kref.refcount));
+             kref_read(&msg->kref));
         kref_put(&msg->kref, ceph_msg_release);
 }
 EXPORT_SYMBOL(ceph_msg_put);
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 842f049abb86..f3378ba1a828 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -438,7 +438,7 @@ static void ceph_osdc_release_request(struct kref *kref)
 void ceph_osdc_get_request(struct ceph_osd_request *req)
 {
         dout("%s %p (was %d)\n", __func__, req,
-             atomic_read(&req->r_kref.refcount));
+             kref_read(&req->r_kref));
         kref_get(&req->r_kref);
 }
 EXPORT_SYMBOL(ceph_osdc_get_request);
@@ -447,7 +447,7 @@ void ceph_osdc_put_request(struct ceph_osd_request *req)
 {
         if (req) {
                 dout("%s %p (was %d)\n", __func__, req,
-                     atomic_read(&req->r_kref.refcount));
+                     kref_read(&req->r_kref));
                 kref_put(&req->r_kref, ceph_osdc_release_request);
         }
 }
@@ -487,11 +487,11 @@ static void request_reinit(struct ceph_osd_request *req)
         struct ceph_msg *reply_msg = req->r_reply;
 
         dout("%s req %p\n", __func__, req);
-        WARN_ON(atomic_read(&req->r_kref.refcount) != 1);
+        WARN_ON(kref_read(&req->r_kref) != 1);
         request_release_checks(req);
 
-        WARN_ON(atomic_read(&request_msg->kref.refcount) != 1);
-        WARN_ON(atomic_read(&reply_msg->kref.refcount) != 1);
+        WARN_ON(kref_read(&request_msg->kref) != 1);
+        WARN_ON(kref_read(&reply_msg->kref) != 1);
         target_destroy(&req->r_t);
 
         request_init(req);
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