From 2c935bc57221cc2edc787c72ea0e2d30cdcd3d5e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 14 Nov 2016 17:29:48 +0100 Subject: locking/atomic, kref: Add kref_read() Since we need to change the implementation, stop exposing internals. Provide kref_read() to read the current reference count; typically used for debug messages. Kills two anti-patterns: atomic_read(&kref->refcount) kref->refcount.counter Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- net/bluetooth/6lowpan.c | 2 +- net/bluetooth/a2mp.c | 4 ++-- net/bluetooth/amp.c | 4 ++-- net/bluetooth/l2cap_core.c | 4 ++-- net/ceph/messenger.c | 4 ++-- net/ceph/osd_client.c | 10 +++++----- net/sunrpc/cache.c | 2 +- net/sunrpc/svc_xprt.c | 6 +++--- net/sunrpc/xprtrdma/svc_rdma_transport.c | 4 ++-- 9 files changed, 20 insertions(+), 20 deletions(-) (limited to 'net') 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, &_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, &_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 3bc1d61694cb..04e7f8707d71 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: @@ -820,7 +820,7 @@ 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); @@ -978,7 +978,7 @@ 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/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 -- cgit v1.2.3-70-g09d2 From 0a13cd1a05e7a549259d4f803d2ec2efda07ed7c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 14 Nov 2016 18:03:11 +0100 Subject: locking/atomic, kref: Implement kref_put_lock() Because home-rolling your own is _awesome_, stop doing it. Provide kref_put_lock(), just like kref_put_mutex() but for a spinlock. Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Greg Kroah-Hartman Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/kref.h | 22 ++++++++++++++++------ net/sunrpc/svcauth.c | 15 ++++++++++----- 2 files changed, 26 insertions(+), 11 deletions(-) (limited to 'net') diff --git a/include/linux/kref.h b/include/linux/kref.h index 31c49a64cdf9..9db9685fed84 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -19,6 +19,7 @@ #include #include #include +#include struct kref { atomic_t refcount; @@ -86,12 +87,21 @@ static inline int kref_put_mutex(struct kref *kref, struct mutex *lock) { WARN_ON(release == NULL); - if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) { - mutex_lock(lock); - if (unlikely(!atomic_dec_and_test(&kref->refcount))) { - mutex_unlock(lock); - return 0; - } + + if (atomic_dec_and_mutex_lock(&kref->refcount, lock)) { + release(kref); + return 1; + } + return 0; +} + +static inline int kref_put_lock(struct kref *kref, + void (*release)(struct kref *kref), + spinlock_t *lock) +{ + WARN_ON(release == NULL); + + if (atomic_dec_and_lock(&kref->refcount, lock)) { release(kref); return 1; } 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); -- cgit v1.2.3-70-g09d2