From de910bd92137005b5e1ecaf2ce68053d7d7d5350 Mon Sep 17 00:00:00 2001 From: Or Gerlitz Date: Mon, 14 Jul 2008 23:48:53 -0700 Subject: RDMA/cma: Simplify locking needed for serialization of callbacks The RDMA CM has some logic in place to make sure that callbacks on a given CM ID are delivered to the consumer in a serialized manner. Specifically it has code to protect against a device removal racing with a running callback function. This patch simplifies this logic by using a mutex per ID instead of a wait queue and atomic variable. This means that cma_disable_remove() now is more properly named to cma_disable_callback(), and cma_enable_remove() can now be removed because it just would become a trivial wrapper around mutex_unlock(). Signed-off-by: Or Gerlitz Signed-off-by: Roland Dreier --- drivers/infiniband/core/cma.c | 106 ++++++++++++++++++++---------------------- 1 file changed, 50 insertions(+), 56 deletions(-) (limited to 'drivers/infiniband') diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index 5fb506a41776..ae11d5cc74d0 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -130,8 +130,7 @@ struct rdma_id_private { struct completion comp; atomic_t refcount; - wait_queue_head_t wait_remove; - atomic_t dev_remove; + struct mutex handler_mutex; int backlog; int timeout_ms; @@ -355,26 +354,15 @@ static void cma_deref_id(struct rdma_id_private *id_priv) complete(&id_priv->comp); } -static int cma_disable_remove(struct rdma_id_private *id_priv, +static int cma_disable_callback(struct rdma_id_private *id_priv, enum cma_state state) { - unsigned long flags; - int ret; - - spin_lock_irqsave(&id_priv->lock, flags); - if (id_priv->state == state) { - atomic_inc(&id_priv->dev_remove); - ret = 0; - } else - ret = -EINVAL; - spin_unlock_irqrestore(&id_priv->lock, flags); - return ret; -} - -static void cma_enable_remove(struct rdma_id_private *id_priv) -{ - if (atomic_dec_and_test(&id_priv->dev_remove)) - wake_up(&id_priv->wait_remove); + mutex_lock(&id_priv->handler_mutex); + if (id_priv->state != state) { + mutex_unlock(&id_priv->handler_mutex); + return -EINVAL; + } + return 0; } static int cma_has_cm_dev(struct rdma_id_private *id_priv) @@ -399,8 +387,7 @@ struct rdma_cm_id *rdma_create_id(rdma_cm_event_handler event_handler, mutex_init(&id_priv->qp_mutex); init_completion(&id_priv->comp); atomic_set(&id_priv->refcount, 1); - init_waitqueue_head(&id_priv->wait_remove); - atomic_set(&id_priv->dev_remove, 0); + mutex_init(&id_priv->handler_mutex); INIT_LIST_HEAD(&id_priv->listen_list); INIT_LIST_HEAD(&id_priv->mc_list); get_random_bytes(&id_priv->seq_num, sizeof id_priv->seq_num); @@ -927,7 +914,7 @@ static int cma_ib_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event) struct rdma_cm_event event; int ret = 0; - if (cma_disable_remove(id_priv, CMA_CONNECT)) + if (cma_disable_callback(id_priv, CMA_CONNECT)) return 0; memset(&event, 0, sizeof event); @@ -984,12 +971,12 @@ static int cma_ib_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event) /* Destroy the CM ID by returning a non-zero value. */ id_priv->cm_id.ib = NULL; cma_exch(id_priv, CMA_DESTROYING); - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); rdma_destroy_id(&id_priv->id); return ret; } out: - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); return ret; } @@ -1101,7 +1088,7 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event) int offset, ret; listen_id = cm_id->context; - if (cma_disable_remove(listen_id, CMA_LISTEN)) + if (cma_disable_callback(listen_id, CMA_LISTEN)) return -ECONNABORTED; memset(&event, 0, sizeof event); @@ -1122,7 +1109,7 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event) goto out; } - atomic_inc(&conn_id->dev_remove); + mutex_lock_nested(&conn_id->handler_mutex, SINGLE_DEPTH_NESTING); mutex_lock(&lock); ret = cma_acquire_dev(conn_id); mutex_unlock(&lock); @@ -1144,7 +1131,7 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event) !cma_is_ud_ps(conn_id->id.ps)) ib_send_cm_mra(cm_id, CMA_CM_MRA_SETTING, NULL, 0); mutex_unlock(&lock); - cma_enable_remove(conn_id); + mutex_unlock(&conn_id->handler_mutex); goto out; } @@ -1153,11 +1140,11 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event) release_conn_id: cma_exch(conn_id, CMA_DESTROYING); - cma_enable_remove(conn_id); + mutex_unlock(&conn_id->handler_mutex); rdma_destroy_id(&conn_id->id); out: - cma_enable_remove(listen_id); + mutex_unlock(&listen_id->handler_mutex); return ret; } @@ -1223,7 +1210,7 @@ static int cma_iw_handler(struct iw_cm_id *iw_id, struct iw_cm_event *iw_event) struct sockaddr_in *sin; int ret = 0; - if (cma_disable_remove(id_priv, CMA_CONNECT)) + if (cma_disable_callback(id_priv, CMA_CONNECT)) return 0; memset(&event, 0, sizeof event); @@ -1267,12 +1254,12 @@ static int cma_iw_handler(struct iw_cm_id *iw_id, struct iw_cm_event *iw_event) /* Destroy the CM ID by returning a non-zero value. */ id_priv->cm_id.iw = NULL; cma_exch(id_priv, CMA_DESTROYING); - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); rdma_destroy_id(&id_priv->id); return ret; } - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); return ret; } @@ -1288,7 +1275,7 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id, struct ib_device_attr attr; listen_id = cm_id->context; - if (cma_disable_remove(listen_id, CMA_LISTEN)) + if (cma_disable_callback(listen_id, CMA_LISTEN)) return -ECONNABORTED; /* Create a new RDMA id for the new IW CM ID */ @@ -1300,19 +1287,19 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id, goto out; } conn_id = container_of(new_cm_id, struct rdma_id_private, id); - atomic_inc(&conn_id->dev_remove); + mutex_lock_nested(&conn_id->handler_mutex, SINGLE_DEPTH_NESTING); conn_id->state = CMA_CONNECT; dev = ip_dev_find(&init_net, iw_event->local_addr.sin_addr.s_addr); if (!dev) { ret = -EADDRNOTAVAIL; - cma_enable_remove(conn_id); + mutex_unlock(&conn_id->handler_mutex); rdma_destroy_id(new_cm_id); goto out; } ret = rdma_copy_addr(&conn_id->id.route.addr.dev_addr, dev, NULL); if (ret) { - cma_enable_remove(conn_id); + mutex_unlock(&conn_id->handler_mutex); rdma_destroy_id(new_cm_id); goto out; } @@ -1321,7 +1308,7 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id, ret = cma_acquire_dev(conn_id); mutex_unlock(&lock); if (ret) { - cma_enable_remove(conn_id); + mutex_unlock(&conn_id->handler_mutex); rdma_destroy_id(new_cm_id); goto out; } @@ -1337,7 +1324,7 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id, ret = ib_query_device(conn_id->id.device, &attr); if (ret) { - cma_enable_remove(conn_id); + mutex_unlock(&conn_id->handler_mutex); rdma_destroy_id(new_cm_id); goto out; } @@ -1353,14 +1340,17 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id, /* User wants to destroy the CM ID */ conn_id->cm_id.iw = NULL; cma_exch(conn_id, CMA_DESTROYING); - cma_enable_remove(conn_id); + mutex_unlock(&conn_id->handler_mutex); rdma_destroy_id(&conn_id->id); + goto out; } + mutex_unlock(&conn_id->handler_mutex); + out: if (dev) dev_put(dev); - cma_enable_remove(listen_id); + mutex_unlock(&listen_id->handler_mutex); return ret; } @@ -1592,7 +1582,7 @@ static void cma_work_handler(struct work_struct *_work) struct rdma_id_private *id_priv = work->id; int destroy = 0; - atomic_inc(&id_priv->dev_remove); + mutex_lock(&id_priv->handler_mutex); if (!cma_comp_exch(id_priv, work->old_state, work->new_state)) goto out; @@ -1601,7 +1591,7 @@ static void cma_work_handler(struct work_struct *_work) destroy = 1; } out: - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); cma_deref_id(id_priv); if (destroy) rdma_destroy_id(&id_priv->id); @@ -1764,7 +1754,7 @@ static void addr_handler(int status, struct sockaddr *src_addr, struct rdma_cm_event event; memset(&event, 0, sizeof event); - atomic_inc(&id_priv->dev_remove); + mutex_lock(&id_priv->handler_mutex); /* * Grab mutex to block rdma_destroy_id() from removing the device while @@ -1793,13 +1783,13 @@ static void addr_handler(int status, struct sockaddr *src_addr, if (id_priv->id.event_handler(&id_priv->id, &event)) { cma_exch(id_priv, CMA_DESTROYING); - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); cma_deref_id(id_priv); rdma_destroy_id(&id_priv->id); return; } out: - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); cma_deref_id(id_priv); } @@ -2126,7 +2116,7 @@ static int cma_sidr_rep_handler(struct ib_cm_id *cm_id, struct ib_cm_sidr_rep_event_param *rep = &ib_event->param.sidr_rep_rcvd; int ret = 0; - if (cma_disable_remove(id_priv, CMA_CONNECT)) + if (cma_disable_callback(id_priv, CMA_CONNECT)) return 0; memset(&event, 0, sizeof event); @@ -2167,12 +2157,12 @@ static int cma_sidr_rep_handler(struct ib_cm_id *cm_id, /* Destroy the CM ID by returning a non-zero value. */ id_priv->cm_id.ib = NULL; cma_exch(id_priv, CMA_DESTROYING); - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); rdma_destroy_id(&id_priv->id); return ret; } out: - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); return ret; } @@ -2570,8 +2560,8 @@ static int cma_ib_mc_handler(int status, struct ib_sa_multicast *multicast) int ret; id_priv = mc->id_priv; - if (cma_disable_remove(id_priv, CMA_ADDR_BOUND) && - cma_disable_remove(id_priv, CMA_ADDR_RESOLVED)) + if (cma_disable_callback(id_priv, CMA_ADDR_BOUND) && + cma_disable_callback(id_priv, CMA_ADDR_RESOLVED)) return 0; mutex_lock(&id_priv->qp_mutex); @@ -2596,12 +2586,12 @@ static int cma_ib_mc_handler(int status, struct ib_sa_multicast *multicast) ret = id_priv->id.event_handler(&id_priv->id, &event); if (ret) { cma_exch(id_priv, CMA_DESTROYING); - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); rdma_destroy_id(&id_priv->id); return 0; } - cma_enable_remove(id_priv); + mutex_unlock(&id_priv->handler_mutex); return 0; } @@ -2760,6 +2750,7 @@ static int cma_remove_id_dev(struct rdma_id_private *id_priv) { struct rdma_cm_event event; enum cma_state state; + int ret = 0; /* Record that we want to remove the device */ state = cma_exch(id_priv, CMA_DEVICE_REMOVAL); @@ -2767,15 +2758,18 @@ static int cma_remove_id_dev(struct rdma_id_private *id_priv) return 0; cma_cancel_operation(id_priv, state); - wait_event(id_priv->wait_remove, !atomic_read(&id_priv->dev_remove)); + mutex_lock(&id_priv->handler_mutex); /* Check for destruction from another callback. */ if (!cma_comp(id_priv, CMA_DEVICE_REMOVAL)) - return 0; + goto out; memset(&event, 0, sizeof event); event.event = RDMA_CM_EVENT_DEVICE_REMOVAL; - return id_priv->id.event_handler(&id_priv->id, &event); + ret = id_priv->id.event_handler(&id_priv->id, &event); +out: + mutex_unlock(&id_priv->handler_mutex); + return ret; } static void cma_process_remove(struct cma_device *cma_dev) -- cgit v1.2.3