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 <ogerlitz@voltaire.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>hifive-unleashed-5.1
Or Gerlitz
Roland Dreier
parent
64c5e613b9
commit
de910bd921
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@ -130,8 +130,7 @@ struct rdma_id_private {
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struct completion comp;
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atomic_t refcount;
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wait_queue_head_t wait_remove;
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atomic_t dev_remove;
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struct mutex handler_mutex;
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int backlog;
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int timeout_ms;
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@ -355,26 +354,15 @@ static void cma_deref_id(struct rdma_id_private *id_priv)
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complete(&id_priv->comp);
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}
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static int cma_disable_remove(struct rdma_id_private *id_priv,
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static int cma_disable_callback(struct rdma_id_private *id_priv,
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enum cma_state state)
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{
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unsigned long flags;
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int ret;
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spin_lock_irqsave(&id_priv->lock, flags);
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if (id_priv->state == state) {
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atomic_inc(&id_priv->dev_remove);
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ret = 0;
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} else
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ret = -EINVAL;
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spin_unlock_irqrestore(&id_priv->lock, flags);
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return ret;
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}
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static void cma_enable_remove(struct rdma_id_private *id_priv)
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{
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if (atomic_dec_and_test(&id_priv->dev_remove))
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wake_up(&id_priv->wait_remove);
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mutex_lock(&id_priv->handler_mutex);
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if (id_priv->state != state) {
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mutex_unlock(&id_priv->handler_mutex);
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return -EINVAL;
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}
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return 0;
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}
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static int cma_has_cm_dev(struct rdma_id_private *id_priv)
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@ -399,8 +387,7 @@ struct rdma_cm_id *rdma_create_id(rdma_cm_event_handler event_handler,
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mutex_init(&id_priv->qp_mutex);
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init_completion(&id_priv->comp);
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atomic_set(&id_priv->refcount, 1);
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init_waitqueue_head(&id_priv->wait_remove);
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atomic_set(&id_priv->dev_remove, 0);
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mutex_init(&id_priv->handler_mutex);
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INIT_LIST_HEAD(&id_priv->listen_list);
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INIT_LIST_HEAD(&id_priv->mc_list);
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get_random_bytes(&id_priv->seq_num, sizeof id_priv->seq_num);
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@ -927,7 +914,7 @@ static int cma_ib_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event)
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struct rdma_cm_event event;
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int ret = 0;
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if (cma_disable_remove(id_priv, CMA_CONNECT))
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if (cma_disable_callback(id_priv, CMA_CONNECT))
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return 0;
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memset(&event, 0, sizeof event);
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@ -984,12 +971,12 @@ static int cma_ib_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event)
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/* Destroy the CM ID by returning a non-zero value. */
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id_priv->cm_id.ib = NULL;
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cma_exch(id_priv, CMA_DESTROYING);
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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rdma_destroy_id(&id_priv->id);
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return ret;
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}
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out:
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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return ret;
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}
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@ -1101,7 +1088,7 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event)
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int offset, ret;
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listen_id = cm_id->context;
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if (cma_disable_remove(listen_id, CMA_LISTEN))
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if (cma_disable_callback(listen_id, CMA_LISTEN))
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return -ECONNABORTED;
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memset(&event, 0, sizeof event);
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@ -1122,7 +1109,7 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event)
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goto out;
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}
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atomic_inc(&conn_id->dev_remove);
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mutex_lock_nested(&conn_id->handler_mutex, SINGLE_DEPTH_NESTING);
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mutex_lock(&lock);
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ret = cma_acquire_dev(conn_id);
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mutex_unlock(&lock);
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@ -1144,7 +1131,7 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event)
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!cma_is_ud_ps(conn_id->id.ps))
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ib_send_cm_mra(cm_id, CMA_CM_MRA_SETTING, NULL, 0);
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mutex_unlock(&lock);
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cma_enable_remove(conn_id);
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mutex_unlock(&conn_id->handler_mutex);
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goto out;
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}
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@ -1153,11 +1140,11 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event)
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release_conn_id:
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cma_exch(conn_id, CMA_DESTROYING);
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cma_enable_remove(conn_id);
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mutex_unlock(&conn_id->handler_mutex);
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rdma_destroy_id(&conn_id->id);
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out:
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cma_enable_remove(listen_id);
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mutex_unlock(&listen_id->handler_mutex);
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return ret;
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}
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@ -1223,7 +1210,7 @@ static int cma_iw_handler(struct iw_cm_id *iw_id, struct iw_cm_event *iw_event)
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struct sockaddr_in *sin;
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int ret = 0;
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if (cma_disable_remove(id_priv, CMA_CONNECT))
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if (cma_disable_callback(id_priv, CMA_CONNECT))
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return 0;
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memset(&event, 0, sizeof event);
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@ -1267,12 +1254,12 @@ static int cma_iw_handler(struct iw_cm_id *iw_id, struct iw_cm_event *iw_event)
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/* Destroy the CM ID by returning a non-zero value. */
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id_priv->cm_id.iw = NULL;
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cma_exch(id_priv, CMA_DESTROYING);
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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rdma_destroy_id(&id_priv->id);
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return ret;
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}
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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return ret;
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}
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@ -1288,7 +1275,7 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id,
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struct ib_device_attr attr;
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listen_id = cm_id->context;
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if (cma_disable_remove(listen_id, CMA_LISTEN))
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if (cma_disable_callback(listen_id, CMA_LISTEN))
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return -ECONNABORTED;
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/* Create a new RDMA id for the new IW CM ID */
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@ -1300,19 +1287,19 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id,
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goto out;
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}
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conn_id = container_of(new_cm_id, struct rdma_id_private, id);
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atomic_inc(&conn_id->dev_remove);
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mutex_lock_nested(&conn_id->handler_mutex, SINGLE_DEPTH_NESTING);
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conn_id->state = CMA_CONNECT;
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dev = ip_dev_find(&init_net, iw_event->local_addr.sin_addr.s_addr);
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if (!dev) {
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ret = -EADDRNOTAVAIL;
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cma_enable_remove(conn_id);
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mutex_unlock(&conn_id->handler_mutex);
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rdma_destroy_id(new_cm_id);
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goto out;
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}
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ret = rdma_copy_addr(&conn_id->id.route.addr.dev_addr, dev, NULL);
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if (ret) {
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cma_enable_remove(conn_id);
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mutex_unlock(&conn_id->handler_mutex);
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rdma_destroy_id(new_cm_id);
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goto out;
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}
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@ -1321,7 +1308,7 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id,
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ret = cma_acquire_dev(conn_id);
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mutex_unlock(&lock);
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if (ret) {
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cma_enable_remove(conn_id);
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mutex_unlock(&conn_id->handler_mutex);
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rdma_destroy_id(new_cm_id);
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goto out;
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}
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@ -1337,7 +1324,7 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id,
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ret = ib_query_device(conn_id->id.device, &attr);
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if (ret) {
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cma_enable_remove(conn_id);
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mutex_unlock(&conn_id->handler_mutex);
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rdma_destroy_id(new_cm_id);
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goto out;
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}
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@ -1353,14 +1340,17 @@ static int iw_conn_req_handler(struct iw_cm_id *cm_id,
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/* User wants to destroy the CM ID */
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conn_id->cm_id.iw = NULL;
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cma_exch(conn_id, CMA_DESTROYING);
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cma_enable_remove(conn_id);
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mutex_unlock(&conn_id->handler_mutex);
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rdma_destroy_id(&conn_id->id);
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goto out;
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}
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mutex_unlock(&conn_id->handler_mutex);
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out:
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if (dev)
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dev_put(dev);
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cma_enable_remove(listen_id);
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mutex_unlock(&listen_id->handler_mutex);
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return ret;
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}
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@ -1592,7 +1582,7 @@ static void cma_work_handler(struct work_struct *_work)
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struct rdma_id_private *id_priv = work->id;
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int destroy = 0;
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atomic_inc(&id_priv->dev_remove);
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mutex_lock(&id_priv->handler_mutex);
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if (!cma_comp_exch(id_priv, work->old_state, work->new_state))
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goto out;
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@ -1601,7 +1591,7 @@ static void cma_work_handler(struct work_struct *_work)
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destroy = 1;
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}
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out:
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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cma_deref_id(id_priv);
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if (destroy)
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rdma_destroy_id(&id_priv->id);
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@ -1764,7 +1754,7 @@ static void addr_handler(int status, struct sockaddr *src_addr,
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struct rdma_cm_event event;
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memset(&event, 0, sizeof event);
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atomic_inc(&id_priv->dev_remove);
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mutex_lock(&id_priv->handler_mutex);
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/*
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* Grab mutex to block rdma_destroy_id() from removing the device while
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@ -1793,13 +1783,13 @@ static void addr_handler(int status, struct sockaddr *src_addr,
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if (id_priv->id.event_handler(&id_priv->id, &event)) {
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cma_exch(id_priv, CMA_DESTROYING);
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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cma_deref_id(id_priv);
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rdma_destroy_id(&id_priv->id);
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return;
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}
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out:
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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cma_deref_id(id_priv);
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}
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@ -2126,7 +2116,7 @@ static int cma_sidr_rep_handler(struct ib_cm_id *cm_id,
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struct ib_cm_sidr_rep_event_param *rep = &ib_event->param.sidr_rep_rcvd;
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int ret = 0;
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if (cma_disable_remove(id_priv, CMA_CONNECT))
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if (cma_disable_callback(id_priv, CMA_CONNECT))
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return 0;
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memset(&event, 0, sizeof event);
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@ -2167,12 +2157,12 @@ static int cma_sidr_rep_handler(struct ib_cm_id *cm_id,
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/* Destroy the CM ID by returning a non-zero value. */
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id_priv->cm_id.ib = NULL;
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cma_exch(id_priv, CMA_DESTROYING);
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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rdma_destroy_id(&id_priv->id);
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return ret;
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}
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out:
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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return ret;
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}
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@ -2570,8 +2560,8 @@ static int cma_ib_mc_handler(int status, struct ib_sa_multicast *multicast)
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int ret;
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id_priv = mc->id_priv;
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if (cma_disable_remove(id_priv, CMA_ADDR_BOUND) &&
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cma_disable_remove(id_priv, CMA_ADDR_RESOLVED))
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if (cma_disable_callback(id_priv, CMA_ADDR_BOUND) &&
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cma_disable_callback(id_priv, CMA_ADDR_RESOLVED))
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return 0;
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mutex_lock(&id_priv->qp_mutex);
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@ -2596,12 +2586,12 @@ static int cma_ib_mc_handler(int status, struct ib_sa_multicast *multicast)
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ret = id_priv->id.event_handler(&id_priv->id, &event);
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if (ret) {
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cma_exch(id_priv, CMA_DESTROYING);
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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rdma_destroy_id(&id_priv->id);
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return 0;
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}
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cma_enable_remove(id_priv);
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mutex_unlock(&id_priv->handler_mutex);
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return 0;
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}
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@ -2760,6 +2750,7 @@ static int cma_remove_id_dev(struct rdma_id_private *id_priv)
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{
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struct rdma_cm_event event;
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enum cma_state state;
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int ret = 0;
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/* Record that we want to remove the device */
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state = cma_exch(id_priv, CMA_DEVICE_REMOVAL);
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@ -2767,15 +2758,18 @@ static int cma_remove_id_dev(struct rdma_id_private *id_priv)
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return 0;
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cma_cancel_operation(id_priv, state);
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wait_event(id_priv->wait_remove, !atomic_read(&id_priv->dev_remove));
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mutex_lock(&id_priv->handler_mutex);
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/* Check for destruction from another callback. */
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if (!cma_comp(id_priv, CMA_DEVICE_REMOVAL))
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return 0;
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goto out;
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memset(&event, 0, sizeof event);
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event.event = RDMA_CM_EVENT_DEVICE_REMOVAL;
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return id_priv->id.event_handler(&id_priv->id, &event);
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ret = id_priv->id.event_handler(&id_priv->id, &event);
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out:
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mutex_unlock(&id_priv->handler_mutex);
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return ret;
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}
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static void cma_process_remove(struct cma_device *cma_dev)
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