diff options
Diffstat (limited to 'drivers/misc/mic/scif/scif_api.c')
| -rw-r--r-- | drivers/misc/mic/scif/scif_api.c | 457 |
1 files changed, 457 insertions, 0 deletions
diff --git a/drivers/misc/mic/scif/scif_api.c b/drivers/misc/mic/scif/scif_api.c index cbdc27b3b187..da64cee91908 100644 --- a/drivers/misc/mic/scif/scif_api.c +++ b/drivers/misc/mic/scif/scif_api.c @@ -415,3 +415,460 @@ int scif_listen(scif_epd_t epd, int backlog) return 0; } EXPORT_SYMBOL_GPL(scif_listen); + +/* + ************************************************************************ + * SCIF connection flow: + * + * 1) A SCIF listening endpoint can call scif_accept(..) to wait for SCIF + * connections via a SCIF_CNCT_REQ message + * 2) A SCIF endpoint can initiate a SCIF connection by calling + * scif_connect(..) which calls scif_setup_qp_connect(..) which + * allocates the local qp for the endpoint ring buffer and then sends + * a SCIF_CNCT_REQ to the remote node and waits for a SCIF_CNCT_GNT or + * a SCIF_CNCT_REJ message + * 3) The peer node handles a SCIF_CNCT_REQ via scif_cnctreq_resp(..) which + * wakes up any threads blocked in step 1 or sends a SCIF_CNCT_REJ + * message otherwise + * 4) A thread blocked waiting for incoming connections allocates its local + * endpoint QP and ring buffer following which it sends a SCIF_CNCT_GNT + * and waits for a SCIF_CNCT_GNT(N)ACK. If the allocation fails then + * the node sends a SCIF_CNCT_REJ message + * 5) Upon receipt of a SCIF_CNCT_GNT or a SCIF_CNCT_REJ message the + * connecting endpoint is woken up as part of handling + * scif_cnctgnt_resp(..) following which it maps the remote endpoints' + * QP, updates its outbound QP and sends a SCIF_CNCT_GNTACK message on + * success or a SCIF_CNCT_GNTNACK message on failure and completes + * the scif_connect(..) API + * 6) Upon receipt of a SCIF_CNCT_GNT(N)ACK the accepting endpoint blocked + * in step 4 is woken up and completes the scif_accept(..) API + * 7) The SCIF connection is now established between the two SCIF endpoints. + */ +static int scif_conn_func(struct scif_endpt *ep) +{ + int err = 0; + struct scifmsg msg; + struct device *spdev; + + /* Initiate the first part of the endpoint QP setup */ + err = scif_setup_qp_connect(ep->qp_info.qp, &ep->qp_info.qp_offset, + SCIF_ENDPT_QP_SIZE, ep->remote_dev); + if (err) { + dev_err(&ep->remote_dev->sdev->dev, + "%s err %d qp_offset 0x%llx\n", + __func__, err, ep->qp_info.qp_offset); + ep->state = SCIFEP_BOUND; + goto connect_error_simple; + } + + spdev = scif_get_peer_dev(ep->remote_dev); + if (IS_ERR(spdev)) { + err = PTR_ERR(spdev); + goto cleanup_qp; + } + /* Format connect message and send it */ + msg.src = ep->port; + msg.dst = ep->conn_port; + msg.uop = SCIF_CNCT_REQ; + msg.payload[0] = (u64)ep; + msg.payload[1] = ep->qp_info.qp_offset; + err = _scif_nodeqp_send(ep->remote_dev, &msg); + if (err) + goto connect_error_dec; + scif_put_peer_dev(spdev); + /* + * Wait for the remote node to respond with SCIF_CNCT_GNT or + * SCIF_CNCT_REJ message. + */ + err = wait_event_timeout(ep->conwq, ep->state != SCIFEP_CONNECTING, + SCIF_NODE_ALIVE_TIMEOUT); + if (!err) { + dev_err(&ep->remote_dev->sdev->dev, + "%s %d timeout\n", __func__, __LINE__); + ep->state = SCIFEP_BOUND; + } + spdev = scif_get_peer_dev(ep->remote_dev); + if (IS_ERR(spdev)) { + err = PTR_ERR(spdev); + goto cleanup_qp; + } + if (ep->state == SCIFEP_MAPPING) { + err = scif_setup_qp_connect_response(ep->remote_dev, + ep->qp_info.qp, + ep->qp_info.gnt_pld); + /* + * If the resource to map the queue are not available then + * we need to tell the other side to terminate the accept + */ + if (err) { + dev_err(&ep->remote_dev->sdev->dev, + "%s %d err %d\n", __func__, __LINE__, err); + msg.uop = SCIF_CNCT_GNTNACK; + msg.payload[0] = ep->remote_ep; + _scif_nodeqp_send(ep->remote_dev, &msg); + ep->state = SCIFEP_BOUND; + goto connect_error_dec; + } + + msg.uop = SCIF_CNCT_GNTACK; + msg.payload[0] = ep->remote_ep; + err = _scif_nodeqp_send(ep->remote_dev, &msg); + if (err) { + ep->state = SCIFEP_BOUND; + goto connect_error_dec; + } + ep->state = SCIFEP_CONNECTED; + mutex_lock(&scif_info.connlock); + list_add_tail(&ep->list, &scif_info.connected); + mutex_unlock(&scif_info.connlock); + dev_dbg(&ep->remote_dev->sdev->dev, + "SCIFAPI connect: ep %p connected\n", ep); + } else if (ep->state == SCIFEP_BOUND) { + dev_dbg(&ep->remote_dev->sdev->dev, + "SCIFAPI connect: ep %p connection refused\n", ep); + err = -ECONNREFUSED; + goto connect_error_dec; + } + scif_put_peer_dev(spdev); + return err; +connect_error_dec: + scif_put_peer_dev(spdev); +cleanup_qp: + scif_cleanup_ep_qp(ep); +connect_error_simple: + return err; +} + +/* + * scif_conn_handler: + * + * Workqueue handler for servicing non-blocking SCIF connect + * + */ +void scif_conn_handler(struct work_struct *work) +{ + struct scif_endpt *ep; + + do { + ep = NULL; + spin_lock(&scif_info.nb_connect_lock); + if (!list_empty(&scif_info.nb_connect_list)) { + ep = list_first_entry(&scif_info.nb_connect_list, + struct scif_endpt, conn_list); + list_del(&ep->conn_list); + } + spin_unlock(&scif_info.nb_connect_lock); + if (ep) + ep->conn_err = scif_conn_func(ep); + } while (ep); +} + +int __scif_connect(scif_epd_t epd, struct scif_port_id *dst, bool non_block) +{ + struct scif_endpt *ep = (struct scif_endpt *)epd; + int err = 0; + struct scif_dev *remote_dev; + struct device *spdev; + + dev_dbg(scif_info.mdev.this_device, "SCIFAPI connect: ep %p %s\n", ep, + scif_ep_states[ep->state]); + + if (!scif_dev || dst->node > scif_info.maxid) + return -ENODEV; + + might_sleep(); + + remote_dev = &scif_dev[dst->node]; + spdev = scif_get_peer_dev(remote_dev); + if (IS_ERR(spdev)) { + err = PTR_ERR(spdev); + return err; + } + + spin_lock(&ep->lock); + switch (ep->state) { + case SCIFEP_ZOMBIE: + case SCIFEP_CLOSING: + err = -EINVAL; + break; + case SCIFEP_DISCONNECTED: + if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) + ep->conn_async_state = ASYNC_CONN_FLUSH_WORK; + else + err = -EINVAL; + break; + case SCIFEP_LISTENING: + case SCIFEP_CLLISTEN: + err = -EOPNOTSUPP; + break; + case SCIFEP_CONNECTING: + case SCIFEP_MAPPING: + if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) + err = -EINPROGRESS; + else + err = -EISCONN; + break; + case SCIFEP_CONNECTED: + if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) + ep->conn_async_state = ASYNC_CONN_FLUSH_WORK; + else + err = -EISCONN; + break; + case SCIFEP_UNBOUND: + ep->port.port = scif_get_new_port(); + if (!ep->port.port) { + err = -ENOSPC; + } else { + ep->port.node = scif_info.nodeid; + ep->conn_async_state = ASYNC_CONN_IDLE; + } + /* Fall through */ + case SCIFEP_BOUND: + /* + * If a non-blocking connect has been already initiated + * (conn_async_state is either ASYNC_CONN_INPROGRESS or + * ASYNC_CONN_FLUSH_WORK), the end point could end up in + * SCIF_BOUND due an error in the connection process + * (e.g., connection refused) If conn_async_state is + * ASYNC_CONN_INPROGRESS - transition to ASYNC_CONN_FLUSH_WORK + * so that the error status can be collected. If the state is + * already ASYNC_CONN_FLUSH_WORK - then set the error to + * EINPROGRESS since some other thread is waiting to collect + * error status. + */ + if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) { + ep->conn_async_state = ASYNC_CONN_FLUSH_WORK; + } else if (ep->conn_async_state == ASYNC_CONN_FLUSH_WORK) { + err = -EINPROGRESS; + } else { + ep->conn_port = *dst; + init_waitqueue_head(&ep->sendwq); + init_waitqueue_head(&ep->recvwq); + init_waitqueue_head(&ep->conwq); + ep->conn_async_state = 0; + + if (unlikely(non_block)) + ep->conn_async_state = ASYNC_CONN_INPROGRESS; + } + break; + } + + if (err || ep->conn_async_state == ASYNC_CONN_FLUSH_WORK) + goto connect_simple_unlock1; + + ep->state = SCIFEP_CONNECTING; + ep->remote_dev = &scif_dev[dst->node]; + ep->qp_info.qp->magic = SCIFEP_MAGIC; + if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) { + spin_lock(&scif_info.nb_connect_lock); + list_add_tail(&ep->conn_list, &scif_info.nb_connect_list); + spin_unlock(&scif_info.nb_connect_lock); + err = -EINPROGRESS; + schedule_work(&scif_info.conn_work); + } +connect_simple_unlock1: + spin_unlock(&ep->lock); + scif_put_peer_dev(spdev); + if (err) { + return err; + } else if (ep->conn_async_state == ASYNC_CONN_FLUSH_WORK) { + flush_work(&scif_info.conn_work); + err = ep->conn_err; + spin_lock(&ep->lock); + ep->conn_async_state = ASYNC_CONN_IDLE; + spin_unlock(&ep->lock); + } else { + err = scif_conn_func(ep); + } + return err; +} + +int scif_connect(scif_epd_t epd, struct scif_port_id *dst) +{ + return __scif_connect(epd, dst, false); +} +EXPORT_SYMBOL_GPL(scif_connect); + +/** + * scif_accept() - Accept a connection request from the remote node + * + * The function accepts a connection request from the remote node. Successful + * complete is indicate by a new end point being created and passed back + * to the caller for future reference. + * + * Upon successful complete a zero will be returned and the peer information + * will be filled in. + * + * If the end point is not in the listening state -EINVAL will be returned. + * + * If during the connection sequence resource allocation fails the -ENOMEM + * will be returned. + * + * If the function is called with the ASYNC flag set and no connection requests + * are pending it will return -EAGAIN. + * + * If the remote side is not sending any connection requests the caller may + * terminate this function with a signal. If so a -EINTR will be returned. + */ +int scif_accept(scif_epd_t epd, struct scif_port_id *peer, + scif_epd_t *newepd, int flags) +{ + struct scif_endpt *lep = (struct scif_endpt *)epd; + struct scif_endpt *cep; + struct scif_conreq *conreq; + struct scifmsg msg; + int err; + struct device *spdev; + + dev_dbg(scif_info.mdev.this_device, + "SCIFAPI accept: ep %p %s\n", lep, scif_ep_states[lep->state]); + + if (flags & ~SCIF_ACCEPT_SYNC) + return -EINVAL; + + if (!peer || !newepd) + return -EINVAL; + + might_sleep(); + spin_lock(&lep->lock); + if (lep->state != SCIFEP_LISTENING) { + spin_unlock(&lep->lock); + return -EINVAL; + } + + if (!lep->conreqcnt && !(flags & SCIF_ACCEPT_SYNC)) { + /* No connection request present and we do not want to wait */ + spin_unlock(&lep->lock); + return -EAGAIN; + } + + lep->files = current->files; +retry_connection: + spin_unlock(&lep->lock); + /* Wait for the remote node to send us a SCIF_CNCT_REQ */ + err = wait_event_interruptible(lep->conwq, + (lep->conreqcnt || + (lep->state != SCIFEP_LISTENING))); + if (err) + return err; + + if (lep->state != SCIFEP_LISTENING) + return -EINTR; + + spin_lock(&lep->lock); + + if (!lep->conreqcnt) + goto retry_connection; + + /* Get the first connect request off the list */ + conreq = list_first_entry(&lep->conlist, struct scif_conreq, list); + list_del(&conreq->list); + lep->conreqcnt--; + spin_unlock(&lep->lock); + + /* Fill in the peer information */ + peer->node = conreq->msg.src.node; + peer->port = conreq->msg.src.port; + + cep = kzalloc(sizeof(*cep), GFP_KERNEL); + if (!cep) { + err = -ENOMEM; + goto scif_accept_error_epalloc; + } + spin_lock_init(&cep->lock); + mutex_init(&cep->sendlock); + mutex_init(&cep->recvlock); + cep->state = SCIFEP_CONNECTING; + cep->remote_dev = &scif_dev[peer->node]; + cep->remote_ep = conreq->msg.payload[0]; + + cep->qp_info.qp = kzalloc(sizeof(*cep->qp_info.qp), GFP_KERNEL); + if (!cep->qp_info.qp) { + err = -ENOMEM; + goto scif_accept_error_qpalloc; + } + + cep->qp_info.qp->magic = SCIFEP_MAGIC; + spdev = scif_get_peer_dev(cep->remote_dev); + if (IS_ERR(spdev)) { + err = PTR_ERR(spdev); + goto scif_accept_error_map; + } + err = scif_setup_qp_accept(cep->qp_info.qp, &cep->qp_info.qp_offset, + conreq->msg.payload[1], SCIF_ENDPT_QP_SIZE, + cep->remote_dev); + if (err) { + dev_dbg(&cep->remote_dev->sdev->dev, + "SCIFAPI accept: ep %p new %p scif_setup_qp_accept %d qp_offset 0x%llx\n", + lep, cep, err, cep->qp_info.qp_offset); + scif_put_peer_dev(spdev); + goto scif_accept_error_map; + } + + cep->port.node = lep->port.node; + cep->port.port = lep->port.port; + cep->peer.node = peer->node; + cep->peer.port = peer->port; + init_waitqueue_head(&cep->sendwq); + init_waitqueue_head(&cep->recvwq); + init_waitqueue_head(&cep->conwq); + + msg.uop = SCIF_CNCT_GNT; + msg.src = cep->port; + msg.payload[0] = cep->remote_ep; + msg.payload[1] = cep->qp_info.qp_offset; + msg.payload[2] = (u64)cep; + + err = _scif_nodeqp_send(cep->remote_dev, &msg); + scif_put_peer_dev(spdev); + if (err) + goto scif_accept_error_map; +retry: + /* Wait for the remote node to respond with SCIF_CNCT_GNT(N)ACK */ + err = wait_event_timeout(cep->conwq, cep->state != SCIFEP_CONNECTING, + SCIF_NODE_ACCEPT_TIMEOUT); + if (!err && scifdev_alive(cep)) + goto retry; + err = !err ? -ENODEV : 0; + if (err) + goto scif_accept_error_map; + kfree(conreq); + + spin_lock(&cep->lock); + + if (cep->state == SCIFEP_CLOSING) { + /* + * Remote failed to allocate resources and NAKed the grant. + * There is at this point nothing referencing the new end point. + */ + spin_unlock(&cep->lock); + scif_teardown_ep(cep); + kfree(cep); + + /* If call with sync flag then go back and wait. */ + if (flags & SCIF_ACCEPT_SYNC) { + spin_lock(&lep->lock); + goto retry_connection; + } + return -EAGAIN; + } + + scif_get_port(cep->port.port); + *newepd = (scif_epd_t)cep; + spin_unlock(&cep->lock); + return 0; +scif_accept_error_map: + scif_teardown_ep(cep); +scif_accept_error_qpalloc: + kfree(cep); +scif_accept_error_epalloc: + msg.uop = SCIF_CNCT_REJ; + msg.dst.node = conreq->msg.src.node; + msg.dst.port = conreq->msg.src.port; + msg.payload[0] = conreq->msg.payload[0]; + msg.payload[1] = conreq->msg.payload[1]; + scif_nodeqp_send(&scif_dev[conreq->msg.src.node], &msg); + kfree(conreq); + return err; +} +EXPORT_SYMBOL_GPL(scif_accept); |