/****************************************************************************** ******************************************************************************* ** ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. ** Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. ** ** This copyrighted material is made available to anyone wishing to use, ** modify, copy, or redistribute it subject to the terms and conditions ** of the GNU General Public License v.2. ** ******************************************************************************* ******************************************************************************/ /* * lowcomms.c * * This is the "low-level" comms layer. * * It is responsible for sending/receiving messages * from other nodes in the cluster. * * Cluster nodes are referred to by their nodeids. nodeids are * simply 32 bit numbers to the locking module - if they need to * be expanded for the cluster infrastructure then that is it's * responsibility. It is this layer's * responsibility to resolve these into IP address or * whatever it needs for inter-node communication. * * The comms level is two kernel threads that deal mainly with * the receiving of messages from other nodes and passing them * up to the mid-level comms layer (which understands the * message format) for execution by the locking core, and * a send thread which does all the setting up of connections * to remote nodes and the sending of data. Threads are not allowed * to send their own data because it may cause them to wait in times * of high load. Also, this way, the sending thread can collect together * messages bound for one node and send them in one block. * * I don't see any problem with the recv thread executing the locking * code on behalf of remote processes as the locking code is * short, efficient and never waits. * */ #include #include #include #include #include "dlm_internal.h" #include "lowcomms.h" #include "midcomms.h" #include "config.h" struct cbuf { unsigned int base; unsigned int len; unsigned int mask; }; #define NODE_INCREMENT 32 static void cbuf_add(struct cbuf *cb, int n) { cb->len += n; } static int cbuf_data(struct cbuf *cb) { return ((cb->base + cb->len) & cb->mask); } static void cbuf_init(struct cbuf *cb, int size) { cb->base = cb->len = 0; cb->mask = size-1; } static void cbuf_eat(struct cbuf *cb, int n) { cb->len -= n; cb->base += n; cb->base &= cb->mask; } static bool cbuf_empty(struct cbuf *cb) { return cb->len == 0; } /* Maximum number of incoming messages to process before doing a cond_resched() */ #define MAX_RX_MSG_COUNT 25 struct connection { struct socket *sock; /* NULL if not connected */ uint32_t nodeid; /* So we know who we are in the list */ struct rw_semaphore sock_sem; /* Stop connect races */ struct list_head read_list; /* On this list when ready for reading */ struct list_head write_list; /* On this list when ready for writing */ struct list_head state_list; /* On this list when ready to connect */ unsigned long flags; /* bit 1,2 = We are on the read/write lists */ #define CF_READ_PENDING 1 #define CF_WRITE_PENDING 2 #define CF_CONNECT_PENDING 3 #define CF_IS_OTHERCON 4 struct list_head writequeue; /* List of outgoing writequeue_entries */ struct list_head listenlist; /* List of allocated listening sockets */ spinlock_t writequeue_lock; int (*rx_action) (struct connection *); /* What to do when active */ struct page *rx_page; struct cbuf cb; int retries; atomic_t waiting_requests; #define MAX_CONNECT_RETRIES 3 struct connection *othercon; }; #define sock2con(x) ((struct connection *)(x)->sk_user_data) /* An entry waiting to be sent */ struct writequeue_entry { struct list_head list; struct page *page; int offset; int len; int end; int users; struct connection *con; }; static struct sockaddr_storage dlm_local_addr; /* Manage daemons */ static struct task_struct *recv_task; static struct task_struct *send_task; static wait_queue_t lowcomms_send_waitq_head; static DECLARE_WAIT_QUEUE_HEAD(lowcomms_send_waitq); static wait_queue_t lowcomms_recv_waitq_head; static DECLARE_WAIT_QUEUE_HEAD(lowcomms_recv_waitq); /* An array of pointers to connections, indexed by NODEID */ static struct connection **connections; static DECLARE_MUTEX(connections_lock); static struct kmem_cache *con_cache; static int conn_array_size; /* List of sockets that have reads pending */ static LIST_HEAD(read_sockets); static DEFINE_SPINLOCK(read_sockets_lock); /* List of sockets which have writes pending */ static LIST_HEAD(write_sockets); static DEFINE_SPINLOCK(write_sockets_lock); /* List of sockets which have connects pending */ static LIST_HEAD(state_sockets); static DEFINE_SPINLOCK(state_sockets_lock); static struct connection *nodeid2con(int nodeid, gfp_t allocation) { struct connection *con = NULL; down(&connections_lock); if (nodeid >= conn_array_size) { int new_size = nodeid + NODE_INCREMENT; struct connection **new_conns; new_conns = kzalloc(sizeof(struct connection *) * new_size, allocation); if (!new_conns) goto finish; memcpy(new_conns, connections, sizeof(struct connection *) * conn_array_size); conn_array_size = new_size; kfree(connections); connections = new_conns; } con = connections[nodeid]; if (con == NULL && allocation) { con = kmem_cache_zalloc(con_cache, allocation); if (!con) goto finish; con->nodeid = nodeid; init_rwsem(&con->sock_sem); INIT_LIST_HEAD(&con->writequeue); spin_lock_init(&con->writequeue_lock); connections[nodeid] = con; } finish: up(&connections_lock); return con; } /* Data available on socket or listen socket received a connect */ static void lowcomms_data_ready(struct sock *sk, int count_unused) { struct connection *con = sock2con(sk); atomic_inc(&con->waiting_requests); if (test_and_set_bit(CF_READ_PENDING, &con->flags)) return; spin_lock_bh(&read_sockets_lock); list_add_tail(&con->read_list, &read_sockets); spin_unlock_bh(&read_sockets_lock); wake_up_interruptible(&lowcomms_recv_waitq); } static void lowcomms_write_space(struct sock *sk) { struct connection *con = sock2con(sk); if (test_and_set_bit(CF_WRITE_PENDING, &con->flags)) return; spin_lock_bh(&write_sockets_lock); list_add_tail(&con->write_list, &write_sockets); spin_unlock_bh(&write_sockets_lock); wake_up_interruptible(&lowcomms_send_waitq); } static inline void lowcomms_connect_sock(struct connection *con) { if (test_and_set_bit(CF_CONNECT_PENDING, &con->flags)) return; spin_lock_bh(&state_sockets_lock); list_add_tail(&con->state_list, &state_sockets); spin_unlock_bh(&state_sockets_lock); wake_up_interruptible(&lowcomms_send_waitq); } static void lowcomms_state_change(struct sock *sk) { if (sk->sk_state == TCP_ESTABLISHED) lowcomms_write_space(sk); } /* Make a socket active */ static int add_sock(struct socket *sock, struct connection *con) { con->sock = sock; /* Install a data_ready callback */ con->sock->sk->sk_data_ready = lowcomms_data_ready; con->sock->sk->sk_write_space = lowcomms_write_space; con->sock->sk->sk_state_change = lowcomms_state_change; return 0; } /* Add the port number to an IP6 or 4 sockaddr and return the address length */ static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port, int *addr_len) { saddr->ss_family = dlm_local_addr.ss_family; if (saddr->ss_family == AF_INET) { struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr; in4_addr->sin_port = cpu_to_be16(port); *addr_len = sizeof(struct sockaddr_in); } else { struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr; in6_addr->sin6_port = cpu_to_be16(port); *addr_len = sizeof(struct sockaddr_in6); } } /* Close a remote connection and tidy up */ static void close_connection(struct connection *con, bool and_other) { down_write(&con->sock_sem); if (con->sock) { sock_release(con->sock); con->sock = NULL; } if (con->othercon && and_other) { /* Will only re-enter once. */ close_connection(con->othercon, false); } if (con->rx_page) { __free_page(con->rx_page); con->rx_page = NULL; } con->retries = 0; up_write(&con->sock_sem); } /* Data received from remote end */ static int receive_from_sock(struct connection *con) { int ret = 0; struct msghdr msg; struct iovec iov[2]; mm_segment_t fs; unsigned len; int r; int call_again_soon = 0; down_read(&con->sock_sem); if (con->sock == NULL) goto out; if (con->rx_page == NULL) { /* * This doesn't need to be atomic, but I think it should * improve performance if it is. */ con->rx_page = alloc_page(GFP_ATOMIC); if (con->rx_page == NULL) goto out_resched; cbuf_init(&con->cb, PAGE_CACHE_SIZE); } msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_iovlen = 1; msg.msg_iov = iov; msg.msg_name = NULL; msg.msg_namelen = 0; msg.msg_flags = 0; /* * iov[0] is the bit of the circular buffer between the current end * point (cb.base + cb.len) and the end of the buffer. */ iov[0].iov_len = con->cb.base - cbuf_data(&con->cb); iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb); iov[1].iov_len = 0; /* * iov[1] is the bit of the circular buffer between the start of the * buffer and the start of the currently used section (cb.base) */ if (cbuf_data(&con->cb) >= con->cb.base) { iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb); iov[1].iov_len = con->cb.base; iov[1].iov_base = page_address(con->rx_page); msg.msg_iovlen = 2; } len = iov[0].iov_len + iov[1].iov_len; fs = get_fs(); set_fs(get_ds()); r = ret = sock_recvmsg(con->sock, &msg, len, MSG_DONTWAIT | MSG_NOSIGNAL); set_fs(fs); if (ret <= 0) goto out_close; if (ret == len) call_again_soon = 1; cbuf_add(&con->cb, ret); ret = dlm_process_incoming_buffer(con->nodeid, page_address(con->rx_page), con->cb.base, con->cb.len, PAGE_CACHE_SIZE); if (ret == -EBADMSG) { printk(KERN_INFO "dlm: lowcomms: addr=%p, base=%u, len=%u, " "iov_len=%u, iov_base[0]=%p, read=%d\n", page_address(con->rx_page), con->cb.base, con->cb.len, len, iov[0].iov_base, r); } if (ret < 0) goto out_close; cbuf_eat(&con->cb, ret); if (cbuf_empty(&con->cb) && !call_again_soon) { __free_page(con->rx_page); con->rx_page = NULL; } out: if (call_again_soon) goto out_resched; up_read(&con->sock_sem); return 0; out_resched: lowcomms_data_ready(con->sock->sk, 0); up_read(&con->sock_sem); cond_resched(); return 0; out_close: up_read(&con->sock_sem); if (ret != -EAGAIN && !test_bit(CF_IS_OTHERCON, &con->flags)) { close_connection(con, false); /* Reconnect when there is something to send */ } return ret; } /* Listening socket is busy, accept a connection */ static int accept_from_sock(struct connection *con) { int result; struct sockaddr_storage peeraddr; struct socket *newsock; int len; int nodeid; struct connection *newcon; memset(&peeraddr, 0, sizeof(peeraddr)); result = sock_create_kern(dlm_local_addr.ss_family, SOCK_STREAM, IPPROTO_TCP, &newsock); if (result < 0) return -ENOMEM; down_read(&con->sock_sem); result = -ENOTCONN; if (con->sock == NULL) goto accept_err; newsock->type = con->sock->type; newsock->ops = con->sock->ops; result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK); if (result < 0) goto accept_err; /* Get the connected socket's peer */ memset(&peeraddr, 0, sizeof(peeraddr)); if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, &len, 2)) { result = -ECONNABORTED; goto accept_err; } /* Get the new node's NODEID */ make_sockaddr(&peeraddr, 0, &len); if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) { printk("dlm: connect from non cluster node\n"); sock_release(newsock); up_read(&con->sock_sem); return -1; } log_print("got connection from %d", nodeid); /* Check to see if we already have a connection to this node. This * could happen if the two nodes initiate a connection at roughly * the same time and the connections cross on the wire. * TEMPORARY FIX: * In this case we store the incoming one in "othercon" */ newcon = nodeid2con(nodeid, GFP_KERNEL); if (!newcon) { result = -ENOMEM; goto accept_err; } down_write(&newcon->sock_sem); if (newcon->sock) { struct connection *othercon = newcon->othercon; if (!othercon) { othercon = kmem_cache_zalloc(con_cache, GFP_KERNEL); if (!othercon) { printk("dlm: failed to allocate incoming socket\n"); up_write(&newcon->sock_sem); result = -ENOMEM; goto accept_err; } othercon->nodeid = nodeid; othercon->rx_action = receive_from_sock; init_rwsem(&othercon->sock_sem); set_bit(CF_IS_OTHERCON, &othercon->flags); newcon->othercon = othercon; } othercon->sock = newsock; newsock->sk->sk_user_data = othercon; add_sock(newsock, othercon); } else { newsock->sk->sk_user_data = newcon; newcon->rx_action = receive_from_sock; add_sock(newsock, newcon); } up_write(&newcon->sock_sem); /* * Add it to the active queue in case we got data * beween processing the accept adding the socket * to the read_sockets list */ lowcomms_data_ready(newsock->sk, 0); up_read(&con->sock_sem); return 0; accept_err: up_read(&con->sock_sem); sock_release(newsock); if (result != -EAGAIN) printk("dlm: error accepting connection from node: %d\n", result); return result; } /* Connect a new socket to its peer */ static void connect_to_sock(struct connection *con) { int result = -EHOSTUNREACH; struct sockaddr_storage saddr; int addr_len; struct socket *sock; if (con->nodeid == 0) { log_print("attempt to connect sock 0 foiled"); return; } down_write(&con->sock_sem); if (con->retries++ > MAX_CONNECT_RETRIES) goto out; /* Some odd races can cause double-connects, ignore them */ if (con->sock) { result = 0; goto out; } /* Create a socket to communicate with */ result = sock_create_kern(dlm_local_addr.ss_family, SOCK_STREAM, IPPROTO_TCP, &sock); if (result < 0) goto out_err; memset(&saddr, 0, sizeof(saddr)); if (dlm_nodeid_to_addr(con->nodeid, &saddr)) goto out_err; sock->sk->sk_user_data = con; con->rx_action = receive_from_sock; make_sockaddr(&saddr, dlm_config.tcp_port, &addr_len); add_sock(sock, con); log_print("connecting to %d", con->nodeid); result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len, O_NONBLOCK); if (result == -EINPROGRESS) result = 0; if (result == 0) goto out; out_err: if (con->sock) { sock_release(con->sock); con->sock = NULL; } /* * Some errors are fatal and this list might need adjusting. For other * errors we try again until the max number of retries is reached. */ if (result != -EHOSTUNREACH && result != -ENETUNREACH && result != -ENETDOWN && result != EINVAL && result != -EPROTONOSUPPORT) { lowcomms_connect_sock(con); result = 0; } out: up_write(&con->sock_sem); return; } static struct socket *create_listen_sock(struct connection *con, struct sockaddr_storage *saddr) { struct socket *sock = NULL; mm_segment_t fs; int result = 0; int one = 1; int addr_len; if (dlm_local_addr.ss_family == AF_INET) addr_len = sizeof(struct sockaddr_in); else addr_len = sizeof(struct sockaddr_in6); /* Create a socket to communicate with */ result = sock_create_kern(dlm_local_addr.ss_family, SOCK_STREAM, IPPROTO_TCP, &sock); if (result < 0) { printk("dlm: Can't create listening comms socket\n"); goto create_out; } fs = get_fs(); set_fs(get_ds()); result = sock_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&one, sizeof(one)); set_fs(fs); if (result < 0) { printk("dlm: Failed to set SO_REUSEADDR on socket: result=%d\n", result); } sock->sk->sk_user_data = con; con->rx_action = accept_from_sock; con->sock = sock; /* Bind to our port */ make_sockaddr(saddr, dlm_config.tcp_port, &addr_len); result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len); if (result < 0) { printk("dlm: Can't bind to port %d\n", dlm_config.tcp_port); sock_release(sock); sock = NULL; con->sock = NULL; goto create_out; } fs = get_fs(); set_fs(get_ds()); result = sock_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (char *)&one, sizeof(one)); set_fs(fs); if (result < 0) { printk("dlm: Set keepalive failed: %d\n", result); } result = sock->ops->listen(sock, 5); if (result < 0) { printk("dlm: Can't listen on port %d\n", dlm_config.tcp_port); sock_release(sock); sock = NULL; goto create_out; } create_out: return sock; } /* Listen on all interfaces */ static int listen_for_all(void) { struct socket *sock = NULL; struct connection *con = nodeid2con(0, GFP_KERNEL); int result = -EINVAL; /* We don't support multi-homed hosts */ set_bit(CF_IS_OTHERCON, &con->flags); sock = create_listen_sock(con, &dlm_local_addr); if (sock) { add_sock(sock, con); result = 0; } else { result = -EADDRINUSE; } return result; } static struct writequeue_entry *new_writequeue_entry(struct connection *con, gfp_t allocation) { struct writequeue_entry *entry; entry = kmalloc(sizeof(struct writequeue_entry), allocation); if (!entry) return NULL; entry->page = alloc_page(allocation); if (!entry->page) { kfree(entry); return NULL; } entry->offset = 0; entry->len = 0; entry->end = 0; entry->users = 0; entry->con = con; return entry; } void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc) { struct connection *con; struct writequeue_entry *e; int offset = 0; int users = 0; con = nodeid2con(nodeid, allocation); if (!con) return NULL; e = list_entry(con->writequeue.prev, struct writequeue_entry, list); if ((&e->list == &con->writequeue) || (PAGE_CACHE_SIZE - e->end < len)) { e = NULL; } else { offset = e->end; e->end += len; users = e->users++; } spin_unlock(&con->writequeue_lock); if (e) { got_one: if (users == 0) kmap(e->page); *ppc = page_address(e->page) + offset; return e; } e = new_writequeue_entry(con, allocation); if (e) { spin_lock(&con->writequeue_lock); offset = e->end; e->end += len; users = e->users++; list_add_tail(&e->list, &con->writequeue); spin_unlock(&con->writequeue_lock); goto got_one; } return NULL; } void dlm_lowcomms_commit_buffer(void *mh) { struct writequeue_entry *e = (struct writequeue_entry *)mh; struct connection *con = e->con; int users; users = --e->users; if (users) goto out; e->len = e->end - e->offset; kunmap(e->page); spin_unlock(&con->writequeue_lock); if (test_and_set_bit(CF_WRITE_PENDING, &con->flags) == 0) { spin_lock_bh(&write_sockets_lock); list_add_tail(&con->write_list, &write_sockets); spin_unlock_bh(&write_sockets_lock); wake_up_interruptible(&lowcomms_send_waitq); } return; out: spin_unlock(&con->writequeue_lock); return; } static void free_entry(struct writequeue_entry *e) { __free_page(e->page); kfree(e); } /* Send a message */ static void send_to_sock(struct connection *con) { int ret = 0; ssize_t(*sendpage) (struct socket *, struct page *, int, size_t, int); const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL; struct writequeue_entry *e; int len, offset; down_read(&con->sock_sem); if (con->sock == NULL) goto out_connect; sendpage = con->sock->ops->sendpage; spin_lock(&con->writequeue_lock); for (;;) { e = list_entry(con->writequeue.next, struct writequeue_entry, list); if ((struct list_head *) e == &con->writequeue) break; len = e->len; offset = e->offset; BUG_ON(len == 0 && e->users == 0); spin_unlock(&con->writequeue_lock); ret = 0; if (len) { ret = sendpage(con->sock, e->page, offset, len, msg_flags); if (ret == -EAGAIN || ret == 0) goto out; if (ret <= 0) goto send_error; } else { /* Don't starve people filling buffers */ cond_resched(); } spin_lock(&con->writequeue_lock); e->offset += ret; e->len -= ret; if (e->len == 0 && e->users == 0) { list_del(&e->list); kunmap(e->page); free_entry(e); continue; } } spin_unlock(&con->writequeue_lock); out: up_read(&con->sock_sem); return; send_error: up_read(&con->sock_sem); close_connection(con, false); lowcomms_connect_sock(con); return; out_connect: up_read(&con->sock_sem); lowcomms_connect_sock(con); return; } static void clean_one_writequeue(struct connection *con) { struct list_head *list; struct list_head *temp; spin_lock(&con->writequeue_lock); list_for_each_safe(list, temp, &con->writequeue) { struct writequeue_entry *e = list_entry(list, struct writequeue_entry, list); list_del(&e->list); free_entry(e); } spin_unlock(&con->writequeue_lock); } /* Called from recovery when it knows that a node has left the cluster */ int dlm_lowcomms_close(int nodeid) { struct connection *con; if (!connections) goto out; log_print("closing connection to node %d", nodeid); con = nodeid2con(nodeid, 0); if (con) { clean_one_writequeue(con); close_connection(con, true); atomic_set(&con->waiting_requests, 0); } return 0; out: return -1; } /* Look for activity on active sockets */ static void process_sockets(void) { struct list_head *list; struct list_head *temp; int count = 0; spin_lock_bh(&read_sockets_lock); list_for_each_safe(list, temp, &read_sockets) { struct connection *con = list_entry(list, struct connection, read_list); list_del(&con->read_list); clear_bit(CF_READ_PENDING, &con->flags); spin_unlock_bh(&read_sockets_lock); /* This can reach zero if we are processing requests * as they come in. */ if (atomic_read(&con->waiting_requests) == 0) { spin_lock_bh(&read_sockets_lock); continue; } do { con->rx_action(con); /* Don't starve out everyone else */ if (++count >= MAX_RX_MSG_COUNT) { cond_resched(); count = 0; } } while (!atomic_dec_and_test(&con->waiting_requests) && !kthread_should_stop()); spin_lock_bh(&read_sockets_lock); } spin_unlock_bh(&read_sockets_lock); } /* Try to send any messages that are pending */ static void process_output_queue(void) { struct list_head *list; struct list_head *temp; spin_lock_bh(&write_sockets_lock); list_for_each_safe(list, temp, &write_sockets) { struct connection *con = list_entry(list, struct connection, write_list); clear_bit(CF_WRITE_PENDING, &con->flags); list_del(&con->write_list); spin_unlock_bh(&write_sockets_lock); send_to_sock(con); spin_lock_bh(&write_sockets_lock); } spin_unlock_bh(&write_sockets_lock); } static void process_state_queue(void) { struct list_head *list; struct list_head *temp; spin_lock_bh(&state_sockets_lock); list_for_each_safe(list, temp, &state_sockets) { struct connection *con = list_entry(list, struct connection, state_list); list_del(&con->state_list); clear_bit(CF_CONNECT_PENDING, &con->flags); spin_unlock_bh(&state_sockets_lock); connect_to_sock(con); spin_lock_bh(&state_sockets_lock); } spin_unlock_bh(&state_sockets_lock); } /* Discard all entries on the write queues */ static void clean_writequeues(void) { int nodeid; for (nodeid = 1; nodeid < conn_array_size; nodeid++) { struct connection *con = nodeid2con(nodeid, 0); if (con) clean_one_writequeue(con); } } static int read_list_empty(void) { int status; spin_lock_bh(&read_sockets_lock); status = list_empty(&read_sockets); spin_unlock_bh(&read_sockets_lock); return status; } /* DLM Transport comms receive daemon */ static int dlm_recvd(void *data) { init_waitqueue_entry(&lowcomms_recv_waitq_head, current); add_wait_queue(&lowcomms_recv_waitq, &lowcomms_recv_waitq_head); while (!kthread_should_stop()) { set_current_state(TASK_INTERRUPTIBLE); if (read_list_empty()) schedule(); set_current_state(TASK_RUNNING); process_sockets(); } return 0; } static int write_and_state_lists_empty(void) { int status; spin_lock_bh(&write_sockets_lock); status = list_empty(&write_sockets); spin_unlock_bh(&write_sockets_lock); spin_lock_bh(&state_sockets_lock); if (list_empty(&state_sockets) == 0) status = 0; spin_unlock_bh(&state_sockets_lock); return status; } /* DLM Transport send daemon */ static int dlm_sendd(void *data) { init_waitqueue_entry(&lowcomms_send_waitq_head, current); add_wait_queue(&lowcomms_send_waitq, &lowcomms_send_waitq_head); while (!kthread_should_stop()) { set_current_state(TASK_INTERRUPTIBLE); if (write_and_state_lists_empty()) schedule(); set_current_state(TASK_RUNNING); process_state_queue(); process_output_queue(); } return 0; } static void daemons_stop(void) { kthread_stop(recv_task); kthread_stop(send_task); } static int daemons_start(void) { struct task_struct *p; int error; p = kthread_run(dlm_recvd, NULL, "dlm_recvd"); error = IS_ERR(p); if (error) { log_print("can't start dlm_recvd %d", error); return error; } recv_task = p; p = kthread_run(dlm_sendd, NULL, "dlm_sendd"); error = IS_ERR(p); if (error) { log_print("can't start dlm_sendd %d", error); kthread_stop(recv_task); return error; } send_task = p; return 0; } void dlm_lowcomms_stop(void) { int i; /* Set all the flags to prevent any socket activity. */ for (i = 0; i < conn_array_size; i++) { if (connections[i]) connections[i]->flags |= 0xFF; } daemons_stop(); clean_writequeues(); for (i = 0; i < conn_array_size; i++) { if (connections[i]) { close_connection(connections[i], true); if (connections[i]->othercon) kmem_cache_free(con_cache, connections[i]->othercon); kmem_cache_free(con_cache, connections[i]); } } kfree(connections); connections = NULL; kmem_cache_destroy(con_cache); } /* This is quite likely to sleep... */ int dlm_lowcomms_start(void) { int error = 0; error = -ENOMEM; connections = kzalloc(sizeof(struct connection *) * NODE_INCREMENT, GFP_KERNEL); if (!connections) goto out; conn_array_size = NODE_INCREMENT; if (dlm_our_addr(&dlm_local_addr, 0)) { log_print("no local IP address has been set"); goto fail_free_conn; } if (!dlm_our_addr(&dlm_local_addr, 1)) { log_print("This dlm comms module does not support multi-homed clustering"); goto fail_free_conn; } con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection), __alignof__(struct connection), 0, NULL, NULL); if (!con_cache) goto fail_free_conn; /* Start listening */ error = listen_for_all(); if (error) goto fail_unlisten; error = daemons_start(); if (error) goto fail_unlisten; return 0; fail_unlisten: close_connection(connections[0], false); kmem_cache_free(con_cache, connections[0]); kmem_cache_destroy(con_cache); fail_free_conn: kfree(connections); out: return error; } /* * Overrides for Emacs so that we follow Linus's tabbing style. * Emacs will notice this stuff at the end of the file and automatically * adjust the settings for this buffer only. This must remain at the end * of the file. * --------------------------------------------------------------------------- * Local variables: * c-file-style: "linux" * End: */