diff options
Diffstat (limited to 'fs/dlm/lowcomms-tcp.c')
| -rw-r--r-- | fs/dlm/lowcomms-tcp.c | 1189 |
1 files changed, 1189 insertions, 0 deletions
diff --git a/fs/dlm/lowcomms-tcp.c b/fs/dlm/lowcomms-tcp.c new file mode 100644 index 000000000000..9be3a440c42a --- /dev/null +++ b/fs/dlm/lowcomms-tcp.c @@ -0,0 +1,1189 @@ +/****************************************************************************** +******************************************************************************* +** +** 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 <asm/ioctls.h> +#include <net/sock.h> +#include <net/tcp.h> +#include <linux/pagemap.h> + +#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; +} + +/* API send message call, may queue the request */ +/* N.B. This is the old interface - use the new one for new calls */ +int lowcomms_send_message(int nodeid, char *buf, int len, gfp_t allocation) +{ + struct writequeue_entry *e; + char *b; + + e = dlm_lowcomms_get_buffer(nodeid, len, allocation, &b); + if (e) { + memcpy(b, buf, len); + dlm_lowcomms_commit_buffer(e); + return 0; + } + return -ENOBUFS; +} + +/* 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()) + cond_resched(); + 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()) + cond_resched(); + 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; +} + +/* + * Return the largest buffer size we can cope with. + */ +int lowcomms_max_buffer_size(void) +{ + return PAGE_CACHE_SIZE; +} + +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: + */ |