--- /dev/null
+/******************************************************************************
+*******************************************************************************
+**
+** 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 base;
+ unsigned len;
+ unsigned mask;
+};
+
+#ifndef FALSE
+#define FALSE 0
+#define TRUE 1
+#endif
+#define NODE_INCREMENT 32
+
+#define CBUF_INIT(cb, size) do { (cb)->base = (cb)->len = 0; (cb)->mask = ((size)-1); } while(0)
+#define CBUF_ADD(cb, n) do { (cb)->len += n; } while(0)
+#define CBUF_EMPTY(cb) ((cb)->len == 0)
+#define CBUF_MAY_ADD(cb, n) (((cb)->len + (n)) < ((cb)->mask + 1))
+#define CBUF_EAT(cb, n) do { (cb)->len -= (n); \
+ (cb)->base += (n); (cb)->base &= (cb)->mask; } while(0)
+#define CBUF_DATA(cb) (((cb)->base + (cb)->len) & (cb)->mask)
+
+/* Maximum number of incoming messages to process before
+ doing a schedule()
+*/
+#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 wait_queue_head_t lowcomms_send_waitq;
+static wait_queue_t lowcomms_recv_waitq_head;
+static wait_queue_head_t lowcomms_recv_waitq;
+
+/* An array of pointers to connections, indexed by NODEID */
+static struct connection **connections;
+static struct semaphore connections_lock;
+static kmem_cache_t *con_cache;
+static int conn_array_size;
+static atomic_t accepting;
+
+/* List of sockets that have reads pending */
+static struct list_head read_sockets;
+static spinlock_t read_sockets_lock;
+
+/* List of sockets which have writes pending */
+static struct list_head write_sockets;
+static spinlock_t write_sockets_lock;
+
+/* List of sockets which have connects pending */
+static struct list_head state_sockets;
+static spinlock_t 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 = kmalloc(sizeof(struct connection *) *
+ new_size, allocation);
+ if (!new_conns)
+ goto finish;
+
+ memset(new_conns, 0, sizeof(struct connection *) * new_size);
+ 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_alloc(con_cache, allocation);
+ if (!con)
+ goto finish;
+
+ memset(con, 0, sizeof(*con));
+ 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;
+ if (!atomic_read(&accepting))
+ 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)
+{
+/* struct connection *con = sock2con(sk); */
+
+ switch (sk->sk_state) {
+ case TCP_ESTABLISHED:
+ lowcomms_write_space(sk);
+ break;
+
+ case TCP_FIN_WAIT1:
+ case TCP_FIN_WAIT2:
+ case TCP_TIME_WAIT:
+ case TCP_CLOSE:
+ case TCP_CLOSE_WAIT:
+ case TCP_LAST_ACK:
+ case TCP_CLOSING:
+ /* FIXME: I think this causes more trouble than it solves.
+ lowcomms wil reconnect anyway when there is something to
+ send. This just attempts reconnection if a node goes down!
+ */
+ /* lowcomms_connect_sock(con); */
+ break;
+
+ default:
+ printk("dlm: lowcomms_state_change: state=%d\n", sk->sk_state);
+ break;
+ }
+}
+
+/* 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, int and_other)
+{
+ down_write(&con->sock_sem);
+
+ if (con->sock) {
+ sock_release(con->sock);
+ con->sock = NULL;
+ }
+ if (con->othercon && and_other) {
+ /* Argh! recursion in kernel code!
+ Actually, this isn't a list so it
+ 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);
+ ret = 0;
+ goto out_ret;
+
+ out_resched:
+ lowcomms_data_ready(con->sock->sk, 0);
+ up_read(&con->sock_sem);
+ ret = 0;
+ schedule();
+ goto out_ret;
+
+ 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 */
+ }
+
+ out_ret:
+ 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_alloc(con_cache, GFP_KERNEL);
+ if (!othercon) {
+ printk("dlm: failed to allocate incoming socket\n");
+ up_write(&newcon->sock_sem);
+ result = -ENOMEM;
+ goto accept_err;
+ }
+ memset(othercon, 0, sizeof(*othercon));
+ 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 int 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 0;
+ }
+
+ 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_err;
+
+ out:
+ up_write(&con->sock_sem);
+ /*
+ * Returning an error here means we've given up trying to connect to
+ * a remote node, otherwise we return 0 and reschedule the connetion
+ * attempt
+ */
+ return result;
+
+ 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;
+ }
+ goto out;
+}
+
+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 */
+ memset(con, 0, sizeof(*con));
+ init_rwsem(&con->sock_sem);
+ spin_lock_init(&con->writequeue_lock);
+ INIT_LIST_HEAD(&con->writequeue);
+ 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;
+
+ if (!atomic_read(&accepting))
+ return NULL;
+
+ con = nodeid2con(nodeid, allocation);
+ if (!con)
+ return NULL;
+
+ spin_lock(&con->writequeue_lock);
+ e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
+ if (((struct list_head *) e == &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;
+
+ if (!atomic_read(&accepting))
+ return;
+
+ spin_lock(&con->writequeue_lock);
+ 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 int 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 */
+ schedule();
+ }
+
+ spin_lock(&con->writequeue_lock);
+ e->offset += ret;
+ e->len -= ret;
+
+ if (e->len == 0 && e->users == 0) {
+ list_del(&e->list);
+ free_entry(e);
+ continue;
+ }
+ }
+ spin_unlock(&con->writequeue_lock);
+ out:
+ up_read(&con->sock_sem);
+ return ret;
+
+ send_error:
+ up_read(&con->sock_sem);
+ close_connection(con, FALSE);
+ lowcomms_connect_sock(con);
+ return ret;
+
+ out_connect:
+ up_read(&con->sock_sem);
+ lowcomms_connect_sock(con);
+ return 0;
+}
+
+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) {
+ schedule();
+ 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;
+ int ret;
+
+ 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);
+
+ ret = send_to_sock(con);
+ if (ret < 0) {
+ }
+ 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;
+ int ret;
+
+ 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);
+
+ ret = connect_to_sock(con);
+ if (ret < 0) {
+ }
+ 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_head(&lowcomms_recv_waitq);
+ 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_head(&lowcomms_send_waitq);
+ 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;
+}
+
+/*
+ * 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;
+
+ atomic_set(&accepting, 0);
+
+ /* Set all the activity flags to prevent any
+ socket activity.
+ */
+ for (i = 0; i < conn_array_size; i++) {
+ if (connections[i])
+ connections[i]->flags |= 0x7;
+ }
+ 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 = -ENOTCONN;
+
+ /*
+ * Temporarily initialise the waitq head so that lowcomms_send_message
+ * doesn't crash if it gets called before the thread is fully
+ * initialised
+ */
+ init_waitqueue_head(&lowcomms_send_waitq);
+
+ error = -ENOMEM;
+ connections = kmalloc(sizeof(struct connection *) *
+ NODE_INCREMENT, GFP_KERNEL);
+ if (!connections)
+ goto out;
+
+ memset(connections, 0,
+ sizeof(struct connection *) * NODE_INCREMENT);
+
+ 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;
+
+ atomic_set(&accepting, 1);
+
+ return 0;
+
+ fail_unlisten:
+ close_connection(connections[0], 0);
+ kmem_cache_free(con_cache, connections[0]);
+ kmem_cache_destroy(con_cache);
+
+ fail_free_conn:
+ kfree(connections);
+
+ out:
+ return error;
+}
+
+int dlm_lowcomms_init(void)
+{
+ INIT_LIST_HEAD(&read_sockets);
+ INIT_LIST_HEAD(&write_sockets);
+ INIT_LIST_HEAD(&state_sockets);
+
+ spin_lock_init(&read_sockets_lock);
+ spin_lock_init(&write_sockets_lock);
+ spin_lock_init(&state_sockets_lock);
+ init_MUTEX(&connections_lock);
+
+ return 0;
+}
+
+void dlm_lowcomms_exit(void)
+{
+}
+
+/*
+ * 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:
+ */
projects / linux-2.6-omap-h63xx.git / commitdiff