From a2376185dcad0040601768041c2a7e68edc9f4b8 Mon Sep 17 00:00:00 2001 From: Evgeniy Polyakov Date: Wed, 14 Jan 2009 02:05:28 +0300 Subject: [PATCH] Staging: dst: network state machine. Each DST device contains of two nodes: local and remote (called also as export node). This patch contains local node processing engine: network state storage, socket processing loops and state machine, socket polling machinery, reconnection logic, send/receive basic helpers, related IO commands and so on. Signed-off-by: Evgeniy Polyakov Signed-off-by: Greg Kroah-Hartman --- drivers/staging/dst/state.c | 839 ++++++++++++++++++++++++++++++++++++ 1 file changed, 839 insertions(+) create mode 100644 drivers/staging/dst/state.c diff --git a/drivers/staging/dst/state.c b/drivers/staging/dst/state.c new file mode 100644 index 000000000000..d057e52f3b64 --- /dev/null +++ b/drivers/staging/dst/state.c @@ -0,0 +1,839 @@ +/* + * 2007+ Copyright (c) Evgeniy Polyakov + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +/* + * Polling machinery. + */ + +struct dst_poll_helper +{ + poll_table pt; + struct dst_state *st; +}; + +static int dst_queue_wake(wait_queue_t *wait, unsigned mode, int sync, void *key) +{ + struct dst_state *st = container_of(wait, struct dst_state, wait); + + wake_up(&st->thread_wait); + return 1; +} + +static void dst_queue_func(struct file *file, wait_queue_head_t *whead, + poll_table *pt) +{ + struct dst_state *st = container_of(pt, struct dst_poll_helper, pt)->st; + + st->whead = whead; + init_waitqueue_func_entry(&st->wait, dst_queue_wake); + add_wait_queue(whead, &st->wait); +} + +void dst_poll_exit(struct dst_state *st) +{ + if (st->whead) { + remove_wait_queue(st->whead, &st->wait); + st->whead = NULL; + } +} + +int dst_poll_init(struct dst_state *st) +{ + struct dst_poll_helper ph; + + ph.st = st; + init_poll_funcptr(&ph.pt, &dst_queue_func); + + st->socket->ops->poll(NULL, st->socket, &ph.pt); + return 0; +} + +/* + * Header receiving function - may block. + */ +static int dst_data_recv_header(struct socket *sock, + void *data, unsigned int size, int block) +{ + struct msghdr msg; + struct kvec iov; + int err; + + iov.iov_base = data; + iov.iov_len = size; + + msg.msg_iov = (struct iovec *)&iov; + msg.msg_iovlen = 1; + msg.msg_name = NULL; + msg.msg_namelen = 0; + msg.msg_control = NULL; + msg.msg_controllen = 0; + msg.msg_flags = (block)?MSG_WAITALL:MSG_DONTWAIT; + + err = kernel_recvmsg(sock, &msg, &iov, 1, iov.iov_len, + msg.msg_flags); + if (err != size) + return -1; + + return 0; +} + +/* + * Header sending function - may block. + */ +int dst_data_send_header(struct socket *sock, + void *data, unsigned int size, int more) +{ + struct msghdr msg; + struct kvec iov; + int err; + + iov.iov_base = data; + iov.iov_len = size; + + msg.msg_iov = (struct iovec *)&iov; + msg.msg_iovlen = 1; + msg.msg_name = NULL; + msg.msg_namelen = 0; + msg.msg_control = NULL; + msg.msg_controllen = 0; + msg.msg_flags = MSG_WAITALL | (more)?MSG_MORE:0; + + err = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len); + if (err != size) { + dprintk("%s: size: %u, more: %d, err: %d.\n", + __func__, size, more, err); + return -1; + } + + return 0; +} + +/* + * Block autoconfiguration: request size of the storage and permissions. + */ +static int dst_request_remote_config(struct dst_state *st) +{ + struct dst_node *n = st->node; + int err = -EINVAL; + struct dst_cmd *cmd = st->data; + + memset(cmd, 0, sizeof(struct dst_cmd)); + cmd->cmd = DST_CFG; + + dst_convert_cmd(cmd); + + err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0); + if (err) + goto out; + + err = dst_data_recv_header(st->socket, cmd, sizeof(struct dst_cmd), 1); + if (err) + goto out; + + dst_convert_cmd(cmd); + + if (cmd->cmd != DST_CFG) { + err = -EINVAL; + dprintk("%s: checking result: cmd: %d, size reported: %llu.\n", + __func__, cmd->cmd, cmd->sector); + goto out; + } + + if (n->size != 0) + n->size = min_t(loff_t, n->size, cmd->sector); + else + n->size = cmd->sector; + + n->info->size = n->size; + st->permissions = cmd->rw; + +out: + dprintk("%s: n: %p, err: %d, size: %llu, permission: %x.\n", + __func__, n, err, n->size, st->permissions); + return err; +} + +/* + * Socket machinery. + */ + +#define DST_DEFAULT_TIMEO 20000 + +int dst_state_socket_create(struct dst_state *st) +{ + int err; + struct socket *sock; + struct dst_network_ctl *ctl = &st->ctl; + + err = sock_create(ctl->addr.sa_family, ctl->type, ctl->proto, &sock); + if (err < 0) + return err; + + sock->sk->sk_sndtimeo = sock->sk->sk_rcvtimeo = + msecs_to_jiffies(DST_DEFAULT_TIMEO); + sock->sk->sk_allocation = GFP_NOIO; + + st->socket = st->read_socket = sock; + return 0; +} + +void dst_state_socket_release(struct dst_state *st) +{ + dprintk("%s: st: %p, socket: %p, n: %p.\n", + __func__, st, st->socket, st->node); + if (st->socket) { + sock_release(st->socket); + st->socket = NULL; + st->read_socket = NULL; + } +} + +void dst_dump_addr(struct socket *sk, struct sockaddr *sa, char *str) +{ + if (sk->ops->family == AF_INET) { + struct sockaddr_in *sin = (struct sockaddr_in *)sa; + printk(KERN_INFO "%s %u.%u.%u.%u:%d.\n", + str, NIPQUAD(sin->sin_addr.s_addr), ntohs(sin->sin_port)); + } else if (sk->ops->family == AF_INET6) { + struct sockaddr_in6 *sin = (struct sockaddr_in6 *)sa; + printk(KERN_INFO "%s %pi6:%d", + str, &sin->sin6_addr, ntohs(sin->sin6_port)); + } +} + +void dst_state_exit_connected(struct dst_state *st) +{ + if (st->socket) { + dst_poll_exit(st); + st->socket->ops->shutdown(st->socket, 2); + + dst_dump_addr(st->socket, (struct sockaddr *)&st->ctl.addr, + "Disconnected peer"); + dst_state_socket_release(st); + } +} + +static int dst_state_init_connected(struct dst_state *st) +{ + int err; + struct dst_network_ctl *ctl = &st->ctl; + + err = dst_state_socket_create(st); + if (err) + goto err_out_exit; + + err = kernel_connect(st->socket, (struct sockaddr *)&st->ctl.addr, + st->ctl.addr.sa_data_len, 0); + if (err) + goto err_out_release; + + err = dst_poll_init(st); + if (err) + goto err_out_release; + + dst_dump_addr(st->socket, (struct sockaddr *)&ctl->addr, + "Connected to peer"); + + return 0; + +err_out_release: + dst_state_socket_release(st); +err_out_exit: + return err; +} + +/* + * State reset is used to reconnect to the remote peer. + * May fail, but who cares, we will try again later. + */ +static void inline dst_state_reset_nolock(struct dst_state *st) +{ + dst_state_exit_connected(st); + dst_state_init_connected(st); +} + +static void inline dst_state_reset(struct dst_state *st) +{ + dst_state_lock(st); + dst_state_reset_nolock(st); + dst_state_unlock(st); +} + +/* + * Basic network sending/receiving functions. + * Blocked mode is used. + */ +static int dst_data_recv_raw(struct dst_state *st, void *buf, u64 size) +{ + struct msghdr msg; + struct kvec iov; + int err; + + BUG_ON(!size); + + iov.iov_base = buf; + iov.iov_len = size; + + msg.msg_iov = (struct iovec *)&iov; + msg.msg_iovlen = 1; + msg.msg_name = NULL; + msg.msg_namelen = 0; + msg.msg_control = NULL; + msg.msg_controllen = 0; + msg.msg_flags = MSG_DONTWAIT; + + err = kernel_recvmsg(st->socket, &msg, &iov, 1, iov.iov_len, + msg.msg_flags); + if (err <= 0) { + dprintk("%s: failed to recv data: size: %llu, err: %d.\n", + __func__, size, err); + if (err == 0) + err = -ECONNRESET; + + dst_state_exit_connected(st); + } + + return err; +} + +/* + * Ping command to early detect failed nodes. + */ +static int dst_send_ping(struct dst_state *st) +{ + struct dst_cmd *cmd = st->data; + int err = -ECONNRESET; + + dst_state_lock(st); + if (st->socket) { + memset(cmd, 0, sizeof(struct dst_cmd)); + + cmd->cmd = __cpu_to_be32(DST_PING); + + err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0); + } + dprintk("%s: st: %p, socket: %p, err: %d.\n", __func__, st, st->socket, err); + dst_state_unlock(st); + + return err; +} + +/* + * Receiving function, which should either return error or read + * whole block request. If there was no traffic for a one second, + * send a ping, since remote node may die. + */ +int dst_data_recv(struct dst_state *st, void *data, unsigned int size) +{ + unsigned int revents = 0; + unsigned int err_mask = POLLERR | POLLHUP | POLLRDHUP; + unsigned int mask = err_mask | POLLIN; + struct dst_node *n = st->node; + int err = 0; + + while (size && !err) { + revents = dst_state_poll(st); + + if (!(revents & mask)) { + DEFINE_WAIT(wait); + + for (;;) { + prepare_to_wait(&st->thread_wait, &wait, + TASK_INTERRUPTIBLE); + if (!n->trans_scan_timeout || st->need_exit) + break; + + revents = dst_state_poll(st); + + if (revents & mask) + break; + + if (signal_pending(current)) + break; + + if (!schedule_timeout(HZ)) { + err = dst_send_ping(st); + if (err) + return err; + } + + continue; + } + finish_wait(&st->thread_wait, &wait); + } + + err = -ECONNRESET; + dst_state_lock(st); + + if ( st->socket && + (st->read_socket == st->socket) && + (revents & POLLIN)) { + err = dst_data_recv_raw(st, data, size); + if (err > 0) { + data += err; + size -= err; + err = 0; + } + } + + if (revents & err_mask || !st->socket) { + dprintk("%s: revents: %x, socket: %p, size: %u, err: %d.\n", + __func__, revents, st->socket, size, err); + err = -ECONNRESET; + } + + dst_state_unlock(st); + + if (!n->trans_scan_timeout) + err = -ENODEV; + } + + return err; +} + +/* + * Send block autoconf reply. + */ +static int dst_process_cfg(struct dst_state *st) +{ + struct dst_node *n = st->node; + struct dst_cmd *cmd = st->data; + int err; + + cmd->sector = n->size; + cmd->rw = st->permissions; + + dst_convert_cmd(cmd); + + dst_state_lock(st); + err = dst_data_send_header(st->socket, cmd, sizeof(struct dst_cmd), 0); + dst_state_unlock(st); + + return err; +} + +/* + * Receive block IO from the network. + */ +static int dst_recv_bio(struct dst_state *st, struct bio *bio, unsigned int total_size) +{ + struct bio_vec *bv; + int i, err; + void *data; + unsigned int sz; + + bio_for_each_segment(bv, bio, i) { + sz = min(total_size, bv->bv_len); + + dprintk("%s: bio: %llu/%u, total: %u, len: %u, sz: %u, off: %u.\n", + __func__, (u64)bio->bi_sector, bio->bi_size, total_size, + bv->bv_len, sz, bv->bv_offset); + + data = kmap(bv->bv_page) + bv->bv_offset; + err = dst_data_recv(st, data, sz); + kunmap(bv->bv_page); + + bv->bv_len = sz; + + if (err) + return err; + + total_size -= sz; + if (total_size == 0) + break; + } + + return 0; +} + +/* + * Our block IO has just completed and arrived: get it. + */ +static int dst_process_io_response(struct dst_state *st) +{ + struct dst_node *n = st->node; + struct dst_cmd *cmd = st->data; + struct dst_trans *t; + int err = 0; + struct bio *bio; + + mutex_lock(&n->trans_lock); + t = dst_trans_search(n, cmd->id); + mutex_unlock(&n->trans_lock); + + if (!t) + goto err_out_exit; + + bio = t->bio; + + dprintk("%s: bio: %llu/%u, cmd_size: %u, csize: %u, dir: %lu.\n", + __func__, (u64)bio->bi_sector, bio->bi_size, cmd->size, + cmd->csize, bio_data_dir(bio)); + + if (bio_data_dir(bio) == READ) { + if (bio->bi_size != cmd->size - cmd->csize) + goto err_out_exit; + + if (dst_need_crypto(n)) { + err = dst_recv_cdata(st, t->cmd.hash); + if (err) + goto err_out_exit; + } + + err = dst_recv_bio(st, t->bio, bio->bi_size); + if (err) + goto err_out_exit; + + if (dst_need_crypto(n)) + return dst_trans_crypto(t); + } else { + err = -EBADMSG; + if (cmd->size || cmd->csize) + goto err_out_exit; + } + + dst_trans_remove(t); + dst_trans_put(t); + + return 0; + +err_out_exit: + return err; +} + +/* + * Receive crypto data. + */ +int dst_recv_cdata(struct dst_state *st, void *cdata) +{ + struct dst_cmd *cmd = st->data; + struct dst_node *n = st->node; + struct dst_crypto_ctl *c = &n->crypto; + int err; + + if (cmd->csize != c->crypto_attached_size) { + dprintk("%s: cmd: cmd: %u, sector: %llu, size: %u, " + "csize: %u != digest size %u.\n", + __func__, cmd->cmd, cmd->sector, cmd->size, + cmd->csize, c->crypto_attached_size); + err = -EINVAL; + goto err_out_exit; + } + + err = dst_data_recv(st, cdata, cmd->csize); + if (err) + goto err_out_exit; + + cmd->size -= cmd->csize; + return 0; + +err_out_exit: + return err; +} + +/* + * Receive the command and start its processing. + */ +static int dst_recv_processing(struct dst_state *st) +{ + int err = -EINTR; + struct dst_cmd *cmd = st->data; + + /* + * If socket will be reset after this statement, then + * dst_data_recv() will just fail and loop will + * start again, so it can be done without any locks. + * + * st->read_socket is needed to prevents state machine + * breaking between this data reading and subsequent one + * in protocol specific functions during connection reset. + * In case of reset we have to read next command and do + * not expect data for old command to magically appear in + * new connection. + */ + st->read_socket = st->socket; + err = dst_data_recv(st, cmd, sizeof(struct dst_cmd)); + if (err) + goto out_exit; + + dst_convert_cmd(cmd); + + dprintk("%s: cmd: %u, size: %u, csize: %u, id: %llu, " + "sector: %llu, flags: %llx, rw: %llx.\n", + __func__, cmd->cmd, cmd->size, + cmd->csize, cmd->id, cmd->sector, + cmd->flags, cmd->rw); + + /* + * This should catch protocol breakage and random garbage instead of commands. + */ + if (unlikely(cmd->csize > st->size - sizeof(struct dst_cmd))) { + err = -EBADMSG; + goto out_exit; + } + + err = -EPROTO; + switch (cmd->cmd) { + case DST_IO_RESPONSE: + err = dst_process_io_response(st); + break; + case DST_IO: + err = dst_process_io(st); + break; + case DST_CFG: + err = dst_process_cfg(st); + break; + case DST_PING: + err = 0; + break; + default: + break; + } + +out_exit: + return err; +} + +/* + * Receiving thread. For the client node we should try to reconnect, + * for accepted client we just drop the state and expect it to reconnect. + */ +static int dst_recv(void *init_data, void *schedule_data) +{ + struct dst_state *st = schedule_data; + struct dst_node *n = init_data; + int err = 0; + + dprintk("%s: start st: %p, n: %p, scan: %lu, need_exit: %d.\n", + __func__, st, n, n->trans_scan_timeout, st->need_exit); + + while (n->trans_scan_timeout && !st->need_exit) { + err = dst_recv_processing(st); + if (err < 0) { + if (!st->ctl.type) + break; + + if (!n->trans_scan_timeout || st->need_exit) + break; + + dst_state_reset(st); + msleep(1000); + } + } + + st->need_exit = 1; + wake_up(&st->thread_wait); + + dprintk("%s: freeing receiving socket st: %p.\n", __func__, st); + dst_state_lock(st); + dst_state_exit_connected(st); + dst_state_unlock(st); + dst_state_put(st); + + dprintk("%s: freed receiving socket st: %p.\n", __func__, st); + + return err; +} + +/* + * Network state dies here and borns couple of lines below. + * This object is the main network state processing engine: + * sending, receiving, reconnections, all network related + * tasks are handled on behalf of the state. + */ +static void dst_state_free(struct dst_state *st) +{ + dprintk("%s: st: %p.\n", __func__, st); + if (st->cleanup) + st->cleanup(st); + kfree(st->data); + kfree(st); +} + +struct dst_state *dst_state_alloc(struct dst_node *n) +{ + struct dst_state *st; + int err = -ENOMEM; + + st = kzalloc(sizeof(struct dst_state), GFP_KERNEL); + if (!st) + goto err_out_exit; + + st->node = n; + st->need_exit = 0; + + st->size = PAGE_SIZE; + st->data = kmalloc(st->size, GFP_KERNEL); + if (!st->data) + goto err_out_free; + + spin_lock_init(&st->request_lock); + INIT_LIST_HEAD(&st->request_list); + + mutex_init(&st->state_lock); + init_waitqueue_head(&st->thread_wait); + + /* + * One for processing thread, another one for node itself. + */ + atomic_set(&st->refcnt, 2); + + dprintk("%s: st: %p, n: %p.\n", __func__, st, st->node); + + return st; + +err_out_free: + kfree(st); +err_out_exit: + return ERR_PTR(err); +} + +int dst_state_schedule_receiver(struct dst_state *st) +{ + return thread_pool_schedule_private(st->node->pool, dst_thread_setup, + dst_recv, st, MAX_SCHEDULE_TIMEOUT, st->node); +} + +/* + * Initialize client's connection to the remote peer: allocate state, + * connect and perform block IO autoconfiguration. + */ +int dst_node_init_connected(struct dst_node *n, struct dst_network_ctl *r) +{ + struct dst_state *st; + int err = -ENOMEM; + + st = dst_state_alloc(n); + if (IS_ERR(st)) { + err = PTR_ERR(st); + goto err_out_exit; + } + memcpy(&st->ctl, r, sizeof(struct dst_network_ctl)); + + err = dst_state_init_connected(st); + if (err) + goto err_out_free_data; + + err = dst_request_remote_config(st); + if (err) + goto err_out_exit_connected; + n->state = st; + + err = dst_state_schedule_receiver(st); + if (err) + goto err_out_exit_connected; + + return 0; + +err_out_exit_connected: + dst_state_exit_connected(st); +err_out_free_data: + dst_state_free(st); +err_out_exit: + n->state = NULL; + return err; +} + +void dst_state_put(struct dst_state *st) +{ + dprintk("%s: st: %p, refcnt: %d.\n", + __func__, st, atomic_read(&st->refcnt)); + if (atomic_dec_and_test(&st->refcnt)) + dst_state_free(st); +} + +/* + * Send block IO to the network one by one using zero-copy ->sendpage(). + */ +int dst_send_bio(struct dst_state *st, struct dst_cmd *cmd, struct bio *bio) +{ + struct bio_vec *bv; + struct dst_crypto_ctl *c = &st->node->crypto; + int err, i = 0; + int flags = MSG_WAITALL; + + err = dst_data_send_header(st->socket, cmd, + sizeof(struct dst_cmd) + c->crypto_attached_size, bio->bi_vcnt); + if (err) + goto err_out_exit; + + bio_for_each_segment(bv, bio, i) { + if (i < bio->bi_vcnt - 1) + flags |= MSG_MORE; + + err = kernel_sendpage(st->socket, bv->bv_page, bv->bv_offset, + bv->bv_len, flags); + if (err <= 0) + goto err_out_exit; + } + + return 0; + +err_out_exit: + dprintk("%s: %d/%d, flags: %x, err: %d.\n", + __func__, i, bio->bi_vcnt, flags, err); + return err; +} + +/* + * Send transaction to the remote peer. + */ +int dst_trans_send(struct dst_trans *t) +{ + int err; + struct dst_state *st = t->n->state; + struct bio *bio = t->bio; + + dst_convert_cmd(&t->cmd); + + dst_state_lock(st); + if (!st->socket) { + err = dst_state_init_connected(st); + if (err) + goto err_out_unlock; + } + + if (bio_data_dir(bio) == WRITE) { + err = dst_send_bio(st, &t->cmd, t->bio); + } else { + err = dst_data_send_header(st->socket, &t->cmd, + sizeof(struct dst_cmd), 0); + } + if (err) + goto err_out_reset; + + dst_state_unlock(st); + return 0; + +err_out_reset: + dst_state_reset_nolock(st); +err_out_unlock: + dst_state_unlock(st); + + return err; +} -- 2.20.1