diff options
Diffstat (limited to 'kernel/net/rds/loop.c')
| -rw-r--r-- | kernel/net/rds/loop.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/kernel/net/rds/loop.c b/kernel/net/rds/loop.c new file mode 100644 index 000000000..6b12b6854 --- /dev/null +++ b/kernel/net/rds/loop.c @@ -0,0 +1,194 @@ +/* + * Copyright (c) 2006 Oracle. All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + * + */ +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/in.h> + +#include "rds.h" +#include "loop.h" + +static DEFINE_SPINLOCK(loop_conns_lock); +static LIST_HEAD(loop_conns); + +/* + * This 'loopback' transport is a special case for flows that originate + * and terminate on the same machine. + * + * Connection build-up notices if the destination address is thought of + * as a local address by a transport. At that time it decides to use the + * loopback transport instead of the bound transport of the sending socket. + * + * The loopback transport's sending path just hands the sent rds_message + * straight to the receiving path via an embedded rds_incoming. + */ + +/* + * Usually a message transits both the sender and receiver's conns as it + * flows to the receiver. In the loopback case, though, the receive path + * is handed the sending conn so the sense of the addresses is reversed. + */ +static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, + unsigned int hdr_off, unsigned int sg, + unsigned int off) +{ + struct scatterlist *sgp = &rm->data.op_sg[sg]; + int ret = sizeof(struct rds_header) + + be32_to_cpu(rm->m_inc.i_hdr.h_len); + + /* Do not send cong updates to loopback */ + if (rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { + rds_cong_map_updated(conn->c_fcong, ~(u64) 0); + ret = min_t(int, ret, sgp->length - conn->c_xmit_data_off); + goto out; + } + + BUG_ON(hdr_off || sg || off); + + rds_inc_init(&rm->m_inc, conn, conn->c_laddr); + /* For the embedded inc. Matching put is in loop_inc_free() */ + rds_message_addref(rm); + + rds_recv_incoming(conn, conn->c_laddr, conn->c_faddr, &rm->m_inc, + GFP_KERNEL); + + rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence), + NULL); + + rds_inc_put(&rm->m_inc); +out: + return ret; +} + +/* + * See rds_loop_xmit(). Since our inc is embedded in the rm, we + * make sure the rm lives at least until the inc is done. + */ +static void rds_loop_inc_free(struct rds_incoming *inc) +{ + struct rds_message *rm = container_of(inc, struct rds_message, m_inc); + rds_message_put(rm); +} + +/* we need to at least give the thread something to succeed */ +static int rds_loop_recv(struct rds_connection *conn) +{ + return 0; +} + +struct rds_loop_connection { + struct list_head loop_node; + struct rds_connection *conn; +}; + +/* + * Even the loopback transport needs to keep track of its connections, + * so it can call rds_conn_destroy() on them on exit. N.B. there are + * 1+ loopback addresses (127.*.*.*) so it's not a bug to have + * multiple loopback conns allocated, although rather useless. + */ +static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp) +{ + struct rds_loop_connection *lc; + unsigned long flags; + + lc = kzalloc(sizeof(struct rds_loop_connection), gfp); + if (!lc) + return -ENOMEM; + + INIT_LIST_HEAD(&lc->loop_node); + lc->conn = conn; + conn->c_transport_data = lc; + + spin_lock_irqsave(&loop_conns_lock, flags); + list_add_tail(&lc->loop_node, &loop_conns); + spin_unlock_irqrestore(&loop_conns_lock, flags); + + return 0; +} + +static void rds_loop_conn_free(void *arg) +{ + struct rds_loop_connection *lc = arg; + unsigned long flags; + + rdsdebug("lc %p\n", lc); + spin_lock_irqsave(&loop_conns_lock, flags); + list_del(&lc->loop_node); + spin_unlock_irqrestore(&loop_conns_lock, flags); + kfree(lc); +} + +static int rds_loop_conn_connect(struct rds_connection *conn) +{ + rds_connect_complete(conn); + return 0; +} + +static void rds_loop_conn_shutdown(struct rds_connection *conn) +{ +} + +void rds_loop_exit(void) +{ + struct rds_loop_connection *lc, *_lc; + LIST_HEAD(tmp_list); + + /* avoid calling conn_destroy with irqs off */ + spin_lock_irq(&loop_conns_lock); + list_splice(&loop_conns, &tmp_list); + INIT_LIST_HEAD(&loop_conns); + spin_unlock_irq(&loop_conns_lock); + + list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { + WARN_ON(lc->conn->c_passive); + rds_conn_destroy(lc->conn); + } +} + +/* + * This is missing .xmit_* because loop doesn't go through generic + * rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and + * .laddr_check are missing because transport.c doesn't iterate over + * rds_loop_transport. + */ +struct rds_transport rds_loop_transport = { + .xmit = rds_loop_xmit, + .recv = rds_loop_recv, + .conn_alloc = rds_loop_conn_alloc, + .conn_free = rds_loop_conn_free, + .conn_connect = rds_loop_conn_connect, + .conn_shutdown = rds_loop_conn_shutdown, + .inc_copy_to_user = rds_message_inc_copy_to_user, + .inc_free = rds_loop_inc_free, + .t_name = "loopback", +}; |