cregit-Linux how code gets into the kernel

Release 4.11 net/rds/loop.c

Directory: net/rds
/*
 * 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_single_path.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; }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover13570.68%375.00%
Neil Horman5629.32%125.00%
Total191100.00%4100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover31100.00%1100.00%
Total31100.00%1100.00%

/* we need to at least give the thread something to succeed */
static int rds_loop_recv_path(struct rds_conn_path *cp) { return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover1178.57%150.00%
Sowmini Varadhan321.43%150.00%
Total14100.00%2100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover9498.95%266.67%
Dan Carpenter11.05%133.33%
Total95100.00%3100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover3764.91%150.00%
Pavel Emelyanov2035.09%150.00%
Total57100.00%2100.00%


static int rds_loop_conn_path_connect(struct rds_conn_path *cp) { rds_connect_complete(cp->cp_conn); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover1571.43%150.00%
Sowmini Varadhan628.57%150.00%
Total21100.00%2100.00%


static void rds_loop_conn_path_shutdown(struct rds_conn_path *cp) { }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover770.00%150.00%
Sowmini Varadhan330.00%150.00%
Total10100.00%2100.00%


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); } }

Contributors

PersonTokensPropCommitsCommitProp
Andy Grover76100.00%1100.00%
Total76100.00%1100.00%

/* * 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_path = rds_loop_recv_path, .conn_alloc = rds_loop_conn_alloc, .conn_free = rds_loop_conn_free, .conn_path_connect = rds_loop_conn_path_connect, .conn_path_shutdown = rds_loop_conn_path_shutdown, .inc_copy_to_user = rds_message_inc_copy_to_user, .inc_free = rds_loop_inc_free, .t_name = "loopback", };

Overall Contributors

PersonTokensPropCommitsCommitProp
Andy Grover49683.08%433.33%
Neil Horman569.38%18.33%
Sowmini Varadhan213.52%433.33%
Pavel Emelyanov203.35%18.33%
Tejun Heo30.50%18.33%
Dan Carpenter10.17%18.33%
Total597100.00%12100.00%
Directory: net/rds
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