v4.19.13 snapshot.
diff --git a/net/rds/connection.c b/net/rds/connection.c
new file mode 100644
index 0000000..3bd2f4a
--- /dev/null
+++ b/net/rds/connection.c
@@ -0,0 +1,921 @@
+/*
+ * Copyright (c) 2006, 2018 Oracle and/or its affiliates. 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/list.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <net/ipv6.h>
+#include <net/inet6_hashtables.h>
+#include <net/addrconf.h>
+
+#include "rds.h"
+#include "loop.h"
+
+#define RDS_CONNECTION_HASH_BITS 12
+#define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS)
+#define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1)
+
+/* converting this to RCU is a chore for another day.. */
+static DEFINE_SPINLOCK(rds_conn_lock);
+static unsigned long rds_conn_count;
+static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
+static struct kmem_cache *rds_conn_slab;
+
+static struct hlist_head *rds_conn_bucket(const struct in6_addr *laddr,
+ const struct in6_addr *faddr)
+{
+ static u32 rds6_hash_secret __read_mostly;
+ static u32 rds_hash_secret __read_mostly;
+
+ u32 lhash, fhash, hash;
+
+ net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret));
+ net_get_random_once(&rds6_hash_secret, sizeof(rds6_hash_secret));
+
+ lhash = (__force u32)laddr->s6_addr32[3];
+#if IS_ENABLED(CONFIG_IPV6)
+ fhash = __ipv6_addr_jhash(faddr, rds6_hash_secret);
+#else
+ fhash = (__force u32)faddr->s6_addr32[3];
+#endif
+ hash = __inet_ehashfn(lhash, 0, fhash, 0, rds_hash_secret);
+
+ return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
+}
+
+#define rds_conn_info_set(var, test, suffix) do { \
+ if (test) \
+ var |= RDS_INFO_CONNECTION_FLAG_##suffix; \
+} while (0)
+
+/* rcu read lock must be held or the connection spinlock */
+static struct rds_connection *rds_conn_lookup(struct net *net,
+ struct hlist_head *head,
+ const struct in6_addr *laddr,
+ const struct in6_addr *faddr,
+ struct rds_transport *trans,
+ int dev_if)
+{
+ struct rds_connection *conn, *ret = NULL;
+
+ hlist_for_each_entry_rcu(conn, head, c_hash_node) {
+ if (ipv6_addr_equal(&conn->c_faddr, faddr) &&
+ ipv6_addr_equal(&conn->c_laddr, laddr) &&
+ conn->c_trans == trans &&
+ net == rds_conn_net(conn) &&
+ conn->c_dev_if == dev_if) {
+ ret = conn;
+ break;
+ }
+ }
+ rdsdebug("returning conn %p for %pI6c -> %pI6c\n", ret,
+ laddr, faddr);
+ return ret;
+}
+
+/*
+ * This is called by transports as they're bringing down a connection.
+ * It clears partial message state so that the transport can start sending
+ * and receiving over this connection again in the future. It is up to
+ * the transport to have serialized this call with its send and recv.
+ */
+static void rds_conn_path_reset(struct rds_conn_path *cp)
+{
+ struct rds_connection *conn = cp->cp_conn;
+
+ rdsdebug("connection %pI6c to %pI6c reset\n",
+ &conn->c_laddr, &conn->c_faddr);
+
+ rds_stats_inc(s_conn_reset);
+ rds_send_path_reset(cp);
+ cp->cp_flags = 0;
+
+ /* Do not clear next_rx_seq here, else we cannot distinguish
+ * retransmitted packets from new packets, and will hand all
+ * of them to the application. That is not consistent with the
+ * reliability guarantees of RDS. */
+}
+
+static void __rds_conn_path_init(struct rds_connection *conn,
+ struct rds_conn_path *cp, bool is_outgoing)
+{
+ spin_lock_init(&cp->cp_lock);
+ cp->cp_next_tx_seq = 1;
+ init_waitqueue_head(&cp->cp_waitq);
+ INIT_LIST_HEAD(&cp->cp_send_queue);
+ INIT_LIST_HEAD(&cp->cp_retrans);
+
+ cp->cp_conn = conn;
+ atomic_set(&cp->cp_state, RDS_CONN_DOWN);
+ cp->cp_send_gen = 0;
+ cp->cp_reconnect_jiffies = 0;
+ INIT_DELAYED_WORK(&cp->cp_send_w, rds_send_worker);
+ INIT_DELAYED_WORK(&cp->cp_recv_w, rds_recv_worker);
+ INIT_DELAYED_WORK(&cp->cp_conn_w, rds_connect_worker);
+ INIT_WORK(&cp->cp_down_w, rds_shutdown_worker);
+ mutex_init(&cp->cp_cm_lock);
+ cp->cp_flags = 0;
+}
+
+/*
+ * There is only every one 'conn' for a given pair of addresses in the
+ * system at a time. They contain messages to be retransmitted and so
+ * span the lifetime of the actual underlying transport connections.
+ *
+ * For now they are not garbage collected once they're created. They
+ * are torn down as the module is removed, if ever.
+ */
+static struct rds_connection *__rds_conn_create(struct net *net,
+ const struct in6_addr *laddr,
+ const struct in6_addr *faddr,
+ struct rds_transport *trans,
+ gfp_t gfp,
+ int is_outgoing,
+ int dev_if)
+{
+ struct rds_connection *conn, *parent = NULL;
+ struct hlist_head *head = rds_conn_bucket(laddr, faddr);
+ struct rds_transport *loop_trans;
+ unsigned long flags;
+ int ret, i;
+ int npaths = (trans->t_mp_capable ? RDS_MPATH_WORKERS : 1);
+
+ rcu_read_lock();
+ conn = rds_conn_lookup(net, head, laddr, faddr, trans, dev_if);
+ if (conn &&
+ conn->c_loopback &&
+ conn->c_trans != &rds_loop_transport &&
+ ipv6_addr_equal(laddr, faddr) &&
+ !is_outgoing) {
+ /* This is a looped back IB connection, and we're
+ * called by the code handling the incoming connect.
+ * We need a second connection object into which we
+ * can stick the other QP. */
+ parent = conn;
+ conn = parent->c_passive;
+ }
+ rcu_read_unlock();
+ if (conn)
+ goto out;
+
+ conn = kmem_cache_zalloc(rds_conn_slab, gfp);
+ if (!conn) {
+ conn = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+ conn->c_path = kcalloc(npaths, sizeof(struct rds_conn_path), gfp);
+ if (!conn->c_path) {
+ kmem_cache_free(rds_conn_slab, conn);
+ conn = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ INIT_HLIST_NODE(&conn->c_hash_node);
+ conn->c_laddr = *laddr;
+ conn->c_isv6 = !ipv6_addr_v4mapped(laddr);
+ conn->c_faddr = *faddr;
+ conn->c_dev_if = dev_if;
+
+#if IS_ENABLED(CONFIG_IPV6)
+ /* If the local address is link local, set c_bound_if to be the
+ * index used for this connection. Otherwise, set it to 0 as
+ * the socket is not bound to an interface. c_bound_if is used
+ * to look up a socket when a packet is received
+ */
+ if (ipv6_addr_type(laddr) & IPV6_ADDR_LINKLOCAL)
+ conn->c_bound_if = dev_if;
+ else
+#endif
+ conn->c_bound_if = 0;
+
+ rds_conn_net_set(conn, net);
+
+ ret = rds_cong_get_maps(conn);
+ if (ret) {
+ kfree(conn->c_path);
+ kmem_cache_free(rds_conn_slab, conn);
+ conn = ERR_PTR(ret);
+ goto out;
+ }
+
+ /*
+ * This is where a connection becomes loopback. If *any* RDS sockets
+ * can bind to the destination address then we'd rather the messages
+ * flow through loopback rather than either transport.
+ */
+ loop_trans = rds_trans_get_preferred(net, faddr, conn->c_dev_if);
+ if (loop_trans) {
+ rds_trans_put(loop_trans);
+ conn->c_loopback = 1;
+ if (is_outgoing && trans->t_prefer_loopback) {
+ /* "outgoing" connection - and the transport
+ * says it wants the connection handled by the
+ * loopback transport. This is what TCP does.
+ */
+ trans = &rds_loop_transport;
+ }
+ }
+
+ conn->c_trans = trans;
+
+ init_waitqueue_head(&conn->c_hs_waitq);
+ for (i = 0; i < npaths; i++) {
+ __rds_conn_path_init(conn, &conn->c_path[i],
+ is_outgoing);
+ conn->c_path[i].cp_index = i;
+ }
+ rcu_read_lock();
+ if (rds_destroy_pending(conn))
+ ret = -ENETDOWN;
+ else
+ ret = trans->conn_alloc(conn, GFP_ATOMIC);
+ if (ret) {
+ rcu_read_unlock();
+ kfree(conn->c_path);
+ kmem_cache_free(rds_conn_slab, conn);
+ conn = ERR_PTR(ret);
+ goto out;
+ }
+
+ rdsdebug("allocated conn %p for %pI6c -> %pI6c over %s %s\n",
+ conn, laddr, faddr,
+ strnlen(trans->t_name, sizeof(trans->t_name)) ?
+ trans->t_name : "[unknown]", is_outgoing ? "(outgoing)" : "");
+
+ /*
+ * Since we ran without holding the conn lock, someone could
+ * have created the same conn (either normal or passive) in the
+ * interim. We check while holding the lock. If we won, we complete
+ * init and return our conn. If we lost, we rollback and return the
+ * other one.
+ */
+ spin_lock_irqsave(&rds_conn_lock, flags);
+ if (parent) {
+ /* Creating passive conn */
+ if (parent->c_passive) {
+ trans->conn_free(conn->c_path[0].cp_transport_data);
+ kfree(conn->c_path);
+ kmem_cache_free(rds_conn_slab, conn);
+ conn = parent->c_passive;
+ } else {
+ parent->c_passive = conn;
+ rds_cong_add_conn(conn);
+ rds_conn_count++;
+ }
+ } else {
+ /* Creating normal conn */
+ struct rds_connection *found;
+
+ found = rds_conn_lookup(net, head, laddr, faddr, trans,
+ dev_if);
+ if (found) {
+ struct rds_conn_path *cp;
+ int i;
+
+ for (i = 0; i < npaths; i++) {
+ cp = &conn->c_path[i];
+ /* The ->conn_alloc invocation may have
+ * allocated resource for all paths, so all
+ * of them may have to be freed here.
+ */
+ if (cp->cp_transport_data)
+ trans->conn_free(cp->cp_transport_data);
+ }
+ kfree(conn->c_path);
+ kmem_cache_free(rds_conn_slab, conn);
+ conn = found;
+ } else {
+ conn->c_my_gen_num = rds_gen_num;
+ conn->c_peer_gen_num = 0;
+ hlist_add_head_rcu(&conn->c_hash_node, head);
+ rds_cong_add_conn(conn);
+ rds_conn_count++;
+ }
+ }
+ spin_unlock_irqrestore(&rds_conn_lock, flags);
+ rcu_read_unlock();
+
+out:
+ return conn;
+}
+
+struct rds_connection *rds_conn_create(struct net *net,
+ const struct in6_addr *laddr,
+ const struct in6_addr *faddr,
+ struct rds_transport *trans, gfp_t gfp,
+ int dev_if)
+{
+ return __rds_conn_create(net, laddr, faddr, trans, gfp, 0, dev_if);
+}
+EXPORT_SYMBOL_GPL(rds_conn_create);
+
+struct rds_connection *rds_conn_create_outgoing(struct net *net,
+ const struct in6_addr *laddr,
+ const struct in6_addr *faddr,
+ struct rds_transport *trans,
+ gfp_t gfp, int dev_if)
+{
+ return __rds_conn_create(net, laddr, faddr, trans, gfp, 1, dev_if);
+}
+EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
+
+void rds_conn_shutdown(struct rds_conn_path *cp)
+{
+ struct rds_connection *conn = cp->cp_conn;
+
+ /* shut it down unless it's down already */
+ if (!rds_conn_path_transition(cp, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
+ /*
+ * Quiesce the connection mgmt handlers before we start tearing
+ * things down. We don't hold the mutex for the entire
+ * duration of the shutdown operation, else we may be
+ * deadlocking with the CM handler. Instead, the CM event
+ * handler is supposed to check for state DISCONNECTING
+ */
+ mutex_lock(&cp->cp_cm_lock);
+ if (!rds_conn_path_transition(cp, RDS_CONN_UP,
+ RDS_CONN_DISCONNECTING) &&
+ !rds_conn_path_transition(cp, RDS_CONN_ERROR,
+ RDS_CONN_DISCONNECTING)) {
+ rds_conn_path_error(cp,
+ "shutdown called in state %d\n",
+ atomic_read(&cp->cp_state));
+ mutex_unlock(&cp->cp_cm_lock);
+ return;
+ }
+ mutex_unlock(&cp->cp_cm_lock);
+
+ wait_event(cp->cp_waitq,
+ !test_bit(RDS_IN_XMIT, &cp->cp_flags));
+ wait_event(cp->cp_waitq,
+ !test_bit(RDS_RECV_REFILL, &cp->cp_flags));
+
+ conn->c_trans->conn_path_shutdown(cp);
+ rds_conn_path_reset(cp);
+
+ if (!rds_conn_path_transition(cp, RDS_CONN_DISCONNECTING,
+ RDS_CONN_DOWN) &&
+ !rds_conn_path_transition(cp, RDS_CONN_ERROR,
+ RDS_CONN_DOWN)) {
+ /* This can happen - eg when we're in the middle of tearing
+ * down the connection, and someone unloads the rds module.
+ * Quite reproducible with loopback connections.
+ * Mostly harmless.
+ *
+ * Note that this also happens with rds-tcp because
+ * we could have triggered rds_conn_path_drop in irq
+ * mode from rds_tcp_state change on the receipt of
+ * a FIN, thus we need to recheck for RDS_CONN_ERROR
+ * here.
+ */
+ rds_conn_path_error(cp, "%s: failed to transition "
+ "to state DOWN, current state "
+ "is %d\n", __func__,
+ atomic_read(&cp->cp_state));
+ return;
+ }
+ }
+
+ /* Then reconnect if it's still live.
+ * The passive side of an IB loopback connection is never added
+ * to the conn hash, so we never trigger a reconnect on this
+ * conn - the reconnect is always triggered by the active peer. */
+ cancel_delayed_work_sync(&cp->cp_conn_w);
+ rcu_read_lock();
+ if (!hlist_unhashed(&conn->c_hash_node)) {
+ rcu_read_unlock();
+ rds_queue_reconnect(cp);
+ } else {
+ rcu_read_unlock();
+ }
+}
+
+/* destroy a single rds_conn_path. rds_conn_destroy() iterates over
+ * all paths using rds_conn_path_destroy()
+ */
+static void rds_conn_path_destroy(struct rds_conn_path *cp)
+{
+ struct rds_message *rm, *rtmp;
+
+ if (!cp->cp_transport_data)
+ return;
+
+ /* make sure lingering queued work won't try to ref the conn */
+ cancel_delayed_work_sync(&cp->cp_send_w);
+ cancel_delayed_work_sync(&cp->cp_recv_w);
+
+ rds_conn_path_drop(cp, true);
+ flush_work(&cp->cp_down_w);
+
+ /* tear down queued messages */
+ list_for_each_entry_safe(rm, rtmp,
+ &cp->cp_send_queue,
+ m_conn_item) {
+ list_del_init(&rm->m_conn_item);
+ BUG_ON(!list_empty(&rm->m_sock_item));
+ rds_message_put(rm);
+ }
+ if (cp->cp_xmit_rm)
+ rds_message_put(cp->cp_xmit_rm);
+
+ WARN_ON(delayed_work_pending(&cp->cp_send_w));
+ WARN_ON(delayed_work_pending(&cp->cp_recv_w));
+ WARN_ON(delayed_work_pending(&cp->cp_conn_w));
+ WARN_ON(work_pending(&cp->cp_down_w));
+
+ cp->cp_conn->c_trans->conn_free(cp->cp_transport_data);
+}
+
+/*
+ * Stop and free a connection.
+ *
+ * This can only be used in very limited circumstances. It assumes that once
+ * the conn has been shutdown that no one else is referencing the connection.
+ * We can only ensure this in the rmmod path in the current code.
+ */
+void rds_conn_destroy(struct rds_connection *conn)
+{
+ unsigned long flags;
+ int i;
+ struct rds_conn_path *cp;
+ int npaths = (conn->c_trans->t_mp_capable ? RDS_MPATH_WORKERS : 1);
+
+ rdsdebug("freeing conn %p for %pI4 -> "
+ "%pI4\n", conn, &conn->c_laddr,
+ &conn->c_faddr);
+
+ /* Ensure conn will not be scheduled for reconnect */
+ spin_lock_irq(&rds_conn_lock);
+ hlist_del_init_rcu(&conn->c_hash_node);
+ spin_unlock_irq(&rds_conn_lock);
+ synchronize_rcu();
+
+ /* shut the connection down */
+ for (i = 0; i < npaths; i++) {
+ cp = &conn->c_path[i];
+ rds_conn_path_destroy(cp);
+ BUG_ON(!list_empty(&cp->cp_retrans));
+ }
+
+ /*
+ * The congestion maps aren't freed up here. They're
+ * freed by rds_cong_exit() after all the connections
+ * have been freed.
+ */
+ rds_cong_remove_conn(conn);
+
+ kfree(conn->c_path);
+ kmem_cache_free(rds_conn_slab, conn);
+
+ spin_lock_irqsave(&rds_conn_lock, flags);
+ rds_conn_count--;
+ spin_unlock_irqrestore(&rds_conn_lock, flags);
+}
+EXPORT_SYMBOL_GPL(rds_conn_destroy);
+
+static void __rds_inc_msg_cp(struct rds_incoming *inc,
+ struct rds_info_iterator *iter,
+ void *saddr, void *daddr, int flip, bool isv6)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+ if (isv6)
+ rds6_inc_info_copy(inc, iter, saddr, daddr, flip);
+ else
+#endif
+ rds_inc_info_copy(inc, iter, *(__be32 *)saddr,
+ *(__be32 *)daddr, flip);
+}
+
+static void rds_conn_message_info_cmn(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens,
+ int want_send, bool isv6)
+{
+ struct hlist_head *head;
+ struct list_head *list;
+ struct rds_connection *conn;
+ struct rds_message *rm;
+ unsigned int total = 0;
+ unsigned long flags;
+ size_t i;
+ int j;
+
+ if (isv6)
+ len /= sizeof(struct rds6_info_message);
+ else
+ len /= sizeof(struct rds_info_message);
+
+ rcu_read_lock();
+
+ for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
+ i++, head++) {
+ hlist_for_each_entry_rcu(conn, head, c_hash_node) {
+ struct rds_conn_path *cp;
+ int npaths;
+
+ if (!isv6 && conn->c_isv6)
+ continue;
+
+ npaths = (conn->c_trans->t_mp_capable ?
+ RDS_MPATH_WORKERS : 1);
+
+ for (j = 0; j < npaths; j++) {
+ cp = &conn->c_path[j];
+ if (want_send)
+ list = &cp->cp_send_queue;
+ else
+ list = &cp->cp_retrans;
+
+ spin_lock_irqsave(&cp->cp_lock, flags);
+
+ /* XXX too lazy to maintain counts.. */
+ list_for_each_entry(rm, list, m_conn_item) {
+ total++;
+ if (total <= len)
+ __rds_inc_msg_cp(&rm->m_inc,
+ iter,
+ &conn->c_laddr,
+ &conn->c_faddr,
+ 0, isv6);
+ }
+
+ spin_unlock_irqrestore(&cp->cp_lock, flags);
+ }
+ }
+ }
+ rcu_read_unlock();
+
+ lens->nr = total;
+ if (isv6)
+ lens->each = sizeof(struct rds6_info_message);
+ else
+ lens->each = sizeof(struct rds_info_message);
+}
+
+static void rds_conn_message_info(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens,
+ int want_send)
+{
+ rds_conn_message_info_cmn(sock, len, iter, lens, want_send, false);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static void rds6_conn_message_info(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens,
+ int want_send)
+{
+ rds_conn_message_info_cmn(sock, len, iter, lens, want_send, true);
+}
+#endif
+
+static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens)
+{
+ rds_conn_message_info(sock, len, iter, lens, 1);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static void rds6_conn_message_info_send(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens)
+{
+ rds6_conn_message_info(sock, len, iter, lens, 1);
+}
+#endif
+
+static void rds_conn_message_info_retrans(struct socket *sock,
+ unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens)
+{
+ rds_conn_message_info(sock, len, iter, lens, 0);
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static void rds6_conn_message_info_retrans(struct socket *sock,
+ unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens)
+{
+ rds6_conn_message_info(sock, len, iter, lens, 0);
+}
+#endif
+
+void rds_for_each_conn_info(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens,
+ int (*visitor)(struct rds_connection *, void *),
+ u64 *buffer,
+ size_t item_len)
+{
+ struct hlist_head *head;
+ struct rds_connection *conn;
+ size_t i;
+
+ rcu_read_lock();
+
+ lens->nr = 0;
+ lens->each = item_len;
+
+ for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
+ i++, head++) {
+ hlist_for_each_entry_rcu(conn, head, c_hash_node) {
+
+ /* XXX no c_lock usage.. */
+ if (!visitor(conn, buffer))
+ continue;
+
+ /* We copy as much as we can fit in the buffer,
+ * but we count all items so that the caller
+ * can resize the buffer. */
+ if (len >= item_len) {
+ rds_info_copy(iter, buffer, item_len);
+ len -= item_len;
+ }
+ lens->nr++;
+ }
+ }
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
+
+static void rds_walk_conn_path_info(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens,
+ int (*visitor)(struct rds_conn_path *, void *),
+ u64 *buffer,
+ size_t item_len)
+{
+ struct hlist_head *head;
+ struct rds_connection *conn;
+ size_t i;
+
+ rcu_read_lock();
+
+ lens->nr = 0;
+ lens->each = item_len;
+
+ for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
+ i++, head++) {
+ hlist_for_each_entry_rcu(conn, head, c_hash_node) {
+ struct rds_conn_path *cp;
+
+ /* XXX We only copy the information from the first
+ * path for now. The problem is that if there are
+ * more than one underlying paths, we cannot report
+ * information of all of them using the existing
+ * API. For example, there is only one next_tx_seq,
+ * which path's next_tx_seq should we report? It is
+ * a bug in the design of MPRDS.
+ */
+ cp = conn->c_path;
+
+ /* XXX no cp_lock usage.. */
+ if (!visitor(cp, buffer))
+ continue;
+
+ /* We copy as much as we can fit in the buffer,
+ * but we count all items so that the caller
+ * can resize the buffer.
+ */
+ if (len >= item_len) {
+ rds_info_copy(iter, buffer, item_len);
+ len -= item_len;
+ }
+ lens->nr++;
+ }
+ }
+ rcu_read_unlock();
+}
+
+static int rds_conn_info_visitor(struct rds_conn_path *cp, void *buffer)
+{
+ struct rds_info_connection *cinfo = buffer;
+ struct rds_connection *conn = cp->cp_conn;
+
+ if (conn->c_isv6)
+ return 0;
+
+ cinfo->next_tx_seq = cp->cp_next_tx_seq;
+ cinfo->next_rx_seq = cp->cp_next_rx_seq;
+ cinfo->laddr = conn->c_laddr.s6_addr32[3];
+ cinfo->faddr = conn->c_faddr.s6_addr32[3];
+ strncpy(cinfo->transport, conn->c_trans->t_name,
+ sizeof(cinfo->transport));
+ cinfo->flags = 0;
+
+ rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &cp->cp_flags),
+ SENDING);
+ /* XXX Future: return the state rather than these funky bits */
+ rds_conn_info_set(cinfo->flags,
+ atomic_read(&cp->cp_state) == RDS_CONN_CONNECTING,
+ CONNECTING);
+ rds_conn_info_set(cinfo->flags,
+ atomic_read(&cp->cp_state) == RDS_CONN_UP,
+ CONNECTED);
+ return 1;
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static int rds6_conn_info_visitor(struct rds_conn_path *cp, void *buffer)
+{
+ struct rds6_info_connection *cinfo6 = buffer;
+ struct rds_connection *conn = cp->cp_conn;
+
+ cinfo6->next_tx_seq = cp->cp_next_tx_seq;
+ cinfo6->next_rx_seq = cp->cp_next_rx_seq;
+ cinfo6->laddr = conn->c_laddr;
+ cinfo6->faddr = conn->c_faddr;
+ strncpy(cinfo6->transport, conn->c_trans->t_name,
+ sizeof(cinfo6->transport));
+ cinfo6->flags = 0;
+
+ rds_conn_info_set(cinfo6->flags, test_bit(RDS_IN_XMIT, &cp->cp_flags),
+ SENDING);
+ /* XXX Future: return the state rather than these funky bits */
+ rds_conn_info_set(cinfo6->flags,
+ atomic_read(&cp->cp_state) == RDS_CONN_CONNECTING,
+ CONNECTING);
+ rds_conn_info_set(cinfo6->flags,
+ atomic_read(&cp->cp_state) == RDS_CONN_UP,
+ CONNECTED);
+ /* Just return 1 as there is no error case. This is a helper function
+ * for rds_walk_conn_path_info() and it wants a return value.
+ */
+ return 1;
+}
+#endif
+
+static void rds_conn_info(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens)
+{
+ u64 buffer[(sizeof(struct rds_info_connection) + 7) / 8];
+
+ rds_walk_conn_path_info(sock, len, iter, lens,
+ rds_conn_info_visitor,
+ buffer,
+ sizeof(struct rds_info_connection));
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static void rds6_conn_info(struct socket *sock, unsigned int len,
+ struct rds_info_iterator *iter,
+ struct rds_info_lengths *lens)
+{
+ u64 buffer[(sizeof(struct rds6_info_connection) + 7) / 8];
+
+ rds_walk_conn_path_info(sock, len, iter, lens,
+ rds6_conn_info_visitor,
+ buffer,
+ sizeof(struct rds6_info_connection));
+}
+#endif
+
+int rds_conn_init(void)
+{
+ int ret;
+
+ ret = rds_loop_net_init(); /* register pernet callback */
+ if (ret)
+ return ret;
+
+ rds_conn_slab = kmem_cache_create("rds_connection",
+ sizeof(struct rds_connection),
+ 0, 0, NULL);
+ if (!rds_conn_slab) {
+ rds_loop_net_exit();
+ return -ENOMEM;
+ }
+
+ rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
+ rds_info_register_func(RDS_INFO_SEND_MESSAGES,
+ rds_conn_message_info_send);
+ rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
+ rds_conn_message_info_retrans);
+#if IS_ENABLED(CONFIG_IPV6)
+ rds_info_register_func(RDS6_INFO_CONNECTIONS, rds6_conn_info);
+ rds_info_register_func(RDS6_INFO_SEND_MESSAGES,
+ rds6_conn_message_info_send);
+ rds_info_register_func(RDS6_INFO_RETRANS_MESSAGES,
+ rds6_conn_message_info_retrans);
+#endif
+ return 0;
+}
+
+void rds_conn_exit(void)
+{
+ rds_loop_net_exit(); /* unregister pernet callback */
+ rds_loop_exit();
+
+ WARN_ON(!hlist_empty(rds_conn_hash));
+
+ kmem_cache_destroy(rds_conn_slab);
+
+ rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
+ rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
+ rds_conn_message_info_send);
+ rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
+ rds_conn_message_info_retrans);
+#if IS_ENABLED(CONFIG_IPV6)
+ rds_info_deregister_func(RDS6_INFO_CONNECTIONS, rds6_conn_info);
+ rds_info_deregister_func(RDS6_INFO_SEND_MESSAGES,
+ rds6_conn_message_info_send);
+ rds_info_deregister_func(RDS6_INFO_RETRANS_MESSAGES,
+ rds6_conn_message_info_retrans);
+#endif
+}
+
+/*
+ * Force a disconnect
+ */
+void rds_conn_path_drop(struct rds_conn_path *cp, bool destroy)
+{
+ atomic_set(&cp->cp_state, RDS_CONN_ERROR);
+
+ rcu_read_lock();
+ if (!destroy && rds_destroy_pending(cp->cp_conn)) {
+ rcu_read_unlock();
+ return;
+ }
+ queue_work(rds_wq, &cp->cp_down_w);
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(rds_conn_path_drop);
+
+void rds_conn_drop(struct rds_connection *conn)
+{
+ WARN_ON(conn->c_trans->t_mp_capable);
+ rds_conn_path_drop(&conn->c_path[0], false);
+}
+EXPORT_SYMBOL_GPL(rds_conn_drop);
+
+/*
+ * If the connection is down, trigger a connect. We may have scheduled a
+ * delayed reconnect however - in this case we should not interfere.
+ */
+void rds_conn_path_connect_if_down(struct rds_conn_path *cp)
+{
+ rcu_read_lock();
+ if (rds_destroy_pending(cp->cp_conn)) {
+ rcu_read_unlock();
+ return;
+ }
+ if (rds_conn_path_state(cp) == RDS_CONN_DOWN &&
+ !test_and_set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags))
+ queue_delayed_work(rds_wq, &cp->cp_conn_w, 0);
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(rds_conn_path_connect_if_down);
+
+void rds_conn_connect_if_down(struct rds_connection *conn)
+{
+ WARN_ON(conn->c_trans->t_mp_capable);
+ rds_conn_path_connect_if_down(&conn->c_path[0]);
+}
+EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
+
+void
+__rds_conn_path_error(struct rds_conn_path *cp, const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ vprintk(fmt, ap);
+ va_end(ap);
+
+ rds_conn_path_drop(cp, false);
+}