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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  * 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,
                           u8 tos, 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 &&
             conn->c_tos == tos &&
             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;
     cp->cp_conn->c_proposed_version = RDS_PROTOCOL_VERSION;
     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, u8 tos,
                         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, tos, 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;
     conn->c_tos = tos;
 
 #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 (trans->t_prefer_loopback) {
             if (likely(is_outgoing)) {
                 /* "outgoing" connection to local address.
                  * Protocol says it wants the connection
                  * handled by the loopback transport.
                  * This is what TCP does.
                  */
                 trans = &rds_loop_transport;
             } else {
                 /* No transport currently in use
                  * should end up here, but if it
                  * does, reset/destroy the connection.
                  */
                 kfree(conn->c_path);
                 kmem_cache_free(rds_conn_slab, conn);
                 conn = ERR_PTR(-EOPNOTSUPP);
                 goto out;
             }
         }
     }
 
     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,
                     tos, 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, u8 tos,
                        gfp_t gfp, int dev_if)
 {
     return __rds_conn_create(net, laddr, faddr, trans, gfp, tos, 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,
                         u8 tos, gfp_t gfp, int dev_if)
 {
     return __rds_conn_create(net, laddr, faddr, trans, gfp, tos, 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];
     cinfo->tos = conn->c_tos;
     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);
 
 /* Check connectivity of all paths
  */
 void rds_check_all_paths(struct rds_connection *conn)
 {
     int i = 0;
 
     do {
         rds_conn_path_connect_if_down(&conn->c_path[i]);
     } while (++i < conn->c_npaths);
 }
 
 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);
 }

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