LU-9679 various: use list_splice and list_splice_init

The construct
   list_add(to, from);
   list_del(from);
is equivalent to
   list_splice(from, to);
providing 'to' has been initialized.
Similarly with list_del_init and list_splice_init.
There is no need to check if list_empty(from) first.

Also looping over a list moving individiual entries to
another list can more easily be done with list_splice.

These changes improve code clarity.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I710eb3bbd83c75e6c8f00b8d0a4c256ad28f9082
Reviewed-on: https://review.whamcloud.com/37457
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.super@gmail.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lnet/klnds/socklnd/socklnd.c b/lnet/klnds/socklnd/socklnd.c
index 96c16fd..4ed0458 100644 (file)
--- a/lnet/klnds/socklnd/socklnd.c
+++ b/lnet/klnds/socklnd/socklnd.c
@@ -1340,8 +1340,7 @@ failed_2:
        if (!peer_ni->ksnp_closing &&
            list_empty(&peer_ni->ksnp_conns) &&
            list_empty(&peer_ni->ksnp_routes)) {
-               list_add(&zombies, &peer_ni->ksnp_tx_queue);
-               list_del_init(&peer_ni->ksnp_tx_queue);
+               list_splice_init(&peer_ni->ksnp_tx_queue, &zombies);
                ksocknal_unlink_peer_locked(peer_ni);
        }
 
@@ -2141,11 +2140,10 @@ ksocknal_free_buffers (void)
        spin_lock(&ksocknal_data.ksnd_tx_lock);
 
        if (!list_empty(&ksocknal_data.ksnd_idle_noop_txs)) {
-               struct list_head zlist;
+               LIST_HEAD(zlist);
                struct ksock_tx *tx;
 
-               list_add(&zlist, &ksocknal_data.ksnd_idle_noop_txs);
-               list_del_init(&ksocknal_data.ksnd_idle_noop_txs);
+               list_splice_init(&ksocknal_data.ksnd_idle_noop_txs, &zlist);
                spin_unlock(&ksocknal_data.ksnd_tx_lock);
 
                while (!list_empty(&zlist)) {

diff --git a/lnet/klnds/socklnd/socklnd_cb.c b/lnet/klnds/socklnd/socklnd_cb.c
index f73039e..8675858 100644 (file)
--- a/lnet/klnds/socklnd/socklnd_cb.c
+++ b/lnet/klnds/socklnd/socklnd_cb.c
@@ -1545,11 +1545,7 @@ int ksocknal_scheduler(void *arg)
                if (!list_empty(&sched->kss_tx_conns)) {
                        LIST_HEAD(zlist);
 
-                       if (!list_empty(&sched->kss_zombie_noop_txs)) {
-                               list_add(&zlist,
-                                        &sched->kss_zombie_noop_txs);
-                               list_del_init(&sched->kss_zombie_noop_txs);
-                       }
+                       list_splice_init(&sched->kss_zombie_noop_txs, &zlist);
 
                        conn = list_entry(sched->kss_tx_conns.next,
                                          struct ksock_conn, ksnc_tx_list);
@@ -2643,14 +2639,11 @@ int ksocknal_reaper(void *arg)
                        ksocknal_destroy_conn(conn);
 
                        spin_lock_bh(&ksocknal_data.ksnd_reaper_lock);
-                        continue;
-                }
+                       continue;
+               }
 
-               if (!list_empty(&ksocknal_data.ksnd_enomem_conns)) {
-                       list_add(&enomem_conns,
-                                     &ksocknal_data.ksnd_enomem_conns);
-                       list_del_init(&ksocknal_data.ksnd_enomem_conns);
-                }
+               list_splice_init(&ksocknal_data.ksnd_enomem_conns,
+                                &enomem_conns);
 
                spin_unlock_bh(&ksocknal_data.ksnd_reaper_lock);
 

diff --git a/lnet/klnds/socklnd/socklnd_proto.c b/lnet/klnds/socklnd/socklnd_proto.c
index 33a92a5..14bdb45 100644 (file)
--- a/lnet/klnds/socklnd/socklnd_proto.c
+++ b/lnet/klnds/socklnd/socklnd_proto.c
@@ -146,11 +146,10 @@ ksocknal_queue_tx_msg_v2(struct ksock_conn *conn, struct ksock_tx *tx_msg)
         tx_msg->tx_msg.ksm_zc_cookies[1] = tx->tx_msg.ksm_zc_cookies[1];
         ksocknal_next_tx_carrier(conn);
 
-        /* use new_tx to replace the noop zc-ack packet */
-       list_add(&tx_msg->tx_list, &tx->tx_list);
-       list_del(&tx->tx_list);
+       /* use new_tx to replace the noop zc-ack packet */
+       list_splice(&tx->tx_list, &tx_msg->tx_list);
 
-        return tx;
+       return tx;
 }
 
 static int

diff --git a/lnet/lnet/api-ni.c b/lnet/lnet/api-ni.c
index d39e6b9..fbf3711 100644 (file)
--- a/lnet/lnet/api-ni.c
+++ b/lnet/lnet/api-ni.c
@@ -2152,16 +2152,12 @@ lnet_shutdown_lndnets(void)
        lnet_net_lock(LNET_LOCK_EX);
        the_lnet.ln_state = LNET_STATE_STOPPING;
 
-       while (!list_empty(&the_lnet.ln_nets)) {
-               /*
-                * move the nets to the zombie list to avoid them being
-                * picked up for new work. LONET is also included in the
-                * Nets that will be moved to the zombie list
-                */
-               net = list_entry(the_lnet.ln_nets.next,
-                                struct lnet_net, net_list);
-               list_move(&net->net_list, &the_lnet.ln_net_zombie);
-       }
+       /*
+        * move the nets to the zombie list to avoid them being
+        * picked up for new work. LONET is also included in the
+        * Nets that will be moved to the zombie list
+        */
+       list_splice_init(&the_lnet.ln_nets, &the_lnet.ln_net_zombie);
 
        /* Drop the cached loopback Net. */
        if (the_lnet.ln_loni != NULL) {

diff --git a/lnet/selftest/conrpc.c b/lnet/selftest/conrpc.c
index 8efacc0..39d19f0 100644 (file)
--- a/lnet/selftest/conrpc.c
+++ b/lnet/selftest/conrpc.c
@@ -1328,7 +1328,7 @@ lstcon_rpc_cleanup_wait(void)
        struct lstcon_rpc_trans *trans;
        struct lstcon_rpc *crpc;
        struct list_head *pacer;
-       struct list_head zlist;
+       LIST_HEAD(zlist);
 
        /* Called with hold of global mutex */
 
@@ -1362,8 +1362,7 @@ lstcon_rpc_cleanup_wait(void)
                        "waiting for %d console RPCs to being recycled\n",
                       atomic_read(&console_session.ses_rpc_counter));
 
-       list_add(&zlist, &console_session.ses_rpc_freelist);
-       list_del_init(&console_session.ses_rpc_freelist);
+       list_splice_init(&console_session.ses_rpc_freelist, &zlist);
 
        spin_unlock(&console_session.ses_rpc_lock);
 

diff --git a/lustre/ldlm/ldlm_lockd.c b/lustre/ldlm/ldlm_lockd.c
index 178976b..de04b6d 100644 (file)
--- a/lustre/ldlm/ldlm_lockd.c
+++ b/lustre/ldlm/ldlm_lockd.c
@@ -2146,8 +2146,7 @@ static inline void init_blwi(struct ldlm_bl_work_item *blwi,
        if (ld != NULL)
                blwi->blwi_ld = *ld;
        if (count) {
-               list_add(&blwi->blwi_head, cancels);
-               list_del_init(cancels);
+               list_splice_init(cancels, &blwi->blwi_head);
                blwi->blwi_count = count;
        } else {
                blwi->blwi_lock = lock;