[PATCH 35/38] tipc: Convert conn_idr to XArray

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <wi...@infradead.org>

Replace idr_lock with the internal XArray lock.  The idr_in_use
counter isn't needed as we can free all the elements in the array
without it.

Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 net/tipc/topsrv.c | 49 ++++++++++++++---------------------------------
 1 file changed, 14 insertions(+), 35 deletions(-)

diff --git a/net/tipc/topsrv.c b/net/tipc/topsrv.c
index 3a12fc18239b..72b3180e0ea5 100644
--- a/net/tipc/topsrv.c
+++ b/net/tipc/topsrv.c
@@ -54,9 +54,7 @@
 
 /**
  * struct tipc_topsrv - TIPC server structure
- * @conn_idr: identifier set of connection
- * @idr_lock: protect the connection identifier set
- * @idr_in_use: amount of allocated identifier entry
+ * @conns: identifier set of connection
  * @net: network namspace instance
  * @awork: accept work item
  * @rcv_wq: receive workqueue
@@ -65,9 +63,7 @@
  * @name: server name
  */
 struct tipc_topsrv {
-       struct idr conn_idr;
-       spinlock_t idr_lock; /* for idr list */
-       int idr_in_use;
+       struct xarray conns;
        struct net *net;
        struct work_struct awork;
        struct workqueue_struct *rcv_wq;
@@ -127,10 +123,7 @@ static void tipc_conn_kref_release(struct kref *kref)
        struct tipc_topsrv *s = con->server;
        struct outqueue_entry *e, *safe;
 
-       spin_lock_bh(&s->idr_lock);
-       idr_remove(&s->conn_idr, con->conid);
-       s->idr_in_use--;
-       spin_unlock_bh(&s->idr_lock);
+       xa_erase_bh(&s->conns, con->conid);
        if (con->sock)
                sock_release(con->sock);
 
@@ -194,16 +187,12 @@ static struct tipc_conn *tipc_conn_alloc(struct 
tipc_topsrv *s)
        INIT_WORK(&con->swork, tipc_conn_send_work);
        INIT_WORK(&con->rwork, tipc_conn_recv_work);
 
-       spin_lock_bh(&s->idr_lock);
-       ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
+       ret = xa_alloc_bh(&s->conns, &con->conid, con, xa_limit_32b,
+                       GFP_ATOMIC);
        if (ret < 0) {
                kfree(con);
-               spin_unlock_bh(&s->idr_lock);
                return ERR_PTR(-ENOMEM);
        }
-       con->conid = ret;
-       s->idr_in_use++;
-       spin_unlock_bh(&s->idr_lock);
 
        set_bit(CF_CONNECTED, &con->flags);
        con->server = s;
@@ -215,11 +204,11 @@ static struct tipc_conn *tipc_conn_lookup(struct 
tipc_topsrv *s, int conid)
 {
        struct tipc_conn *con;
 
-       spin_lock_bh(&s->idr_lock);
-       con = idr_find(&s->conn_idr, conid);
+       xa_lock_bh(&s->conns);
+       con = xa_load(&s->conns, conid);
        if (!connected(con) || !kref_get_unless_zero(&con->kref))
                con = NULL;
-       spin_unlock_bh(&s->idr_lock);
+       xa_unlock_bh(&s->conns);
        return con;
 }
 
@@ -655,9 +644,7 @@ static int tipc_topsrv_start(struct net *net)
        tn->topsrv = srv;
        atomic_set(&tn->subscription_count, 0);
 
-       spin_lock_init(&srv->idr_lock);
-       idr_init(&srv->conn_idr);
-       srv->idr_in_use = 0;
+       xa_init_flags(&srv->conns, XA_FLAGS_ALLOC | XA_FLAGS_LOCK_BH);
 
        ret = tipc_topsrv_work_start(srv);
        if (ret < 0)
@@ -675,24 +662,16 @@ static void tipc_topsrv_stop(struct net *net)
        struct tipc_topsrv *srv = tipc_topsrv(net);
        struct socket *lsock = srv->listener;
        struct tipc_conn *con;
-       int id;
-
-       spin_lock_bh(&srv->idr_lock);
-       for (id = 0; srv->idr_in_use; id++) {
-               con = idr_find(&srv->conn_idr, id);
-               if (con) {
-                       spin_unlock_bh(&srv->idr_lock);
-                       tipc_conn_close(con);
-                       spin_lock_bh(&srv->idr_lock);
-               }
-       }
+       unsigned long id;
+
+       xa_for_each(&srv->conns, id, con)
+               tipc_conn_close(con);
+
        __module_get(lsock->ops->owner);
        __module_get(lsock->sk->sk_prot_creator->owner);
        srv->listener = NULL;
-       spin_unlock_bh(&srv->idr_lock);
        sock_release(lsock);
        tipc_topsrv_work_stop(srv);
-       idr_destroy(&srv->conn_idr);
        kfree(srv);
 }
 
-- 
2.23.0.rc1