Merge branch 'net/rds/4.3-v3' of git://git.kernel.org/pub/scm/linux/kernel/git/ssanto...

[firefly-linux-kernel-4.4.55.git] / net / rds / bind.c

diff --git a/net/rds/bind.c b/net/rds/bind.c
index dd666fb9b4e1761a50fcf1fdf91ef508b55c4aca..bc6b93ecedb512bdcd75a9e765b2bd31cf2f0e81 100644 (file)
--- a/net/rds/bind.c
+++ b/net/rds/bind.c
@@ -38,48 +38,50 @@
 #include <linux/ratelimit.h>
 #include "rds.h"
 
+struct bind_bucket {
+       rwlock_t                lock;
+       struct hlist_head       head;
+};
+
 #define BIND_HASH_SIZE 1024
-static struct hlist_head bind_hash_table[BIND_HASH_SIZE];
-static DEFINE_SPINLOCK(rds_bind_lock);
+static struct bind_bucket bind_hash_table[BIND_HASH_SIZE];
 
-static struct hlist_head *hash_to_bucket(__be32 addr, __be16 port)
+static struct bind_bucket *hash_to_bucket(__be32 addr, __be16 port)
 {
        return bind_hash_table + (jhash_2words((u32)addr, (u32)port, 0) &
                                  (BIND_HASH_SIZE - 1));
 }
 
-static struct rds_sock *rds_bind_lookup(__be32 addr, __be16 port,
+/* must hold either read or write lock (write lock for insert != NULL) */
+static struct rds_sock *rds_bind_lookup(struct bind_bucket *bucket,
+                                       __be32 addr, __be16 port,
                                        struct rds_sock *insert)
 {
        struct rds_sock *rs;
-       struct hlist_head *head = hash_to_bucket(addr, port);
+       struct hlist_head *head = &bucket->head;
        u64 cmp;
        u64 needle = ((u64)be32_to_cpu(addr) << 32) | be16_to_cpu(port);
 
-       rcu_read_lock();
-       hlist_for_each_entry_rcu(rs, head, rs_bound_node) {
+       hlist_for_each_entry(rs, head, rs_bound_node) {
                cmp = ((u64)be32_to_cpu(rs->rs_bound_addr) << 32) |
                      be16_to_cpu(rs->rs_bound_port);
 
                if (cmp == needle) {
-                       rcu_read_unlock();
+                       rds_sock_addref(rs);
                        return rs;
                }
        }
-       rcu_read_unlock();
 
        if (insert) {
                /*
                 * make sure our addr and port are set before
-                * we are added to the list, other people
-                * in rcu will find us as soon as the
-                * hlist_add_head_rcu is done
+                * we are added to the list.
                 */
                insert->rs_bound_addr = addr;
                insert->rs_bound_port = port;
                rds_sock_addref(insert);
 
-               hlist_add_head_rcu(&insert->rs_bound_node, head);
+               hlist_add_head(&insert->rs_bound_node, head);
        }
        return NULL;
 }
@@ -93,16 +95,21 @@ static struct rds_sock *rds_bind_lookup(__be32 addr, __be16 port,
 struct rds_sock *rds_find_bound(__be32 addr, __be16 port)
 {
        struct rds_sock *rs;
+       unsigned long flags;
+       struct bind_bucket *bucket = hash_to_bucket(addr, port);
 
-       rs = rds_bind_lookup(addr, port, NULL);
+       read_lock_irqsave(&bucket->lock, flags);
+       rs = rds_bind_lookup(bucket, addr, port, NULL);
+       read_unlock_irqrestore(&bucket->lock, flags);
 
-       if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD))
-               rds_sock_addref(rs);
-       else
+       if (rs && sock_flag(rds_rs_to_sk(rs), SOCK_DEAD)) {
+               rds_sock_put(rs);
                rs = NULL;
+       }
 
        rdsdebug("returning rs %p for %pI4:%u\n", rs, &addr,
                ntohs(port));
+
        return rs;
 }
 
@@ -112,6 +119,7 @@ static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
        unsigned long flags;
        int ret = -EADDRINUSE;
        u16 rover, last;
+       struct bind_bucket *bucket;
 
        if (*port != 0) {
                rover = be16_to_cpu(*port);
@@ -121,42 +129,48 @@ static int rds_add_bound(struct rds_sock *rs, __be32 addr, __be16 *port)
                last = rover - 1;
        }
 
-       spin_lock_irqsave(&rds_bind_lock, flags);
-
        do {
+               struct rds_sock *rrs;
                if (rover == 0)
                        rover++;
-               if (!rds_bind_lookup(addr, cpu_to_be16(rover), rs)) {
+
+               bucket = hash_to_bucket(addr, cpu_to_be16(rover));
+               write_lock_irqsave(&bucket->lock, flags);
+               rrs = rds_bind_lookup(bucket, addr, cpu_to_be16(rover), rs);
+               write_unlock_irqrestore(&bucket->lock, flags);
+               if (!rrs) {
                        *port = rs->rs_bound_port;
                        ret = 0;
                        rdsdebug("rs %p binding to %pI4:%d\n",
                          rs, &addr, (int)ntohs(*port));
                        break;
+               } else {
+                       rds_sock_put(rrs);
                }
        } while (rover++ != last);
 
-       spin_unlock_irqrestore(&rds_bind_lock, flags);
-
        return ret;
 }
 
 void rds_remove_bound(struct rds_sock *rs)
 {
        unsigned long flags;
+       struct bind_bucket *bucket =
+               hash_to_bucket(rs->rs_bound_addr, rs->rs_bound_port);
 
-       spin_lock_irqsave(&rds_bind_lock, flags);
+       write_lock_irqsave(&bucket->lock, flags);
 
        if (rs->rs_bound_addr) {
                rdsdebug("rs %p unbinding from %pI4:%d\n",
                  rs, &rs->rs_bound_addr,
                  ntohs(rs->rs_bound_port));
 
-               hlist_del_init_rcu(&rs->rs_bound_node);
+               hlist_del_init(&rs->rs_bound_node);
                rds_sock_put(rs);
                rs->rs_bound_addr = 0;
        }
 
-       spin_unlock_irqrestore(&rds_bind_lock, flags);
+       write_unlock_irqrestore(&bucket->lock, flags);
 }
 
 int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
@@ -200,9 +214,13 @@ int rds_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 
 out:
        release_sock(sk);
-
-       /* we might have called rds_remove_bound on error */
-       if (ret)
-               synchronize_rcu();
        return ret;
 }
+
+void rds_bind_lock_init(void)
+{
+       int i;
+
+       for (i = 0; i < BIND_HASH_SIZE; i++)
+               rwlock_init(&bind_hash_table[i].lock);
+}