af_unix: Acquire/Release per-netns hash table's locks.

This commit adds extra spin_lock/spin_unlock() for a per-netns
hash table inside the existing ones for unix_table_locks.

As of this commit, sockets are still linked in the global hash
table.  After putting sockets in a per-netns hash table and
removing the old one in the next patch, we remove the global
locks in the last patch.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index cdd1288..79f8fc5 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -158,7 +158,8 @@ static unsigned int unix_abstract_hash(struct sockaddr_un *sunaddr,
        return hash & UNIX_HASH_MOD;
 }
 
-static void unix_table_double_lock(unsigned int hash1, unsigned int hash2)
+static void unix_table_double_lock(struct net *net,
+                                  unsigned int hash1, unsigned int hash2)
 {
        /* hash1 and hash2 is never the same because
         * one is between 0 and UNIX_HASH_MOD, and
@@ -169,10 +170,17 @@ static void unix_table_double_lock(unsigned int hash1, unsigned int hash2)
 
        spin_lock(&unix_table_locks[hash1]);
        spin_lock_nested(&unix_table_locks[hash2], SINGLE_DEPTH_NESTING);
+
+       spin_lock(&net->unx.table.locks[hash1]);
+       spin_lock_nested(&net->unx.table.locks[hash2], SINGLE_DEPTH_NESTING);
 }
 
-static void unix_table_double_unlock(unsigned int hash1, unsigned int hash2)
+static void unix_table_double_unlock(struct net *net,
+                                    unsigned int hash1, unsigned int hash2)
 {
+       spin_unlock(&net->unx.table.locks[hash1]);
+       spin_unlock(&net->unx.table.locks[hash2]);
+
        spin_unlock(&unix_table_locks[hash1]);
        spin_unlock(&unix_table_locks[hash2]);
 }
@@ -316,17 +324,21 @@ static void __unix_set_addr_hash(struct sock *sk, struct unix_address *addr,
        __unix_insert_socket(sk);
 }
 
-static void unix_remove_socket(struct sock *sk)
+static void unix_remove_socket(struct net *net, struct sock *sk)
 {
        spin_lock(&unix_table_locks[sk->sk_hash]);
+       spin_lock(&net->unx.table.locks[sk->sk_hash]);
        __unix_remove_socket(sk);
+       spin_unlock(&net->unx.table.locks[sk->sk_hash]);
        spin_unlock(&unix_table_locks[sk->sk_hash]);
 }
 
-static void unix_insert_unbound_socket(struct sock *sk)
+static void unix_insert_unbound_socket(struct net *net, struct sock *sk)
 {
        spin_lock(&unix_table_locks[sk->sk_hash]);
+       spin_lock(&net->unx.table.locks[sk->sk_hash]);
        __unix_insert_socket(sk);
+       spin_unlock(&net->unx.table.locks[sk->sk_hash]);
        spin_unlock(&unix_table_locks[sk->sk_hash]);
 }
 
@@ -356,28 +368,33 @@ static inline struct sock *unix_find_socket_byname(struct net *net,
        struct sock *s;
 
        spin_lock(&unix_table_locks[hash]);
+       spin_lock(&net->unx.table.locks[hash]);
        s = __unix_find_socket_byname(net, sunname, len, hash);
        if (s)
                sock_hold(s);
+       spin_unlock(&net->unx.table.locks[hash]);
        spin_unlock(&unix_table_locks[hash]);
        return s;
 }
 
-static struct sock *unix_find_socket_byinode(struct inode *i)
+static struct sock *unix_find_socket_byinode(struct net *net, struct inode *i)
 {
        unsigned int hash = unix_bsd_hash(i);
        struct sock *s;
 
        spin_lock(&unix_table_locks[hash]);
+       spin_lock(&net->unx.table.locks[hash]);
        sk_for_each(s, &unix_socket_table[hash]) {
                struct dentry *dentry = unix_sk(s)->path.dentry;
 
                if (dentry && d_backing_inode(dentry) == i) {
                        sock_hold(s);
+                       spin_unlock(&net->unx.table.locks[hash]);
                        spin_unlock(&unix_table_locks[hash]);
                        return s;
                }
        }
+       spin_unlock(&net->unx.table.locks[hash]);
        spin_unlock(&unix_table_locks[hash]);
        return NULL;
 }
@@ -576,12 +593,12 @@ static void unix_sock_destructor(struct sock *sk)
 static void unix_release_sock(struct sock *sk, int embrion)
 {
        struct unix_sock *u = unix_sk(sk);
-       struct path path;
        struct sock *skpair;
        struct sk_buff *skb;
+       struct path path;
        int state;
 
-       unix_remove_socket(sk);
+       unix_remove_socket(sock_net(sk), sk);
 
        /* Clear state */
        unix_state_lock(sk);
@@ -930,7 +947,7 @@ static struct sock *unix_create1(struct net *net, struct socket *sock, int kern,
        init_waitqueue_head(&u->peer_wait);
        init_waitqueue_func_entry(&u->peer_wake, unix_dgram_peer_wake_relay);
        memset(&u->scm_stat, 0, sizeof(struct scm_stat));
-       unix_insert_unbound_socket(sk);
+       unix_insert_unbound_socket(net, sk);
 
        sock_prot_inuse_add(net, sk->sk_prot, 1);
 
@@ -1015,7 +1032,7 @@ static struct sock *unix_find_bsd(struct net *net, struct sockaddr_un *sunaddr,
        if (!S_ISSOCK(inode->i_mode))
                goto path_put;
 
-       sk = unix_find_socket_byinode(inode);
+       sk = unix_find_socket_byinode(net, inode);
        if (!sk)
                goto path_put;
 
@@ -1074,6 +1091,7 @@ static int unix_autobind(struct sock *sk)
 {
        unsigned int new_hash, old_hash = sk->sk_hash;
        struct unix_sock *u = unix_sk(sk);
+       struct net *net = sock_net(sk);
        struct unix_address *addr;
        u32 lastnum, ordernum;
        int err;
@@ -1102,11 +1120,10 @@ retry:
        sprintf(addr->name->sun_path + 1, "%05x", ordernum);
 
        new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
-       unix_table_double_lock(old_hash, new_hash);
+       unix_table_double_lock(net, old_hash, new_hash);
 
-       if (__unix_find_socket_byname(sock_net(sk), addr->name, addr->len,
-                                     new_hash)) {
-               unix_table_double_unlock(old_hash, new_hash);
+       if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash)) {
+               unix_table_double_unlock(net, old_hash, new_hash);
 
                /* __unix_find_socket_byname() may take long time if many names
                 * are already in use.
@@ -1124,7 +1141,7 @@ retry:
        }
 
        __unix_set_addr_hash(sk, addr, new_hash);
-       unix_table_double_unlock(old_hash, new_hash);
+       unix_table_double_unlock(net, old_hash, new_hash);
        err = 0;
 
 out:   mutex_unlock(&u->bindlock);
@@ -1138,6 +1155,7 @@ static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr,
               (SOCK_INODE(sk->sk_socket)->i_mode & ~current_umask());
        unsigned int new_hash, old_hash = sk->sk_hash;
        struct unix_sock *u = unix_sk(sk);
+       struct net *net = sock_net(sk);
        struct user_namespace *ns; // barf...
        struct unix_address *addr;
        struct dentry *dentry;
@@ -1178,11 +1196,11 @@ static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr,
                goto out_unlock;
 
        new_hash = unix_bsd_hash(d_backing_inode(dentry));
-       unix_table_double_lock(old_hash, new_hash);
+       unix_table_double_lock(net, old_hash, new_hash);
        u->path.mnt = mntget(parent.mnt);
        u->path.dentry = dget(dentry);
        __unix_set_addr_hash(sk, addr, new_hash);
-       unix_table_double_unlock(old_hash, new_hash);
+       unix_table_double_unlock(net, old_hash, new_hash);
        mutex_unlock(&u->bindlock);
        done_path_create(&parent, dentry);
        return 0;
@@ -1205,6 +1223,7 @@ static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr,
 {
        unsigned int new_hash, old_hash = sk->sk_hash;
        struct unix_sock *u = unix_sk(sk);
+       struct net *net = sock_net(sk);
        struct unix_address *addr;
        int err;
 
@@ -1222,19 +1241,18 @@ static int unix_bind_abstract(struct sock *sk, struct sockaddr_un *sunaddr,
        }
 
        new_hash = unix_abstract_hash(addr->name, addr->len, sk->sk_type);
-       unix_table_double_lock(old_hash, new_hash);
+       unix_table_double_lock(net, old_hash, new_hash);
 
-       if (__unix_find_socket_byname(sock_net(sk), addr->name, addr->len,
-                                     new_hash))
+       if (__unix_find_socket_byname(net, addr->name, addr->len, new_hash))
                goto out_spin;
 
        __unix_set_addr_hash(sk, addr, new_hash);
-       unix_table_double_unlock(old_hash, new_hash);
+       unix_table_double_unlock(net, old_hash, new_hash);
        mutex_unlock(&u->bindlock);
        return 0;
 
 out_spin:
-       unix_table_double_unlock(old_hash, new_hash);
+       unix_table_double_unlock(net, old_hash, new_hash);
        err = -EADDRINUSE;
 out_mutex:
        mutex_unlock(&u->bindlock);
@@ -3237,15 +3255,18 @@ static struct sock *unix_from_bucket(struct seq_file *seq, loff_t *pos)
 static struct sock *unix_get_first(struct seq_file *seq, loff_t *pos)
 {
        unsigned long bucket = get_bucket(*pos);
+       struct net *net = seq_file_net(seq);
        struct sock *sk;
 
        while (bucket < UNIX_HASH_SIZE) {
                spin_lock(&unix_table_locks[bucket]);
+               spin_lock(&net->unx.table.locks[bucket]);
 
                sk = unix_from_bucket(seq, pos);
                if (sk)
                        return sk;
 
+               spin_unlock(&net->unx.table.locks[bucket]);
                spin_unlock(&unix_table_locks[bucket]);
 
                *pos = set_bucket_offset(++bucket, 1);
@@ -3258,11 +3279,13 @@ static struct sock *unix_get_next(struct seq_file *seq, struct sock *sk,
                                  loff_t *pos)
 {
        unsigned long bucket = get_bucket(*pos);
+       struct net *net = seq_file_net(seq);
 
        for (sk = sk_next(sk); sk; sk = sk_next(sk))
-               if (sock_net(sk) == seq_file_net(seq))
+               if (sock_net(sk) == net)
                        return sk;
 
+       spin_unlock(&net->unx.table.locks[bucket]);
        spin_unlock(&unix_table_locks[bucket]);
 
        *pos = set_bucket_offset(++bucket, 1);
@@ -3292,8 +3315,10 @@ static void unix_seq_stop(struct seq_file *seq, void *v)
 {
        struct sock *sk = v;
 
-       if (sk)
+       if (sk) {
+               spin_unlock(&seq_file_net(seq)->unx.table.locks[sk->sk_hash]);
                spin_unlock(&unix_table_locks[sk->sk_hash]);
+       }
 }
 
 static int unix_seq_show(struct seq_file *seq, void *v)
@@ -3381,6 +3406,7 @@ static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk)
 
 {
        struct bpf_unix_iter_state *iter = seq->private;
+       struct net *net = seq_file_net(seq);
        unsigned int expected = 1;
        struct sock *sk;
 
@@ -3388,7 +3414,7 @@ static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk)
        iter->batch[iter->end_sk++] = start_sk;
 
        for (sk = sk_next(start_sk); sk; sk = sk_next(sk)) {
-               if (sock_net(sk) != seq_file_net(seq))
+               if (sock_net(sk) != net)
                        continue;
 
                if (iter->end_sk < iter->max_sk) {
@@ -3399,6 +3425,7 @@ static int bpf_iter_unix_hold_batch(struct seq_file *seq, struct sock *start_sk)
                expected++;
        }
 
+       spin_unlock(&net->unx.table.locks[start_sk->sk_hash]);
        spin_unlock(&unix_table_locks[start_sk->sk_hash]);
 
        return expected;

diff --git a/net/unix/diag.c b/net/unix/diag.c
index c5d1cca..7fc3774 100644 (file)
--- a/net/unix/diag.c
+++ b/net/unix/diag.c
@@ -195,9 +195,9 @@ static int sk_diag_dump(struct sock *sk, struct sk_buff *skb, struct unix_diag_r
 
 static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
-       struct unix_diag_req *req;
-       int num, s_num, slot, s_slot;
        struct net *net = sock_net(skb->sk);
+       int num, s_num, slot, s_slot;
+       struct unix_diag_req *req;
 
        req = nlmsg_data(cb->nlh);
 
@@ -209,6 +209,7 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 
                num = 0;
                spin_lock(&unix_table_locks[slot]);
+               spin_lock(&net->unx.table.locks[slot]);
                sk_for_each(sk, &unix_socket_table[slot]) {
                        if (!net_eq(sock_net(sk), net))
                                continue;
@@ -220,12 +221,14 @@ static int unix_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
                                         NETLINK_CB(cb->skb).portid,
                                         cb->nlh->nlmsg_seq,
                                         NLM_F_MULTI) < 0) {
+                               spin_unlock(&net->unx.table.locks[slot]);
                                spin_unlock(&unix_table_locks[slot]);
                                goto done;
                        }
 next:
                        num++;
                }
+               spin_unlock(&net->unx.table.locks[slot]);
                spin_unlock(&unix_table_locks[slot]);
        }
 done:
@@ -235,19 +238,22 @@ done:
        return skb->len;
 }
 
-static struct sock *unix_lookup_by_ino(unsigned int ino)
+static struct sock *unix_lookup_by_ino(struct net *net, unsigned int ino)
 {
        struct sock *sk;
        int i;
 
        for (i = 0; i < UNIX_HASH_SIZE; i++) {
                spin_lock(&unix_table_locks[i]);
+               spin_lock(&net->unx.table.locks[i]);
                sk_for_each(sk, &unix_socket_table[i])
                        if (ino == sock_i_ino(sk)) {
                                sock_hold(sk);
+                               spin_unlock(&net->unx.table.locks[i]);
                                spin_unlock(&unix_table_locks[i]);
                                return sk;
                        }
+               spin_unlock(&net->unx.table.locks[i]);
                spin_unlock(&unix_table_locks[i]);
        }
        return NULL;
@@ -257,16 +263,17 @@ static int unix_diag_get_exact(struct sk_buff *in_skb,
                               const struct nlmsghdr *nlh,
                               struct unix_diag_req *req)
 {
-       int err = -EINVAL;
-       struct sock *sk;
-       struct sk_buff *rep;
-       unsigned int extra_len;
        struct net *net = sock_net(in_skb->sk);
+       unsigned int extra_len;
+       struct sk_buff *rep;
+       struct sock *sk;
+       int err;
 
+       err = -EINVAL;
        if (req->udiag_ino == 0)
                goto out_nosk;
 
-       sk = unix_lookup_by_ino(req->udiag_ino);
+       sk = unix_lookup_by_ino(net, req->udiag_ino);
        err = -ENOENT;
        if (sk == NULL)
                goto out_nosk;