net: make getname() functions return length rather than use int* parameter

Changes since v1:
Added changes in these files:
    drivers/infiniband/hw/usnic/usnic_transport.c
    drivers/staging/lustre/lnet/lnet/lib-socket.c
    drivers/target/iscsi/iscsi_target_login.c
    drivers/vhost/net.c
    fs/dlm/lowcomms.c
    fs/ocfs2/cluster/tcp.c
    security/tomoyo/network.c

Before:
All these functions either return a negative error indicator,
or store length of sockaddr into "int *socklen" parameter
and return zero on success.

"int *socklen" parameter is awkward. For example, if caller does not
care, it still needs to provide on-stack storage for the value
it does not need.

None of the many FOO_getname() functions of various protocols
ever used old value of *socklen. They always just overwrite it.

This change drops this parameter, and makes all these functions, on success,
return length of sockaddr. It's always >= 0 and can be differentiated
from an error.

Tests in callers are changed from "if (err)" to "if (err < 0)", where needed.

rpc_sockname() lost "int buflen" parameter, since its only use was
to be passed to kernel_getsockname() as &buflen and subsequently
not used in any way.

Userspace API is not changed.

    text    data     bss      dec     hex filename
30108430 2633624  873672 33615726 200ef6e vmlinux.before.o
30108109 2633612  873672 33615393 200ee21 vmlinux.o

Signed-off-by: Denys Vlasenko <[email protected]>
CC: David S. Miller <[email protected]>
CC: [email protected]
CC: [email protected]
CC: [email protected]
CC: [email protected]
CC: [email protected]
CC: [email protected]
CC: [email protected]
CC: [email protected]
CC: [email protected]
Signed-off-by: David S. Miller <[email protected]>

net/bluetooth/hci_sock.c

@@ -1340,7 +1340,7 @@ done:
 }
 
 static int hci_sock_getname(struct socket *sock, struct sockaddr *addr,
-			    int *addr_len, int peer)
+			    int peer)
 {
 	struct sockaddr_hci *haddr = (struct sockaddr_hci *)addr;
 	struct sock *sk = sock->sk;
@@ -1360,10 +1360,10 @@ static int hci_sock_getname(struct socket *sock, struct sockaddr *addr,
 		goto done;
 	}
 
-	*addr_len = sizeof(*haddr);
 	haddr->hci_family = AF_BLUETOOTH;
 	haddr->hci_dev    = hdev->id;
 	haddr->hci_channel= hci_pi(sk)->channel;
+	err = sizeof(*haddr);
 
 done:
 	release_sock(sk);

net/bluetooth/l2cap_sock.c

@@ -358,7 +358,7 @@ done:
 }
 
 static int l2cap_sock_getname(struct socket *sock, struct sockaddr *addr,
-			      int *len, int peer)
+			      int peer)
 {
 	struct sockaddr_l2 *la = (struct sockaddr_l2 *) addr;
 	struct sock *sk = sock->sk;
@@ -373,7 +373,6 @@ static int l2cap_sock_getname(struct socket *sock, struct sockaddr *addr,
 
 	memset(la, 0, sizeof(struct sockaddr_l2));
 	addr->sa_family = AF_BLUETOOTH;
-	*len = sizeof(struct sockaddr_l2);
 
 	la->l2_psm = chan->psm;
 
@@ -387,7 +386,7 @@ static int l2cap_sock_getname(struct socket *sock, struct sockaddr *addr,
 		la->l2_bdaddr_type = chan->src_type;
 	}
 
-	return 0;
+	return sizeof(struct sockaddr_l2);
 }
 
 static int l2cap_sock_getsockopt_old(struct socket *sock, int optname,

net/bluetooth/rfcomm/sock.c

@@ -533,7 +533,7 @@ done:
 	return err;
 }
 
-static int rfcomm_sock_getname(struct socket *sock, struct sockaddr *addr, int *len, int peer)
+static int rfcomm_sock_getname(struct socket *sock, struct sockaddr *addr, int peer)
 {
 	struct sockaddr_rc *sa = (struct sockaddr_rc *) addr;
 	struct sock *sk = sock->sk;
@@ -552,8 +552,7 @@ static int rfcomm_sock_getname(struct socket *sock, struct sockaddr *addr, int *
 	else
 		bacpy(&sa->rc_bdaddr, &rfcomm_pi(sk)->src);
 
-	*len = sizeof(struct sockaddr_rc);
-	return 0;
+	return sizeof(struct sockaddr_rc);
 }
 
 static int rfcomm_sock_sendmsg(struct socket *sock, struct msghdr *msg,

net/bluetooth/sco.c

@@ -680,7 +680,7 @@ done:
 }
 
 static int sco_sock_getname(struct socket *sock, struct sockaddr *addr,
-			    int *len, int peer)
+			    int peer)
 {
 	struct sockaddr_sco *sa = (struct sockaddr_sco *) addr;
 	struct sock *sk = sock->sk;
@@ -688,14 +688,13 @@ static int sco_sock_getname(struct socket *sock, struct sockaddr *addr,
 	BT_DBG("sock %p, sk %p", sock, sk);
 
 	addr->sa_family = AF_BLUETOOTH;
-	*len = sizeof(struct sockaddr_sco);
 
 	if (peer)
 		bacpy(&sa->sco_bdaddr, &sco_pi(sk)->dst);
 	else
 		bacpy(&sa->sco_bdaddr, &sco_pi(sk)->src);
 
-	return 0;
+	return sizeof(struct sockaddr_sco);
 }
 
 static int sco_sock_sendmsg(struct socket *sock, struct msghdr *msg,