From: Christoph Hellwig <hch@lst.de>
Date: Thu, 28 May 2020 07:12:09 +0200
Subject: net: add sock_set_reuseaddr
Patch-mainline: v5.8-rc1
Git-commit: b58f0e8f38c0a44afa59601a115bd231f23471e1
References: bsc#1177028

Add a helper to directly set the SO_REUSEADDR sockopt from kernel space
without going through a fake uaccess.

For this the iscsi target now has to formally depend on inet to avoid
a mostly theoretical compile failure.  For actual operation it already
did depend on having ipv4 or ipv6 support.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Gary Lin <glin@suse.com>
---
 drivers/infiniband/sw/siw/siw_cm.c        |   18 +++++-------------
 drivers/nvme/target/tcp.c                 |    8 +-------
 drivers/target/iscsi/Kconfig              |    2 +-
 drivers/target/iscsi/iscsi_target_login.c |    9 +--------
 fs/dlm/lowcomms.c                         |    6 +-----
 include/net/sock.h                        |    2 ++
 net/core/sock.c                           |    8 ++++++++
 7 files changed, 19 insertions(+), 34 deletions(-)

--- a/drivers/infiniband/sw/siw/siw_cm.c
+++ b/drivers/infiniband/sw/siw/siw_cm.c
@@ -1312,17 +1312,14 @@ static void siw_cm_llp_state_change(stru
 static int kernel_bindconnect(struct socket *s, struct sockaddr *laddr,
 			      struct sockaddr *raddr)
 {
-	int rv, flags = 0, s_val = 1;
+	int rv, flags = 0;
 	size_t size = laddr->sa_family == AF_INET ?
 		sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6);
 
 	/*
 	 * Make address available again asap.
 	 */
-	rv = kernel_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&s_val,
-			       sizeof(s_val));
-	if (rv < 0)
-		return rv;
+	sock_set_reuseaddr(s->sk);
 
 	rv = s->ops->bind(s, laddr, size);
 	if (rv < 0)
@@ -1781,7 +1778,7 @@ int siw_create_listen(struct iw_cm_id *i
 	struct siw_cep *cep = NULL;
 	struct siw_device *sdev = to_siw_dev(id->device);
 	int addr_family = id->local_addr.ss_family;
-	int rv = 0, s_val;
+	int rv = 0;
 
 	if (addr_family != AF_INET && addr_family != AF_INET6)
 		return -EAFNOSUPPORT;
@@ -1793,13 +1790,8 @@ int siw_create_listen(struct iw_cm_id *i
 	/*
 	 * Allow binding local port when still in TIME_WAIT from last close.
 	 */
-	s_val = 1;
-	rv = kernel_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char *)&s_val,
-			       sizeof(s_val));
-	if (rv) {
-		siw_dbg(id->device, "setsockopt error: %d\n", rv);
-		goto error;
-	}
+	sock_set_reuseaddr(s->sk);
+
 	if (addr_family == AF_INET) {
 		struct sockaddr_in *laddr = &to_sockaddr_in(id->local_addr);
 
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1639,6 +1639,7 @@ static int nvmet_tcp_add_port(struct nvm
 	port->sock->sk->sk_user_data = port;
 	port->data_ready = port->sock->sk->sk_data_ready;
 	port->sock->sk->sk_data_ready = nvmet_tcp_listen_data_ready;
+	sock_set_reuseaddr(port->sock->sk);
 
 	opt = 1;
 	ret = kernel_setsockopt(port->sock, IPPROTO_TCP,
@@ -1648,13 +1649,6 @@ static int nvmet_tcp_add_port(struct nvm
 		goto err_sock;
 	}
 
-	ret = kernel_setsockopt(port->sock, SOL_SOCKET, SO_REUSEADDR,
-			(char *)&opt, sizeof(opt));
-	if (ret) {
-		pr_err("failed to set SO_REUSEADDR sock opt %d\n", ret);
-		goto err_sock;
-	}
-
 	if (so_priority > 0) {
 		ret = kernel_setsockopt(port->sock, SOL_SOCKET, SO_PRIORITY,
 				(char *)&so_priority, sizeof(so_priority));
--- a/drivers/target/iscsi/Kconfig
+++ b/drivers/target/iscsi/Kconfig
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 config ISCSI_TARGET
 	tristate "Linux-iSCSI.org iSCSI Target Mode Stack"
-	depends on NET
+	depends on INET
 	select CRYPTO
 	select CRYPTO_CRC32C
 	select CRYPTO_CRC32C_INTEL if X86
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -909,14 +909,7 @@ int iscsit_setup_np(
 		}
 	}
 
-	/* FIXME: Someone please explain why this is endian-safe */
-	ret = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
-			(char *)&opt, sizeof(opt));
-	if (ret < 0) {
-		pr_err("kernel_setsockopt() for SO_REUSEADDR"
-			" failed\n");
-		goto fail;
-	}
+	sock_set_reuseaddr(sock->sk);
 
 	ret = kernel_setsockopt(sock, IPPROTO_IP, IP_FREEBIND,
 			(char *)&opt, sizeof(opt));
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -1244,12 +1244,8 @@ static struct socket *tcp_create_listen_
 	kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
 			  sizeof(one));
 
-	result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
-				   (char *)&one, sizeof(one));
+	sock_set_reuseaddr(sock->sk);
 
-	if (result < 0) {
-		log_print("Failed to set SO_REUSEADDR on socket: %d", result);
-	}
 	write_lock_bh(&sock->sk->sk_callback_lock);
 	sock->sk->sk_user_data = con;
 	save_listen_callbacks(sock);
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2676,4 +2676,6 @@ static inline bool sk_dev_equal_l3scope(
 
 void sock_def_readable(struct sock *sk);
 
+void sock_set_reuseaddr(struct sock *sk);
+
 #endif	/* _SOCK_H */
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -712,6 +712,14 @@ bool sk_mc_loop(struct sock *sk)
 }
 EXPORT_SYMBOL(sk_mc_loop);
 
+void sock_set_reuseaddr(struct sock *sk)
+{
+	lock_sock(sk);
+	sk->sk_reuse = SK_CAN_REUSE;
+	release_sock(sk);
+}
+EXPORT_SYMBOL(sock_set_reuseaddr);
+
 /*
  *	This is meant for all protocols to use and covers goings on
  *	at the socket level. Everything here is generic.