net: use unrcu_pointer() helper

Toke mentioned unrcu_pointer() existence, allowing
to remove some of the ugly casts we have when using
xchg() for rcu protected pointers.

Also make inet_rcv_compat const.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20240604111603.45871-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/include/net/sock.h b/include/net/sock.h
index 953c8dc4e259e84b927cc77edc0e55cdde654e94..b30ea0c342a652b371c6ad45ab6e5f835ba31aeb 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2095,7 +2095,7 @@ sk_dst_set(struct sock *sk, struct dst_entry *dst)
 
        sk_tx_queue_clear(sk);
        WRITE_ONCE(sk->sk_dst_pending_confirm, 0);
-       old_dst = xchg((__force struct dst_entry **)&sk->sk_dst_cache, dst);
+       old_dst = unrcu_pointer(xchg(&sk->sk_dst_cache, RCU_INITIALIZER(dst)));
        dst_release(old_dst);
 }
 

diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index fae9c4694186eaaac3295f32c7cb2f6b7e5e0906..412816076b8bc5543ed1eb32838438d1966cd473 100644 (file)
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -206,7 +206,7 @@ void gen_kill_estimator(struct net_rate_estimator __rcu **rate_est)
 {
        struct net_rate_estimator *est;
 
-       est = xchg((__force struct net_rate_estimator **)rate_est, NULL);
+       est = unrcu_pointer(xchg(rate_est, NULL));
        if (est) {
                timer_shutdown_sync(&est->timer);
                kfree_rcu(est, rcu);

diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 6541228380252d597821b084df34176bff4ada83..a08eed9b9142e38d5f4a6a16c139b37d1a84cad1 100644 (file)
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -18,7 +18,7 @@
 
 static const struct sock_diag_handler __rcu *sock_diag_handlers[AF_MAX];
 
-static struct sock_diag_inet_compat __rcu *inet_rcv_compat;
+static const struct sock_diag_inet_compat __rcu *inet_rcv_compat;
 
 static struct workqueue_struct *broadcast_wq;
 
@@ -187,8 +187,7 @@ void sock_diag_broadcast_destroy(struct sock *sk)
 
 void sock_diag_register_inet_compat(const struct sock_diag_inet_compat *ptr)
 {
-       xchg((__force const struct sock_diag_inet_compat **)&inet_rcv_compat,
-            ptr);
+       xchg(&inet_rcv_compat, RCU_INITIALIZER(ptr));
 }
 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
 
@@ -196,8 +195,7 @@ void sock_diag_unregister_inet_compat(const struct sock_diag_inet_compat *ptr)
 {
        const struct sock_diag_inet_compat *old;
 
-       old = xchg((__force const struct sock_diag_inet_compat **)&inet_rcv_compat,
-                  NULL);
+       old = unrcu_pointer(xchg(&inet_rcv_compat, NULL));
        WARN_ON_ONCE(old != ptr);
 }
 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index dd6d4601505806c79f008db69a98c0aff20eb516..3a95c0f13ce33a29d0289373255a9c8302d63edb 100644 (file)
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1953,7 +1953,7 @@ int cipso_v4_req_setattr(struct request_sock *req,
        buf = NULL;
 
        req_inet = inet_rsk(req);
-       opt = xchg((__force struct ip_options_rcu **)&req_inet->ireq_opt, opt);
+       opt = unrcu_pointer(xchg(&req_inet->ireq_opt, RCU_INITIALIZER(opt)));
        if (opt)
                kfree_rcu(opt, rcu);
 

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index fa43aaacd92bcf78ab542d0d5f267b4cbdfacf26..f727bc8d82a6d28f97143f1f235a67f8b130d8d4 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3081,7 +3081,7 @@ int tcp_disconnect(struct sock *sk, int flags)
        icsk->icsk_ack.rcv_mss = TCP_MIN_MSS;
        memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
        __sk_dst_reset(sk);
-       dst_release(xchg((__force struct dst_entry **)&sk->sk_rx_dst, NULL));
+       dst_release(unrcu_pointer(xchg(&sk->sk_rx_dst, NULL)));
        tcp_saved_syn_free(tp);
        tp->compressed_ack = 0;
        tp->segs_in = 0;

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 8ed54e7334a9c646dfbbc6dc41b9ef11b925de0a..0f523cbfe329efeaee2ef206b0779e9911ef22cd 100644 (file)
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -49,7 +49,7 @@ void tcp_fastopen_ctx_destroy(struct net *net)
 {
        struct tcp_fastopen_context *ctxt;
 
-       ctxt = xchg((__force struct tcp_fastopen_context **)&net->ipv4.tcp_fastopen_ctx, NULL);
+       ctxt = unrcu_pointer(xchg(&net->ipv4.tcp_fastopen_ctx, NULL));
 
        if (ctxt)
                call_rcu(&ctxt->rcu, tcp_fastopen_ctx_free);
@@ -80,9 +80,10 @@ int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
 
        if (sk) {
                q = &inet_csk(sk)->icsk_accept_queue.fastopenq;
-               octx = xchg((__force struct tcp_fastopen_context **)&q->ctx, ctx);
+               octx = unrcu_pointer(xchg(&q->ctx, RCU_INITIALIZER(ctx)));
        } else {
-               octx = xchg((__force struct tcp_fastopen_context **)&net->ipv4.tcp_fastopen_ctx, ctx);
+               octx = unrcu_pointer(xchg(&net->ipv4.tcp_fastopen_ctx,
+                                         RCU_INITIALIZER(ctx)));
        }
 
        if (octx)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 189c9113fe9a180cc2788632892cbd12a829a500..c9ca6d285347b8c3032e2a779b39aa426bd6ee4a 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2230,7 +2230,7 @@ bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
        struct dst_entry *old;
 
        if (dst_hold_safe(dst)) {
-               old = xchg((__force struct dst_entry **)&sk->sk_rx_dst, dst);
+               old = unrcu_pointer(xchg(&sk->sk_rx_dst, RCU_INITIALIZER(dst)));
                dst_release(old);
                return old != dst;
        }

diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 8041dc181bd42e5e1af2d9e9fe6af50057e5b58f..e03fb9a1dbeb46081b50e016064bdf296002e092 100644 (file)
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -509,7 +509,7 @@ void inet6_cleanup_sock(struct sock *sk)
 
        /* Free tx options */
 
-       opt = xchg((__force struct ipv6_txoptions **)&np->opt, NULL);
+       opt = unrcu_pointer(xchg(&np->opt, NULL));
        if (opt) {
                atomic_sub(opt->tot_len, &sk->sk_omem_alloc);
                txopt_put(opt);

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 31d77885bcae3e3843b6d486cfc21cdbe709bcf0..15f9abe506562eaa6a9c29c746be97ca7a2288d0 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -984,7 +984,7 @@ static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
                if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) {
                        struct fib6_info *from;
 
-                       from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
+                       from = unrcu_pointer(xchg(&pcpu_rt->from, NULL));
                        fib6_info_release(from);
                }
        }

diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index d4c28ec1bc517b33498b08b59bcda5fe960f652f..cd342d5015c6fb36bd03d4f3fcae4a3995ff6097 100644 (file)
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -111,8 +111,7 @@ struct ipv6_txoptions *ipv6_update_options(struct sock *sk,
                        icsk->icsk_sync_mss(sk, icsk->icsk_pmtu_cookie);
                }
        }
-       opt = xchg((__force struct ipv6_txoptions **)&inet6_sk(sk)->opt,
-                  opt);
+       opt = unrcu_pointer(xchg(&inet6_sk(sk)->opt, RCU_INITIALIZER(opt)));
        sk_dst_reset(sk);
 
        return opt;

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 12f647d0fec0f45415de32b6789672c9b772a8dd..ae6fbdf8995df821d1f9da8a6b9832017a436a73 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -368,7 +368,7 @@ static void ip6_dst_destroy(struct dst_entry *dst)
                in6_dev_put(idev);
        }
 
-       from = xchg((__force struct fib6_info **)&rt->from, NULL);
+       from = unrcu_pointer(xchg(&rt->from, NULL));
        fib6_info_release(from);
 }
 
@@ -1437,7 +1437,7 @@ static struct rt6_info *rt6_make_pcpu_route(struct net *net,
        if (res->f6i->fib6_destroying) {
                struct fib6_info *from;
 
-               from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
+               from = unrcu_pointer(xchg(&pcpu_rt->from, NULL));
                fib6_info_release(from);
        }
 
@@ -1466,7 +1466,7 @@ static void rt6_remove_exception(struct rt6_exception_bucket *bucket,
        /* purge completely the exception to allow releasing the held resources:
         * some [sk] cache may keep the dst around for unlimited time
         */
-       from = xchg((__force struct fib6_info **)&rt6_ex->rt6i->from, NULL);
+       from = unrcu_pointer(xchg(&rt6_ex->rt6i->from, NULL));
        fib6_info_release(from);
        dst_dev_put(&rt6_ex->rt6i->dst);
 

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 9ee622fb1160fe5de8df9a5fca0c9a412e40e31a..7458b3154426279123a8b178fe40f05ce657b5c2 100644 (file)
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -62,7 +62,7 @@ static void tcf_set_action_cookie(struct tc_cookie __rcu **old_cookie,
 {
        struct tc_cookie *old;
 
-       old = xchg((__force struct tc_cookie **)old_cookie, new_cookie);
+       old = unrcu_pointer(xchg(old_cookie, RCU_INITIALIZER(new_cookie)));
        if (old)
                call_rcu(&old->rcu, tcf_free_cookie_rcu);
 }