net/smc: Use correct buffer sizes when switching between TCP and SMC

Tuning of the effective buffer size through setsockopts was working for
SMC traffic only but not for TCP fall-back connections even before
commit 0227f058aa29 ("net/smc: Unbind r/w buffer size from clcsock and
make them tunable"). That change made it apparent that TCP fall-back
connections would use net.smc.[rw]mem as buffer size instead of
net.ipv4_tcp_[rw]mem.

Amend the code that copies attributes between the (TCP) clcsock and the
SMC socket and adjust buffer sizes appropriately:
- Copy over sk_userlocks so that both sockets agree on whether tuning
  via setsockopt is active.
- When falling back to TCP use sk_sndbuf or sk_rcvbuf as specified with
  setsockopt. Otherwise, use the sysctl value for TCP/IPv4.
- Likewise, use either values from setsockopt or from sysctl for SMC
  (duplicated) on successful SMC connect.

In smc_tcp_listen_work() drop the explicit copy of buffer sizes as that
is taken care of by the attribute copy.

Fixes: 0227f058aa29 ("net/smc: Unbind r/w buffer size from clcsock and make them tunable")
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 5b878e523abf224f7c0f948f9daaada90d6ec969..f5834af5fad535c420381827548cecdf0d03b0d5 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -436,13 +436,60 @@ out:
        return rc;
 }
 
+/* copy only relevant settings and flags of SOL_SOCKET level from smc to
+ * clc socket (since smc is not called for these options from net/core)
+ */
+
+#define SK_FLAGS_SMC_TO_CLC ((1UL << SOCK_URGINLINE) | \
+                            (1UL << SOCK_KEEPOPEN) | \
+                            (1UL << SOCK_LINGER) | \
+                            (1UL << SOCK_BROADCAST) | \
+                            (1UL << SOCK_TIMESTAMP) | \
+                            (1UL << SOCK_DBG) | \
+                            (1UL << SOCK_RCVTSTAMP) | \
+                            (1UL << SOCK_RCVTSTAMPNS) | \
+                            (1UL << SOCK_LOCALROUTE) | \
+                            (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE) | \
+                            (1UL << SOCK_RXQ_OVFL) | \
+                            (1UL << SOCK_WIFI_STATUS) | \
+                            (1UL << SOCK_NOFCS) | \
+                            (1UL << SOCK_FILTER_LOCKED) | \
+                            (1UL << SOCK_TSTAMP_NEW))
+
+/* if set, use value set by setsockopt() - else use IPv4 or SMC sysctl value */
+static void smc_adjust_sock_bufsizes(struct sock *nsk, struct sock *osk,
+                                    unsigned long mask)
+{
+       struct net *nnet = sock_net(nsk);
+
+       nsk->sk_userlocks = osk->sk_userlocks;
+       if (osk->sk_userlocks & SOCK_SNDBUF_LOCK) {
+               nsk->sk_sndbuf = osk->sk_sndbuf;
+       } else {
+               if (mask == SK_FLAGS_SMC_TO_CLC)
+                       WRITE_ONCE(nsk->sk_sndbuf,
+                                  READ_ONCE(nnet->ipv4.sysctl_tcp_wmem[1]));
+               else
+                       WRITE_ONCE(nsk->sk_sndbuf,
+                                  2 * READ_ONCE(nnet->smc.sysctl_wmem));
+       }
+       if (osk->sk_userlocks & SOCK_RCVBUF_LOCK) {
+               nsk->sk_rcvbuf = osk->sk_rcvbuf;
+       } else {
+               if (mask == SK_FLAGS_SMC_TO_CLC)
+                       WRITE_ONCE(nsk->sk_rcvbuf,
+                                  READ_ONCE(nnet->ipv4.sysctl_tcp_rmem[1]));
+               else
+                       WRITE_ONCE(nsk->sk_rcvbuf,
+                                  2 * READ_ONCE(nnet->smc.sysctl_rmem));
+       }
+}
+
 static void smc_copy_sock_settings(struct sock *nsk, struct sock *osk,
                                   unsigned long mask)
 {
        /* options we don't get control via setsockopt for */
        nsk->sk_type = osk->sk_type;
-       nsk->sk_sndbuf = osk->sk_sndbuf;
-       nsk->sk_rcvbuf = osk->sk_rcvbuf;
        nsk->sk_sndtimeo = osk->sk_sndtimeo;
        nsk->sk_rcvtimeo = osk->sk_rcvtimeo;
        nsk->sk_mark = READ_ONCE(osk->sk_mark);
@@ -453,26 +500,10 @@ static void smc_copy_sock_settings(struct sock *nsk, struct sock *osk,
 
        nsk->sk_flags &= ~mask;
        nsk->sk_flags |= osk->sk_flags & mask;
+
+       smc_adjust_sock_bufsizes(nsk, osk, mask);
 }
 
-#define SK_FLAGS_SMC_TO_CLC ((1UL << SOCK_URGINLINE) | \
-                            (1UL << SOCK_KEEPOPEN) | \
-                            (1UL << SOCK_LINGER) | \
-                            (1UL << SOCK_BROADCAST) | \
-                            (1UL << SOCK_TIMESTAMP) | \
-                            (1UL << SOCK_DBG) | \
-                            (1UL << SOCK_RCVTSTAMP) | \
-                            (1UL << SOCK_RCVTSTAMPNS) | \
-                            (1UL << SOCK_LOCALROUTE) | \
-                            (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE) | \
-                            (1UL << SOCK_RXQ_OVFL) | \
-                            (1UL << SOCK_WIFI_STATUS) | \
-                            (1UL << SOCK_NOFCS) | \
-                            (1UL << SOCK_FILTER_LOCKED) | \
-                            (1UL << SOCK_TSTAMP_NEW))
-/* copy only relevant settings and flags of SOL_SOCKET level from smc to
- * clc socket (since smc is not called for these options from net/core)
- */
 static void smc_copy_sock_settings_to_clc(struct smc_sock *smc)
 {
        smc_copy_sock_settings(smc->clcsock->sk, &smc->sk, SK_FLAGS_SMC_TO_CLC);
@@ -2479,8 +2510,6 @@ static void smc_tcp_listen_work(struct work_struct *work)
                sock_hold(lsk); /* sock_put in smc_listen_work */
                INIT_WORK(&new_smc->smc_listen_work, smc_listen_work);
                smc_copy_sock_settings_to_smc(new_smc);
-               new_smc->sk.sk_sndbuf = lsmc->sk.sk_sndbuf;
-               new_smc->sk.sk_rcvbuf = lsmc->sk.sk_rcvbuf;
                sock_hold(&new_smc->sk); /* sock_put in passive closing */
                if (!queue_work(smc_hs_wq, &new_smc->smc_listen_work))
                        sock_put(&new_smc->sk);