[PATCH net-next] mptcp: change mptcp_established_options() to return opt

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* [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
@ 2026-06-01  9:18 Eric Dumazet
  2026-06-01 10:17 ` Matthieu Baerts
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Eric Dumazet @ 2026-06-01  9:18 UTC (permalink / raw)
  To: David S . Miller, Jakub Kicinski, Paolo Abeni
  Cc: Simon Horman, Neal Cardwell, Kuniyuki Iwashima, Matthieu Baerts,
	Mat Martineau, Geliang Tang, netdev, eric.dumazet, Eric Dumazet

Instead of passing opt_size address to mptcp_established_options(),
change this function to return it by value.

This removes the need for an expensive stack canary in
tcp_established_options() when CONFIG_STACKPROTECTOR_STRONG=y.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-92 (-92)
Function                                     old     new   delta
tcp_options_write.isra                      1423    1407     -16
mptcp_established_options                   2746    2720     -26
tcp_established_options                      553     503     -50
Total: Before=22110750, After=22110658, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/mptcp.h   | 18 +++++++++---------
 net/ipv4/tcp_output.c |  7 ++++---
 net/mptcp/options.c   | 31 ++++++++++++++++---------------
 3 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index f7263fe2a2e40b507257c3720cc2d78d37357d6d..cd4639beceaa53c573135ddaeb7528a80b4ca824 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -149,9 +149,9 @@ bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
 		       unsigned int *size, struct mptcp_out_options *opts);
 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
 			  struct mptcp_out_options *opts);
-bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
-			       unsigned int *size, unsigned int remaining,
-			       struct mptcp_out_options *opts);
+int mptcp_established_options(struct sock *sk, struct sk_buff *skb,
+			      unsigned int remaining,
+			      struct mptcp_out_options *opts);
 bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
 
 void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
@@ -266,13 +266,13 @@ static inline bool mptcp_synack_options(const struct request_sock *req,
 	return false;
 }
 
-static inline bool mptcp_established_options(struct sock *sk,
-					     struct sk_buff *skb,
-					     unsigned int *size,
-					     unsigned int remaining,
-					     struct mptcp_out_options *opts)
+static inline int mptcp_established_options(struct sock *sk,
+					    struct sk_buff *skb,
+					    unsigned int *size,
+					    unsigned int remaining,
+					    struct mptcp_out_options *opts)
 {
-	return false;
+	return -1;
 }
 
 static inline bool mptcp_incoming_options(struct sock *sk,
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index ef0c10cd31c71ff585a937fde37f2b08b1214b5a..31b459ecbe8307a8660623038fea6fa7b0860f7f 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1181,10 +1181,11 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
 	 */
 	if (sk_is_mptcp(sk)) {
 		unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
-		unsigned int opt_size = 0;
+		int opt_size;
 
-		if (mptcp_established_options(sk, skb, &opt_size, remaining,
-					      &opts->mptcp)) {
+		opt_size = mptcp_established_options(sk, skb, remaining,
+						     &opts->mptcp);
+		if (opt_size >= 0) {
 			opts->options |= OPTION_MPTCP;
 			size += opt_size;
 		}
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 8a1c5698983cff3082d68290626dd8f1e044527f..53528301394d70072dde6614feca6128ea949436 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -836,13 +836,14 @@ static bool mptcp_established_options_mp_fail(struct sock *sk,
 	return true;
 }
 
-bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
-			       unsigned int *size, unsigned int remaining,
-			       struct mptcp_out_options *opts)
+int mptcp_established_options(struct sock *sk, struct sk_buff *skb,
+			      unsigned int remaining,
+			      struct mptcp_out_options *opts)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
 	unsigned int opt_size = 0;
+	int total_size = 0;
 	bool snd_data_fin;
 	bool ret = false;
 
@@ -852,20 +853,20 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 	 * option space.
 	 */
 	if (unlikely(__mptcp_check_fallback(msk) && !mptcp_check_infinite_map(skb)))
-		return true;
+		return 0;
 
 	if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) {
 		if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) ||
 		    mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) {
-			*size += opt_size;
+			total_size += opt_size;
 			remaining -= opt_size;
 		}
 		/* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */
 		if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
-			*size += opt_size;
+			total_size += opt_size;
 			remaining -= opt_size;
 		}
-		return true;
+		return total_size;
 	}
 
 	snd_data_fin = mptcp_data_fin_enabled(msk);
@@ -877,9 +878,9 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 		ret = true;
 		if (mptcp_established_options_mp_fail(sk, &mp_fail_size,
 						      remaining - opt_size, opts)) {
-			*size += opt_size + mp_fail_size;
+			total_size += opt_size + mp_fail_size;
 			remaining -= opt_size - mp_fail_size;
-			return true;
+			return total_size;
 		}
 	}
 
@@ -887,27 +888,27 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 	 * TCP option space would be fatal
 	 */
 	if (WARN_ON_ONCE(opt_size > remaining))
-		return false;
+		return -1;
 
-	*size += opt_size;
+	total_size += opt_size;
 	remaining -= opt_size;
 	if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) {
-		*size += opt_size;
+		total_size += opt_size;
 		remaining -= opt_size;
 		ret = true;
 	} else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) {
-		*size += opt_size;
+		total_size += opt_size;
 		remaining -= opt_size;
 		ret = true;
 	}
 
 	if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) {
-		*size += opt_size;
+		total_size += opt_size;
 		remaining -= opt_size;
 		ret = true;
 	}
 
-	return ret;
+	return ret ? total_size : -1;
 }
 
 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
-- 
2.54.0.1013.g208068f2d8-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
  2026-06-01  9:18 [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size Eric Dumazet
@ 2026-06-01 10:17 ` Matthieu Baerts
  2026-06-01 17:52 ` kernel test robot
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Matthieu Baerts @ 2026-06-01 10:17 UTC (permalink / raw)
  To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
  Cc: Simon Horman, Neal Cardwell, Kuniyuki Iwashima, Mat Martineau,
	Geliang Tang, netdev, eric.dumazet

Hi Eric,

On 01/06/2026 19:18, Eric Dumazet wrote:
> Instead of passing opt_size address to mptcp_established_options(),
> change this function to return it by value.
> 
> This removes the need for an expensive stack canary in
> tcp_established_options() when CONFIG_STACKPROTECTOR_STRONG=y.
> 
> $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
> add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-92 (-92)
> Function                                     old     new   delta
> tcp_options_write.isra                      1423    1407     -16
> mptcp_established_options                   2746    2720     -26
> tcp_established_options                      553     503     -50
> Total: Before=22110750, After=22110658, chg -0.00%

Thank you for looking at that!
> diff --git a/include/net/mptcp.h b/include/net/mptcp.h
> index f7263fe2a2e40b507257c3720cc2d78d37357d6d..cd4639beceaa53c573135ddaeb7528a80b4ca824 100644
> --- a/include/net/mptcp.h
> +++ b/include/net/mptcp.h
> @@ -149,9 +149,9 @@ bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
>  		       unsigned int *size, struct mptcp_out_options *opts);
>  bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
>  			  struct mptcp_out_options *opts);
> -bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
> -			       unsigned int *size, unsigned int remaining,
> -			       struct mptcp_out_options *opts);
> +int mptcp_established_options(struct sock *sk, struct sk_buff *skb,
> +			      unsigned int remaining,
> +			      struct mptcp_out_options *opts);
>  bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
>  
>  void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
> @@ -266,13 +266,13 @@ static inline bool mptcp_synack_options(const struct request_sock *req,
>  	return false;
>  }
>  
> -static inline bool mptcp_established_options(struct sock *sk,
> -					     struct sk_buff *skb,
> -					     unsigned int *size,
> -					     unsigned int remaining,
> -					     struct mptcp_out_options *opts)
> +static inline int mptcp_established_options(struct sock *sk,
> +					    struct sk_buff *skb,
> +					    unsigned int *size,

I guess this line should be removed: that's the version when MPTCP is
not enabled.

Apart from that, the rest looks good to me!

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
  2026-06-01  9:18 [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size Eric Dumazet
  2026-06-01 10:17 ` Matthieu Baerts
@ 2026-06-01 17:52 ` kernel test robot
  2026-06-02  2:09 ` kernel test robot
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2026-06-01 17:52 UTC (permalink / raw)
  To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
  Cc: llvm, oe-kbuild-all, Simon Horman, Neal Cardwell,
	Kuniyuki Iwashima, Matthieu Baerts, Mat Martineau, Geliang Tang,
	netdev, eric.dumazet, Eric Dumazet

Hi Eric,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/mptcp-change-mptcp_established_options-to-return-opt_size/20260601-174435
base:   net-next/main
patch link:    https://lore.kernel.org/r/20260601091816.444738-1-edumazet%40google.com
patch subject: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20260601/202606011921.XxnF0IB7-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260601/202606011921.XxnF0IB7-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202606011921.XxnF0IB7-lkp@intel.com/

All errors (new ones prefixed by >>):

>> net/ipv4/tcp_output.c:1187:24: error: too few arguments to function call, expected 5, have 4
    1186 |                 opt_size = mptcp_established_options(sk, skb, remaining,
         |                            ~~~~~~~~~~~~~~~~~~~~~~~~~
    1187 |                                                      &opts->mptcp);
         |                                                                  ^
   include/net/mptcp.h:269:19: note: 'mptcp_established_options' declared here
     269 | static inline int mptcp_established_options(struct sock *sk,
         |                   ^                         ~~~~~~~~~~~~~~~~
     270 |                                             struct sk_buff *skb,
         |                                             ~~~~~~~~~~~~~~~~~~~~
     271 |                                             unsigned int *size,
         |                                             ~~~~~~~~~~~~~~~~~~~
     272 |                                             unsigned int remaining,
         |                                             ~~~~~~~~~~~~~~~~~~~~~~~
     273 |                                             struct mptcp_out_options *opts)
         |                                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   1 error generated.


vim +1187 net/ipv4/tcp_output.c

  1145	
  1146	/* Compute TCP options for ESTABLISHED sockets. This is not the
  1147	 * final wire format yet.
  1148	 */
  1149	static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb,
  1150						struct tcp_out_options *opts,
  1151						struct tcp_key *key)
  1152	{
  1153		struct tcp_sock *tp = tcp_sk(sk);
  1154		unsigned int size = 0;
  1155		unsigned int eff_sacks;
  1156	
  1157		opts->options = 0;
  1158	
  1159		/* Better than switch (key.type) as it has static branches */
  1160		if (tcp_key_is_md5(key)) {
  1161			opts->options |= OPTION_MD5;
  1162			size += TCPOLEN_MD5SIG_ALIGNED;
  1163		} else if (tcp_key_is_ao(key)) {
  1164			opts->options |= OPTION_AO;
  1165			size += tcp_ao_len_aligned(key->ao_key);
  1166		}
  1167	
  1168		if (likely(tp->rx_opt.tstamp_ok)) {
  1169			opts->options |= OPTION_TS;
  1170			opts->tsval = skb ? tcp_skb_timestamp_ts(tp->tcp_usec_ts, skb) +
  1171					tp->tsoffset : 0;
  1172			opts->tsecr = tp->rx_opt.ts_recent;
  1173			size += TCPOLEN_TSTAMP_ALIGNED;
  1174		}
  1175	
  1176		/* MPTCP options have precedence over SACK for the limited TCP
  1177		 * option space because a MPTCP connection would be forced to
  1178		 * fall back to regular TCP if a required multipath option is
  1179		 * missing. SACK still gets a chance to use whatever space is
  1180		 * left.
  1181		 */
  1182		if (sk_is_mptcp(sk)) {
  1183			unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1184			int opt_size;
  1185	
  1186			opt_size = mptcp_established_options(sk, skb, remaining,
> 1187							     &opts->mptcp);
  1188			if (opt_size >= 0) {
  1189				opts->options |= OPTION_MPTCP;
  1190				size += opt_size;
  1191			}
  1192		}
  1193	
  1194		eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;
  1195		if (unlikely(eff_sacks)) {
  1196			const unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1197			if (likely(remaining >= TCPOLEN_SACK_BASE_ALIGNED +
  1198						TCPOLEN_SACK_PERBLOCK)) {
  1199				opts->num_sack_blocks =
  1200					min_t(unsigned int, eff_sacks,
  1201					      (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
  1202					      TCPOLEN_SACK_PERBLOCK);
  1203	
  1204				size += TCPOLEN_SACK_BASE_ALIGNED +
  1205					opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
  1206			} else {
  1207				opts->num_sack_blocks = 0;
  1208			}
  1209		} else {
  1210			opts->num_sack_blocks = 0;
  1211		}
  1212	
  1213		if (tcp_ecn_mode_accecn(tp)) {
  1214			int ecn_opt = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option);
  1215	
  1216			if (ecn_opt && tp->saw_accecn_opt &&
  1217			    (ecn_opt >= TCP_ACCECN_OPTION_PERSIST ||
  1218			     !tcp_accecn_opt_fail_send(tp)) &&
  1219			    (ecn_opt >= TCP_ACCECN_OPTION_FULL || tp->accecn_opt_demand ||
  1220			     tcp_accecn_option_beacon_check(sk))) {
  1221				opts->use_synack_ecn_bytes = 0;
  1222				size += tcp_options_fit_accecn(opts, tp->accecn_minlen,
  1223							       MAX_TCP_OPTION_SPACE - size);
  1224			}
  1225		}
  1226	
  1227		if (unlikely(BPF_SOCK_OPS_TEST_FLAG(tp,
  1228						    BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG))) {
  1229			unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1230	
  1231			bpf_skops_hdr_opt_len(sk, skb, NULL, NULL, 0, opts, &remaining);
  1232	
  1233			size = MAX_TCP_OPTION_SPACE - remaining;
  1234		}
  1235	
  1236		return size;
  1237	}
  1238	

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
  2026-06-01  9:18 [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size Eric Dumazet
  2026-06-01 10:17 ` Matthieu Baerts
  2026-06-01 17:52 ` kernel test robot
@ 2026-06-02  2:09 ` kernel test robot
  2026-06-02  2:19 ` kernel test robot
  2026-06-02  3:52 ` kernel test robot
  4 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2026-06-02  2:09 UTC (permalink / raw)
  To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
  Cc: oe-kbuild-all, Simon Horman, Neal Cardwell, Kuniyuki Iwashima,
	Matthieu Baerts, Mat Martineau, Geliang Tang, netdev,
	eric.dumazet, Eric Dumazet

Hi Eric,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/mptcp-change-mptcp_established_options-to-return-opt_size/20260601-174435
base:   net-next/main
patch link:    https://lore.kernel.org/r/20260601091816.444738-1-edumazet%40google.com
patch subject: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
config: i386-randconfig-007-20260602 (https://download.01.org/0day-ci/archive/20260602/202606021033.Gt2vODEq-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260602/202606021033.Gt2vODEq-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202606021033.Gt2vODEq-lkp@intel.com/

All errors (new ones prefixed by >>):

   net/ipv4/tcp_output.c: In function 'tcp_established_options':
>> net/ipv4/tcp_output.c:1186:63: error: passing argument 3 of 'mptcp_established_options' makes pointer from integer without a cast [-Wint-conversion]
    1186 |                 opt_size = mptcp_established_options(sk, skb, remaining,
         |                                                               ^~~~~~~~~
         |                                                               |
         |                                                               unsigned int
   In file included from include/net/tcp.h:44,
                    from net/ipv4/tcp_output.c:40:
   include/net/mptcp.h:271:59: note: expected 'unsigned int *' but argument is of type 'unsigned int'
     271 |                                             unsigned int *size,
         |                                             ~~~~~~~~~~~~~~^~~~
>> net/ipv4/tcp_output.c:1187:54: error: passing argument 4 of 'mptcp_established_options' makes integer from pointer without a cast [-Wint-conversion]
    1187 |                                                      &opts->mptcp);
         |                                                      ^~~~~~~~~~~~
         |                                                      |
         |                                                      struct mptcp_out_options *
   include/net/mptcp.h:272:58: note: expected 'unsigned int' but argument is of type 'struct mptcp_out_options *'
     272 |                                             unsigned int remaining,
         |                                             ~~~~~~~~~~~~~^~~~~~~~~
>> net/ipv4/tcp_output.c:1186:28: error: too few arguments to function 'mptcp_established_options'
    1186 |                 opt_size = mptcp_established_options(sk, skb, remaining,
         |                            ^~~~~~~~~~~~~~~~~~~~~~~~~
   include/net/mptcp.h:269:19: note: declared here
     269 | static inline int mptcp_established_options(struct sock *sk,
         |                   ^~~~~~~~~~~~~~~~~~~~~~~~~


vim +/mptcp_established_options +1186 net/ipv4/tcp_output.c

  1145	
  1146	/* Compute TCP options for ESTABLISHED sockets. This is not the
  1147	 * final wire format yet.
  1148	 */
  1149	static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb,
  1150						struct tcp_out_options *opts,
  1151						struct tcp_key *key)
  1152	{
  1153		struct tcp_sock *tp = tcp_sk(sk);
  1154		unsigned int size = 0;
  1155		unsigned int eff_sacks;
  1156	
  1157		opts->options = 0;
  1158	
  1159		/* Better than switch (key.type) as it has static branches */
  1160		if (tcp_key_is_md5(key)) {
  1161			opts->options |= OPTION_MD5;
  1162			size += TCPOLEN_MD5SIG_ALIGNED;
  1163		} else if (tcp_key_is_ao(key)) {
  1164			opts->options |= OPTION_AO;
  1165			size += tcp_ao_len_aligned(key->ao_key);
  1166		}
  1167	
  1168		if (likely(tp->rx_opt.tstamp_ok)) {
  1169			opts->options |= OPTION_TS;
  1170			opts->tsval = skb ? tcp_skb_timestamp_ts(tp->tcp_usec_ts, skb) +
  1171					tp->tsoffset : 0;
  1172			opts->tsecr = tp->rx_opt.ts_recent;
  1173			size += TCPOLEN_TSTAMP_ALIGNED;
  1174		}
  1175	
  1176		/* MPTCP options have precedence over SACK for the limited TCP
  1177		 * option space because a MPTCP connection would be forced to
  1178		 * fall back to regular TCP if a required multipath option is
  1179		 * missing. SACK still gets a chance to use whatever space is
  1180		 * left.
  1181		 */
  1182		if (sk_is_mptcp(sk)) {
  1183			unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1184			int opt_size;
  1185	
> 1186			opt_size = mptcp_established_options(sk, skb, remaining,
> 1187							     &opts->mptcp);
  1188			if (opt_size >= 0) {
  1189				opts->options |= OPTION_MPTCP;
  1190				size += opt_size;
  1191			}
  1192		}
  1193	
  1194		eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;
  1195		if (unlikely(eff_sacks)) {
  1196			const unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1197			if (likely(remaining >= TCPOLEN_SACK_BASE_ALIGNED +
  1198						TCPOLEN_SACK_PERBLOCK)) {
  1199				opts->num_sack_blocks =
  1200					min_t(unsigned int, eff_sacks,
  1201					      (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
  1202					      TCPOLEN_SACK_PERBLOCK);
  1203	
  1204				size += TCPOLEN_SACK_BASE_ALIGNED +
  1205					opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
  1206			} else {
  1207				opts->num_sack_blocks = 0;
  1208			}
  1209		} else {
  1210			opts->num_sack_blocks = 0;
  1211		}
  1212	
  1213		if (tcp_ecn_mode_accecn(tp)) {
  1214			int ecn_opt = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option);
  1215	
  1216			if (ecn_opt && tp->saw_accecn_opt &&
  1217			    (ecn_opt >= TCP_ACCECN_OPTION_PERSIST ||
  1218			     !tcp_accecn_opt_fail_send(tp)) &&
  1219			    (ecn_opt >= TCP_ACCECN_OPTION_FULL || tp->accecn_opt_demand ||
  1220			     tcp_accecn_option_beacon_check(sk))) {
  1221				opts->use_synack_ecn_bytes = 0;
  1222				size += tcp_options_fit_accecn(opts, tp->accecn_minlen,
  1223							       MAX_TCP_OPTION_SPACE - size);
  1224			}
  1225		}
  1226	
  1227		if (unlikely(BPF_SOCK_OPS_TEST_FLAG(tp,
  1228						    BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG))) {
  1229			unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1230	
  1231			bpf_skops_hdr_opt_len(sk, skb, NULL, NULL, 0, opts, &remaining);
  1232	
  1233			size = MAX_TCP_OPTION_SPACE - remaining;
  1234		}
  1235	
  1236		return size;
  1237	}
  1238	

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
  2026-06-01  9:18 [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size Eric Dumazet
                   ` (2 preceding siblings ...)
  2026-06-02  2:09 ` kernel test robot
@ 2026-06-02  2:19 ` kernel test robot
  2026-06-02  3:52 ` kernel test robot
  4 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2026-06-02  2:19 UTC (permalink / raw)
  To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
  Cc: oe-kbuild-all, Simon Horman, Neal Cardwell, Kuniyuki Iwashima,
	Matthieu Baerts, Mat Martineau, Geliang Tang, netdev,
	eric.dumazet, Eric Dumazet

Hi Eric,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/mptcp-change-mptcp_established_options-to-return-opt_size/20260601-174435
base:   net-next/main
patch link:    https://lore.kernel.org/r/20260601091816.444738-1-edumazet%40google.com
patch subject: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
config: powerpc-arches_defconfig (https://download.01.org/0day-ci/archive/20260602/202606021023.2uNktNr0-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260602/202606021023.2uNktNr0-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202606021023.2uNktNr0-lkp@intel.com/

All errors (new ones prefixed by >>):

   net/ipv4/tcp_output.c: In function 'tcp_established_options':
   net/ipv4/tcp_output.c:1186:63: error: passing argument 3 of 'mptcp_established_options' makes pointer from integer without a cast [-Wint-conversion]
    1186 |                 opt_size = mptcp_established_options(sk, skb, remaining,
         |                                                               ^~~~~~~~~
         |                                                               |
         |                                                               unsigned int
   net/ipv4/tcp_output.c:1186:63: note: possible fix: take the address with '&'
    1186 |                 opt_size = mptcp_established_options(sk, skb, remaining,
         |                                                               ^~~~~~~~~
         |                                                               &
   In file included from include/net/tcp.h:44,
                    from net/ipv4/tcp_output.c:40:
   include/net/mptcp.h:271:59: note: expected 'unsigned int *' but argument is of type 'unsigned int'
     271 |                                             unsigned int *size,
         |                                             ~~~~~~~~~~~~~~^~~~
   net/ipv4/tcp_output.c:1187:54: error: passing argument 4 of 'mptcp_established_options' makes integer from pointer without a cast [-Wint-conversion]
    1187 |                                                      &opts->mptcp);
         |                                                      ^~~~~~~~~~~~
         |                                                      |
         |                                                      struct mptcp_out_options *
   include/net/mptcp.h:272:58: note: expected 'unsigned int' but argument is of type 'struct mptcp_out_options *'
     272 |                                             unsigned int remaining,
         |                                             ~~~~~~~~~~~~~^~~~~~~~~
>> net/ipv4/tcp_output.c:1186:28: error: too few arguments to function 'mptcp_established_options'; expected 5, have 4
    1186 |                 opt_size = mptcp_established_options(sk, skb, remaining,
         |                            ^~~~~~~~~~~~~~~~~~~~~~~~~
   include/net/mptcp.h:269:19: note: declared here
     269 | static inline int mptcp_established_options(struct sock *sk,
         |                   ^~~~~~~~~~~~~~~~~~~~~~~~~


vim +/mptcp_established_options +1186 net/ipv4/tcp_output.c

  1145	
  1146	/* Compute TCP options for ESTABLISHED sockets. This is not the
  1147	 * final wire format yet.
  1148	 */
  1149	static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb,
  1150						struct tcp_out_options *opts,
  1151						struct tcp_key *key)
  1152	{
  1153		struct tcp_sock *tp = tcp_sk(sk);
  1154		unsigned int size = 0;
  1155		unsigned int eff_sacks;
  1156	
  1157		opts->options = 0;
  1158	
  1159		/* Better than switch (key.type) as it has static branches */
  1160		if (tcp_key_is_md5(key)) {
  1161			opts->options |= OPTION_MD5;
  1162			size += TCPOLEN_MD5SIG_ALIGNED;
  1163		} else if (tcp_key_is_ao(key)) {
  1164			opts->options |= OPTION_AO;
  1165			size += tcp_ao_len_aligned(key->ao_key);
  1166		}
  1167	
  1168		if (likely(tp->rx_opt.tstamp_ok)) {
  1169			opts->options |= OPTION_TS;
  1170			opts->tsval = skb ? tcp_skb_timestamp_ts(tp->tcp_usec_ts, skb) +
  1171					tp->tsoffset : 0;
  1172			opts->tsecr = tp->rx_opt.ts_recent;
  1173			size += TCPOLEN_TSTAMP_ALIGNED;
  1174		}
  1175	
  1176		/* MPTCP options have precedence over SACK for the limited TCP
  1177		 * option space because a MPTCP connection would be forced to
  1178		 * fall back to regular TCP if a required multipath option is
  1179		 * missing. SACK still gets a chance to use whatever space is
  1180		 * left.
  1181		 */
  1182		if (sk_is_mptcp(sk)) {
  1183			unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1184			int opt_size;
  1185	
> 1186			opt_size = mptcp_established_options(sk, skb, remaining,
  1187							     &opts->mptcp);
  1188			if (opt_size >= 0) {
  1189				opts->options |= OPTION_MPTCP;
  1190				size += opt_size;
  1191			}
  1192		}
  1193	
  1194		eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;
  1195		if (unlikely(eff_sacks)) {
  1196			const unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1197			if (likely(remaining >= TCPOLEN_SACK_BASE_ALIGNED +
  1198						TCPOLEN_SACK_PERBLOCK)) {
  1199				opts->num_sack_blocks =
  1200					min_t(unsigned int, eff_sacks,
  1201					      (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
  1202					      TCPOLEN_SACK_PERBLOCK);
  1203	
  1204				size += TCPOLEN_SACK_BASE_ALIGNED +
  1205					opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
  1206			} else {
  1207				opts->num_sack_blocks = 0;
  1208			}
  1209		} else {
  1210			opts->num_sack_blocks = 0;
  1211		}
  1212	
  1213		if (tcp_ecn_mode_accecn(tp)) {
  1214			int ecn_opt = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option);
  1215	
  1216			if (ecn_opt && tp->saw_accecn_opt &&
  1217			    (ecn_opt >= TCP_ACCECN_OPTION_PERSIST ||
  1218			     !tcp_accecn_opt_fail_send(tp)) &&
  1219			    (ecn_opt >= TCP_ACCECN_OPTION_FULL || tp->accecn_opt_demand ||
  1220			     tcp_accecn_option_beacon_check(sk))) {
  1221				opts->use_synack_ecn_bytes = 0;
  1222				size += tcp_options_fit_accecn(opts, tp->accecn_minlen,
  1223							       MAX_TCP_OPTION_SPACE - size);
  1224			}
  1225		}
  1226	
  1227		if (unlikely(BPF_SOCK_OPS_TEST_FLAG(tp,
  1228						    BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG))) {
  1229			unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1230	
  1231			bpf_skops_hdr_opt_len(sk, skb, NULL, NULL, 0, opts, &remaining);
  1232	
  1233			size = MAX_TCP_OPTION_SPACE - remaining;
  1234		}
  1235	
  1236		return size;
  1237	}
  1238	

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
  2026-06-01  9:18 [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size Eric Dumazet
                   ` (3 preceding siblings ...)
  2026-06-02  2:19 ` kernel test robot
@ 2026-06-02  3:52 ` kernel test robot
  4 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2026-06-02  3:52 UTC (permalink / raw)
  To: Eric Dumazet, David S . Miller, Jakub Kicinski, Paolo Abeni
  Cc: oe-kbuild-all, Simon Horman, Neal Cardwell, Kuniyuki Iwashima,
	Matthieu Baerts, Mat Martineau, Geliang Tang, netdev,
	eric.dumazet, Eric Dumazet

Hi Eric,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/mptcp-change-mptcp_established_options-to-return-opt_size/20260601-174435
base:   net-next/main
patch link:    https://lore.kernel.org/r/20260601091816.444738-1-edumazet%40google.com
patch subject: [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size
config: nios2-defconfig (https://download.01.org/0day-ci/archive/20260602/202606021113.tfn0OswA-lkp@intel.com/config)
compiler: nios2-linux-gcc (GCC) 11.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260602/202606021113.tfn0OswA-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202606021113.tfn0OswA-lkp@intel.com/

All warnings (new ones prefixed by >>):

   net/ipv4/tcp_output.c: In function 'tcp_established_options':
>> net/ipv4/tcp_output.c:1186:63: warning: passing argument 3 of 'mptcp_established_options' makes pointer from integer without a cast [-Wint-conversion]
    1186 |                 opt_size = mptcp_established_options(sk, skb, remaining,
         |                                                               ^~~~~~~~~
         |                                                               |
         |                                                               unsigned int
   In file included from include/net/tcp.h:44,
                    from net/ipv4/tcp_output.c:40:
   include/net/mptcp.h:271:59: note: expected 'unsigned int *' but argument is of type 'unsigned int'
     271 |                                             unsigned int *size,
         |                                             ~~~~~~~~~~~~~~^~~~
>> net/ipv4/tcp_output.c:1187:54: warning: passing argument 4 of 'mptcp_established_options' makes integer from pointer without a cast [-Wint-conversion]
    1187 |                                                      &opts->mptcp);
         |                                                      ^~~~~~~~~~~~
         |                                                      |
         |                                                      struct mptcp_out_options *
   In file included from include/net/tcp.h:44,
                    from net/ipv4/tcp_output.c:40:
   include/net/mptcp.h:272:58: note: expected 'unsigned int' but argument is of type 'struct mptcp_out_options *'
     272 |                                             unsigned int remaining,
         |                                             ~~~~~~~~~~~~~^~~~~~~~~
   net/ipv4/tcp_output.c:1186:28: error: too few arguments to function 'mptcp_established_options'
    1186 |                 opt_size = mptcp_established_options(sk, skb, remaining,
         |                            ^~~~~~~~~~~~~~~~~~~~~~~~~
   In file included from include/net/tcp.h:44,
                    from net/ipv4/tcp_output.c:40:
   include/net/mptcp.h:269:19: note: declared here
     269 | static inline int mptcp_established_options(struct sock *sk,
         |                   ^~~~~~~~~~~~~~~~~~~~~~~~~


vim +/mptcp_established_options +1186 net/ipv4/tcp_output.c

  1145	
  1146	/* Compute TCP options for ESTABLISHED sockets. This is not the
  1147	 * final wire format yet.
  1148	 */
  1149	static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb,
  1150						struct tcp_out_options *opts,
  1151						struct tcp_key *key)
  1152	{
  1153		struct tcp_sock *tp = tcp_sk(sk);
  1154		unsigned int size = 0;
  1155		unsigned int eff_sacks;
  1156	
  1157		opts->options = 0;
  1158	
  1159		/* Better than switch (key.type) as it has static branches */
  1160		if (tcp_key_is_md5(key)) {
  1161			opts->options |= OPTION_MD5;
  1162			size += TCPOLEN_MD5SIG_ALIGNED;
  1163		} else if (tcp_key_is_ao(key)) {
  1164			opts->options |= OPTION_AO;
  1165			size += tcp_ao_len_aligned(key->ao_key);
  1166		}
  1167	
  1168		if (likely(tp->rx_opt.tstamp_ok)) {
  1169			opts->options |= OPTION_TS;
  1170			opts->tsval = skb ? tcp_skb_timestamp_ts(tp->tcp_usec_ts, skb) +
  1171					tp->tsoffset : 0;
  1172			opts->tsecr = tp->rx_opt.ts_recent;
  1173			size += TCPOLEN_TSTAMP_ALIGNED;
  1174		}
  1175	
  1176		/* MPTCP options have precedence over SACK for the limited TCP
  1177		 * option space because a MPTCP connection would be forced to
  1178		 * fall back to regular TCP if a required multipath option is
  1179		 * missing. SACK still gets a chance to use whatever space is
  1180		 * left.
  1181		 */
  1182		if (sk_is_mptcp(sk)) {
  1183			unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1184			int opt_size;
  1185	
> 1186			opt_size = mptcp_established_options(sk, skb, remaining,
> 1187							     &opts->mptcp);
  1188			if (opt_size >= 0) {
  1189				opts->options |= OPTION_MPTCP;
  1190				size += opt_size;
  1191			}
  1192		}
  1193	
  1194		eff_sacks = tp->rx_opt.num_sacks + tp->rx_opt.dsack;
  1195		if (unlikely(eff_sacks)) {
  1196			const unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1197			if (likely(remaining >= TCPOLEN_SACK_BASE_ALIGNED +
  1198						TCPOLEN_SACK_PERBLOCK)) {
  1199				opts->num_sack_blocks =
  1200					min_t(unsigned int, eff_sacks,
  1201					      (remaining - TCPOLEN_SACK_BASE_ALIGNED) /
  1202					      TCPOLEN_SACK_PERBLOCK);
  1203	
  1204				size += TCPOLEN_SACK_BASE_ALIGNED +
  1205					opts->num_sack_blocks * TCPOLEN_SACK_PERBLOCK;
  1206			} else {
  1207				opts->num_sack_blocks = 0;
  1208			}
  1209		} else {
  1210			opts->num_sack_blocks = 0;
  1211		}
  1212	
  1213		if (tcp_ecn_mode_accecn(tp)) {
  1214			int ecn_opt = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option);
  1215	
  1216			if (ecn_opt && tp->saw_accecn_opt &&
  1217			    (ecn_opt >= TCP_ACCECN_OPTION_PERSIST ||
  1218			     !tcp_accecn_opt_fail_send(tp)) &&
  1219			    (ecn_opt >= TCP_ACCECN_OPTION_FULL || tp->accecn_opt_demand ||
  1220			     tcp_accecn_option_beacon_check(sk))) {
  1221				opts->use_synack_ecn_bytes = 0;
  1222				size += tcp_options_fit_accecn(opts, tp->accecn_minlen,
  1223							       MAX_TCP_OPTION_SPACE - size);
  1224			}
  1225		}
  1226	
  1227		if (unlikely(BPF_SOCK_OPS_TEST_FLAG(tp,
  1228						    BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG))) {
  1229			unsigned int remaining = MAX_TCP_OPTION_SPACE - size;
  1230	
  1231			bpf_skops_hdr_opt_len(sk, skb, NULL, NULL, 0, opts, &remaining);
  1232	
  1233			size = MAX_TCP_OPTION_SPACE - remaining;
  1234		}
  1235	
  1236		return size;
  1237	}
  1238	

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2026-06-02  3:53 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-06-01  9:18 [PATCH net-next] mptcp: change mptcp_established_options() to return opt_size Eric Dumazet
2026-06-01 10:17 ` Matthieu Baerts
2026-06-01 17:52 ` kernel test robot
2026-06-02  2:09 ` kernel test robot
2026-06-02  2:19 ` kernel test robot
2026-06-02  3:52 ` kernel test robot

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