diff mbox series

[net-next,1/4] mptcp: stop using the mptcp_has_another_subflow() helper

Message ID 20220518220446.209750-2-mathew.j.martineau@linux.intel.com (mailing list archive)
State Accepted
Commit 7b16871f9932d8a371488d2967b033387870a747
Delegated to: Netdev Maintainers
Headers show
Series mptcp: Miscellaneous fixes and a new test case | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/cc_maintainers success CCed 9 of 9 maintainers
netdev/build_clang success Errors and warnings before: 12 this patch: 12
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 5 this patch: 5
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 36 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Mat Martineau May 18, 2022, 10:04 p.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

The mentioned helper requires the msk socket lock, and the
current callers don't own it nor can't acquire it, so the
access is racy.

All the current callers are really checking for infinite mapping
fallback, and the latter condition is explicitly tracked by
the relevant msk variable: we can safely remove the caller usage
- and the caller itself.

The issue is present since MP_FAIL implementation, but the
fix only applies since the infinite fallback support, ence the
somewhat unexpected fixes tag.

Fixes: 0530020a7c8f ("mptcp: track and update contiguous data status")
Acked-and-tested-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm.c       |  2 +-
 net/mptcp/protocol.h | 13 -------------
 net/mptcp/subflow.c  |  3 +--
 3 files changed, 2 insertions(+), 16 deletions(-)
diff mbox series

Patch

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index cdc2d79071f8..a3f9bf8e8912 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -304,7 +304,7 @@  void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq)
 
 	pr_debug("fail_seq=%llu", fail_seq);
 
-	if (mptcp_has_another_subflow(sk) || !READ_ONCE(msk->allow_infinite_fallback))
+	if (!READ_ONCE(msk->allow_infinite_fallback))
 		return;
 
 	if (!READ_ONCE(subflow->mp_fail_response_expect)) {
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 4672901d0dfe..91f7ef6e6c56 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -649,19 +649,6 @@  static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
 	inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
 }
 
-static inline bool mptcp_has_another_subflow(struct sock *ssk)
-{
-	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk), *tmp;
-	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
-
-	mptcp_for_each_subflow(msk, tmp) {
-		if (tmp != subflow)
-			return true;
-	}
-
-	return false;
-}
-
 void __init mptcp_proto_init(void);
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 int __init mptcp_proto_v6_init(void);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 6d59336a8e1e..1e07b4d7ee7b 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1218,8 +1218,7 @@  static bool subflow_check_data_avail(struct sock *ssk)
 	if (!__mptcp_check_fallback(msk)) {
 		/* RFC 8684 section 3.7. */
 		if (subflow->send_mp_fail) {
-			if (mptcp_has_another_subflow(ssk) ||
-			    !READ_ONCE(msk->allow_infinite_fallback)) {
+			if (!READ_ONCE(msk->allow_infinite_fallback)) {
 				ssk->sk_err = EBADMSG;
 				tcp_set_state(ssk, TCP_CLOSE);
 				subflow->reset_transient = 0;