diff mbox series

[net,4/7] mptcp: pm: don't try to create sf if alloc failed

Message ID 20240731-upstream-net-20240731-mptcp-endp-subflow-signal-v1-4-c8a9b036493b@kernel.org (mailing list archive)
State Accepted
Commit cd7c957f936f8cb80d03e5152f4013aae65bd986
Delegated to: Netdev Maintainers
Headers show
Series mptcp: fix endpoints with 'signal' and 'subflow' flags | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 42 this patch: 42
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 43 this patch: 43
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 45 this patch: 45
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 32 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-07-31--15-00 (tests: 707)

Commit Message

Matthieu Baerts (NGI0) July 31, 2024, 11:05 a.m. UTC
It sounds better to avoid wasting cycles and / or put extreme memory
pressure on the system by trying to create new subflows if it was not
possible to add a new item in the announce list.

While at it, a warning is now printed if the entry was already in the
list as it should not happen with the in-kernel path-manager. With this
PM, mptcp_pm_alloc_anno_list() should only fail in case of memory
pressure.

Fixes: b6c08380860b ("mptcp: remove addr and subflow in PM netlink")
Cc: stable@vger.kernel.org
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_netlink.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 780f4cca165c..2be7af377cda 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -348,7 +348,7 @@  bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
 	add_entry = mptcp_lookup_anno_list_by_saddr(msk, addr);
 
 	if (add_entry) {
-		if (mptcp_pm_is_kernel(msk))
+		if (WARN_ON_ONCE(mptcp_pm_is_kernel(msk)))
 			return false;
 
 		sk_reset_timer(sk, &add_entry->add_timer,
@@ -555,8 +555,6 @@  static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 
 	/* check first for announce */
 	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
-		local = select_signal_address(pernet, msk);
-
 		/* due to racing events on both ends we can reach here while
 		 * previous add address is still running: if we invoke now
 		 * mptcp_pm_announce_addr(), that will fail and the
@@ -567,11 +565,15 @@  static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 		if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
 			return;
 
+		local = select_signal_address(pernet, msk);
 		if (!local)
 			goto subflow;
 
+		/* If the alloc fails, we are on memory pressure, not worth
+		 * continuing, and trying to create subflows.
+		 */
 		if (!mptcp_pm_alloc_anno_list(msk, &local->addr))
-			goto subflow;
+			return;
 
 		__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
 		msk->pm.add_addr_signaled++;