From 69318b5215f2dc32c345a3d65b98b4b1bf29c007 Mon Sep 17 00:00:00 2001 From: Ursula Braun Date: Mon, 21 Oct 2019 16:13:10 +0200 Subject: [PATCH] net/smc: improve abnormal termination locking Locking hierarchy requires that the link group conns_lock can be taken if the socket lock is held, but not vice versa. Nevertheless socket termination during abnormal link group termination should be protected by the socket lock. This patch reduces the time segments the link group conns_lock is held to enable usage of lock_sock in smc_lgr_terminate(). Signed-off-by: Ursula Braun Signed-off-by: Karsten Graul Signed-off-by: Jakub Kicinski --- net/smc/smc_core.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index b53ba8f0a833..1f58cd82928c 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -491,23 +491,26 @@ static void __smc_lgr_terminate(struct smc_link_group *lgr) if (!lgr->is_smcd) smc_llc_link_inactive(&lgr->lnk[SMC_SINGLE_LINK]); - write_lock_bh(&lgr->conns_lock); + /* kill remaining link group connections */ + read_lock_bh(&lgr->conns_lock); node = rb_first(&lgr->conns_all); while (node) { + read_unlock_bh(&lgr->conns_lock); conn = rb_entry(node, struct smc_connection, alert_node); smc = container_of(conn, struct smc_sock, conn); + lock_sock(&smc->sk); sock_hold(&smc->sk); /* sock_put in close work */ conn->killed = 1; conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1; - __smc_lgr_unregister_conn(conn); + smc_lgr_unregister_conn(conn); conn->lgr = NULL; - write_unlock_bh(&lgr->conns_lock); if (!schedule_work(&conn->close_work)) sock_put(&smc->sk); - write_lock_bh(&lgr->conns_lock); + release_sock(&smc->sk); + read_lock_bh(&lgr->conns_lock); node = rb_first(&lgr->conns_all); } - write_unlock_bh(&lgr->conns_lock); + read_unlock_bh(&lgr->conns_lock); if (!lgr->is_smcd) wake_up(&lgr->lnk[SMC_SINGLE_LINK].wr_reg_wait); smc_lgr_schedule_free_work(lgr);