Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751168AbdFBDIj (ORCPT ); Thu, 1 Jun 2017 23:08:39 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:47460 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751122AbdFBDIh (ORCPT ); Thu, 1 Jun 2017 23:08:37 -0400 From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , lkml , Nicholas Bellinger , Christoph Hellwig , Mike Christie , Hannes Reinecke Subject: [PATCH-v2] target: Avoid target_shutdown_sessions loop during queue_depth change Date: Fri, 2 Jun 2017 03:11:33 +0000 Message-Id: <1496373093-8852-1-git-send-email-nab@linux-iscsi.org> X-Mailer: git-send-email 1.7.2.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3318 Lines: 95 From: Nicholas Bellinger When target_shutdown_sessions() is invoked to shutdown all active sessions associated with a se_node_acl when se_node_acl->queue_depth is changed via core_tpg_set_initiator_node_queue_depth(), it's possible that new connections reconnect immediately after explicit shutdown occurs via target_shutdown_sessions(). Which means it's possible for the newly reconnected session with the proper queue_depth can be shutdown multiple times when target_shutdown_sessions() loops to drain all active sessions for all cases. This was regression was introduced by: commit bc6e6bb470eda42f44bcac96c261cff1216577b3 Author: Christoph Hellwig Date: Mon May 2 15:45:19 2016 +0200 target: consolidate and fix session shutdown To avoid this case, instead change target_shutdown_sessions() to pass 'do_restart' and avoid the looping drain of sessions when invoked via core_tpg_set_initiator_node_queue_depth(), but still loop during normal se_node_acl delete until all associated sessions have been shutdown. (v2 - go back to the original version instead of a local list, in order to protect list_del_init(&sess->sess_acl_list) from transport_deregister_session_configfs. Also use safe list walking in target_shutdown_sessions - nab) Cc: Christoph Hellwig Cc: Mike Christie Cc: Hannes Reinecke Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_tpg.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c index 3691373..1b2b60e 100644 --- a/drivers/target/target_core_tpg.c +++ b/drivers/target/target_core_tpg.c @@ -336,14 +336,14 @@ struct se_node_acl *core_tpg_add_initiator_node_acl( return acl; } -static void target_shutdown_sessions(struct se_node_acl *acl) +static void target_shutdown_sessions(struct se_node_acl *acl, bool do_restart) { - struct se_session *sess; + struct se_session *sess, *sess_tmp; unsigned long flags; restart: spin_lock_irqsave(&acl->nacl_sess_lock, flags); - list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) { + list_for_each_entry_safe(sess, sess_tmp, &acl->acl_sess_list, sess_acl_list) { if (sess->sess_tearing_down) continue; @@ -352,7 +352,11 @@ static void target_shutdown_sessions(struct se_node_acl *acl) if (acl->se_tpg->se_tpg_tfo->close_session) acl->se_tpg->se_tpg_tfo->close_session(sess); - goto restart; + + if (do_restart) + goto restart; + + spin_lock_irqsave(&acl->nacl_sess_lock, flags); } spin_unlock_irqrestore(&acl->nacl_sess_lock, flags); } @@ -367,7 +371,7 @@ void core_tpg_del_initiator_node_acl(struct se_node_acl *acl) list_del(&acl->acl_list); mutex_unlock(&tpg->acl_node_mutex); - target_shutdown_sessions(acl); + target_shutdown_sessions(acl, true); target_put_nacl(acl); /* @@ -414,7 +418,7 @@ int core_tpg_set_initiator_node_queue_depth( /* * Shutdown all pending sessions to force session reinstatement. */ - target_shutdown_sessions(acl); + target_shutdown_sessions(acl, false); pr_debug("Successfully changed queue depth to: %d for Initiator" " Node: %s on %s Target Portal Group: %u\n", acl->queue_depth, -- 1.9.1