Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751438AbdFAGvO (ORCPT ); Thu, 1 Jun 2017 02:51:14 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:57743 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751053AbdFAGvM (ORCPT ); Thu, 1 Jun 2017 02:51:12 -0400 From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , lkml , Nicholas Bellinger , Christoph Hellwig , Mike Christie , Hannes Reinecke Subject: [PATCH] target: Avoid target_shutdown_sessions loop during queue_depth change Date: Thu, 1 Jun 2017 06:54:06 +0000 Message-Id: <1496300046-21234-1-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: 3238 Lines: 98 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 move sessions into a local list and avoid draining the same session multiple times 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. Cc: Christoph Hellwig Cc: Mike Christie Cc: Hannes Reinecke Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_tpg.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c index 310d9e5..7a7c2b5 100644 --- a/drivers/target/target_core_tpg.c +++ b/drivers/target/target_core_tpg.c @@ -336,10 +336,11 @@ 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; unsigned long flags; + LIST_HEAD(tmp_list); restart: spin_lock_irqsave(&acl->nacl_sess_lock, flags); @@ -347,14 +348,22 @@ static void target_shutdown_sessions(struct se_node_acl *acl) if (sess->sess_tearing_down) continue; + list_move_tail(&sess->sess_acl_list, &tmp_list); + } + spin_unlock_irqrestore(&acl->nacl_sess_lock, flags); + + if (list_empty(&tmp_list)) + return; + + list_for_each_entry(sess, &tmp_list, sess_acl_list) { list_del_init(&sess->sess_acl_list); - spin_unlock_irqrestore(&acl->nacl_sess_lock, flags); if (acl->se_tpg->se_tpg_tfo->close_session) acl->se_tpg->se_tpg_tfo->close_session(sess); - goto restart; } - spin_unlock_irqrestore(&acl->nacl_sess_lock, flags); + + if (do_restart) + goto restart; } void core_tpg_del_initiator_node_acl(struct se_node_acl *acl) @@ -367,7 +376,7 @@ 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 +423,7 @@ 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