From 9b31a328e344e62e7cc98ae574edcb7b674719bb Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Wed, 15 May 2013 00:52:44 -0700 Subject: target: Re-instate sess_wait_list for target_wait_for_sess_cmds Switch back to pre commit 1c7b13fe652 list splicing logic for active I/O shutdown with tcm_qla2xxx + ib_srpt fabrics. The original commit was done under the incorrect assumption that it's safe to walk se_sess->sess_cmd_list unprotected in target_wait_for_sess_cmds() after sess->sess_tearing_down = 1 has been set by target_sess_cmd_list_set_waiting() during session shutdown. So instead of adding sess->sess_cmd_lock protection around sess->sess_cmd_list during target_wait_for_sess_cmds(), switch back to sess->sess_wait_list to allow wait_for_completion() + TFO->release_cmd() to occur without having to walk ->sess_cmd_list after the list_splice. Also add a check to exit if target_sess_cmd_list_set_waiting() has already been called, and add a WARN_ON to check for any fabric bug where new se_cmds are added to sess->sess_cmd_list after sess->sess_tearing_down = 1 has already been set. Cc: Joern Engel Cc: Roland Dreier Cc: stable@vger.kernel.org Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_transport.c | 18 ++++++++++++++---- include/target/target_core_base.h | 1 + 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 311c11349aab..bbca144821c5 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -221,6 +221,7 @@ struct se_session *transport_init_session(void) INIT_LIST_HEAD(&se_sess->sess_list); INIT_LIST_HEAD(&se_sess->sess_acl_list); INIT_LIST_HEAD(&se_sess->sess_cmd_list); + INIT_LIST_HEAD(&se_sess->sess_wait_list); spin_lock_init(&se_sess->sess_cmd_lock); kref_init(&se_sess->sess_kref); @@ -2250,11 +2251,14 @@ void target_sess_cmd_list_set_waiting(struct se_session *se_sess) unsigned long flags; spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); - - WARN_ON(se_sess->sess_tearing_down); + if (se_sess->sess_tearing_down) { + spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + return; + } se_sess->sess_tearing_down = 1; + list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list); - list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) + list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list) se_cmd->cmd_wait_set = 1; spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); @@ -2267,9 +2271,10 @@ EXPORT_SYMBOL(target_sess_cmd_list_set_waiting); void target_wait_for_sess_cmds(struct se_session *se_sess) { struct se_cmd *se_cmd, *tmp_cmd; + unsigned long flags; list_for_each_entry_safe(se_cmd, tmp_cmd, - &se_sess->sess_cmd_list, se_cmd_list) { + &se_sess->sess_wait_list, se_cmd_list) { list_del(&se_cmd->se_cmd_list); pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:" @@ -2283,6 +2288,11 @@ void target_wait_for_sess_cmds(struct se_session *se_sess) se_cmd->se_tfo->release_cmd(se_cmd); } + + spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); + WARN_ON(!list_empty(&se_sess->sess_cmd_list)); + spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + } EXPORT_SYMBOL(target_wait_for_sess_cmds); diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index e773dfa5f98f..4ea4f985f394 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -543,6 +543,7 @@ struct se_session { struct list_head sess_list; struct list_head sess_acl_list; struct list_head sess_cmd_list; + struct list_head sess_wait_list; spinlock_t sess_cmd_lock; struct kref sess_kref; }; -- cgit v1.2.3-59-g8ed1b