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Commit e63a8e19 authored by Roland Dreier's avatar Roland Dreier Committed by Nicholas Bellinger
Browse files

target: Make locking in transport_deregister_session() IRQ safe 



At least the tcm_qla2xxx fabric driver calls into transport_deregister_session()
while holding an IRQ-disabled spinlock, so the inner locking needs to
use spin_lock_irqsave() instead of spin_lock_bh().

This fixes warnings seen with tcm_qla2xxx like:

    WARNING: at kernel/softirq.c:159 local_bh_enable_ip+0x98/0xb0()
    Call Trace:
     [<ffffffff8104e65f>] warn_slowpath_common+0x7f/0xc0
     [<ffffffff8104e6ba>] warn_slowpath_null+0x1a/0x20
     [<ffffffff81055368>] local_bh_enable_ip+0x98/0xb0
     [<ffffffff814d5284>] _raw_spin_unlock_bh+0x14/0x20
     [<ffffffffa027b7f6>] transport_deregister_session+0x96/0x180 [target_core_mod]
     [<ffffffffa00f7731>] tcm_qla2xxx_free_session+0xd1/0x170 [tcm_qla2xxx]
     [<ffffffffa01b9173>] qla_tgt_sess_put+0xc3/0x140 [qla2xxx]
     [<ffffffffa01bf40f>] qla_tgt_stop_phase1+0x8f/0x2c0 [qla2xxx]
     [<ffffffffa00f735e>] tcm_qla2xxx_tpg_store_enable+0x6e/0xd0 [tcm_qla2xxx]
     [<ffffffffa026ca29>] target_fabric_tpg_attr_store+0x39/0x40 [target_core_mod]
     [<ffffffffa00a575d>] configfs_write_file+0xbd/0x120 [configfs]
     [<ffffffff811464a6>] vfs_write+0xc6/0x180
     [<ffffffff811467c1>] sys_write+0x51/0x90
     [<ffffffff814dd382>] system_call_fastpath+0x16/0x1b

Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 4e0f0529

drivers/target/target_core_transport.c

+7 −6
Original line number Diff line number Diff line
@@ -389,17 +389,18 @@ void transport_deregister_session(struct se_session *se_sess) 
{

	struct se_portal_group *se_tpg = se_sess->se_tpg;

	struct se_node_acl *se_nacl;

	unsigned long flags;



	if (!se_tpg) {

		transport_free_session(se_sess);

		return;

	}



	spin_lock_bh(&se_tpg->session_lock);

	spin_lock_irqsave(&se_tpg->session_lock, flags);

	list_del(&se_sess->sess_list);

	se_sess->se_tpg = NULL;

	se_sess->fabric_sess_ptr = NULL;

	spin_unlock_bh(&se_tpg->session_lock);

	spin_unlock_irqrestore(&se_tpg->session_lock, flags);



	/*

	 * Determine if we need to do extra work for this initiator node's
@@ -407,22 +408,22 @@ void transport_deregister_session(struct se_session *se_sess) 
	 */

	se_nacl = se_sess->se_node_acl;

	if (se_nacl) {

		spin_lock_bh(&se_tpg->acl_node_lock);

		spin_lock_irqsave(&se_tpg->acl_node_lock, flags);

		if (se_nacl->dynamic_node_acl) {

			if (!se_tpg->se_tpg_tfo->tpg_check_demo_mode_cache(

					se_tpg)) {

				list_del(&se_nacl->acl_list);

				se_tpg->num_node_acls--;

				spin_unlock_bh(&se_tpg->acl_node_lock);

				spin_unlock_irqrestore(&se_tpg->acl_node_lock, flags);



				core_tpg_wait_for_nacl_pr_ref(se_nacl);

				core_free_device_list_for_node(se_nacl, se_tpg);

				se_tpg->se_tpg_tfo->tpg_release_fabric_acl(se_tpg,

						se_nacl);

				spin_lock_bh(&se_tpg->acl_node_lock);

				spin_lock_irqsave(&se_tpg->acl_node_lock, flags);

			}

		}

		spin_unlock_bh(&se_tpg->acl_node_lock);

		spin_unlock_irqrestore(&se_tpg->acl_node_lock, flags);

	}



	transport_free_session(se_sess);