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target: Make locking in transport_deregister_session() IRQ safe

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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: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Roland Dreier 2011-08-12 16:01:02 -07:00 committed by Nicholas Bellinger
parent 4e0f05297f
commit e63a8e1933
1 changed files with 7 additions and 6 deletions
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13
drivers/target/target_core_transport.c
View file

@ -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_portal_group *se_tpg = se_sess->se_tpg;
struct se_node_acl *se_nacl; struct se_node_acl *se_nacl;
unsigned long flags;
if (!se_tpg) { if (!se_tpg) {
transport_free_session(se_sess); transport_free_session(se_sess);
return; return;
} }
spin_lock_bh(&se_tpg->session_lock); spin_lock_irqsave(&se_tpg->session_lock, flags);
list_del(&se_sess->sess_list); list_del(&se_sess->sess_list);
se_sess->se_tpg = NULL; se_sess->se_tpg = NULL;
se_sess->fabric_sess_ptr = 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 * 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; se_nacl = se_sess->se_node_acl;
if (se_nacl) { 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_nacl->dynamic_node_acl) {
if (!se_tpg->se_tpg_tfo->tpg_check_demo_mode_cache( if (!se_tpg->se_tpg_tfo->tpg_check_demo_mode_cache(
se_tpg)) { se_tpg)) {
list_del(&se_nacl->acl_list); list_del(&se_nacl->acl_list);
se_tpg->num_node_acls--; 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_tpg_wait_for_nacl_pr_ref(se_nacl);
core_free_device_list_for_node(se_nacl, se_tpg); core_free_device_list_for_node(se_nacl, se_tpg);
se_tpg->se_tpg_tfo->tpg_release_fabric_acl(se_tpg, se_tpg->se_tpg_tfo->tpg_release_fabric_acl(se_tpg,
se_nacl); 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); transport_free_session(se_sess);