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scsi: qla2xxx: Fixup locking for session deletion
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Commit d8630bb ('Serialize session deletion by using work_lock')
tries to fixup a deadlock when deleting sessions, but fails to take into
account the locking rules. This patch resolves the situation by
introducing a separate lock for processing the GNLIST response, and
ensures that sess_lock is released before calling
qlt_schedule_sess_delete().

Cc: Himanshu Madhani <himanshu.madhani@cavium.com>
Cc: Quinn Tran <quinn.tran@cavium.com>
Fixes: d8630bb ("scsi: qla2xxx: Serialize session deletion by using work_lock")
Signed-off-by: Hannes Reinecke <hare@suse.com>
Acked-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Hannes Reinecke authored and Martin K. Petersen committed Mar 2, 2018
1 parent 1514839 commit 1c6cacf
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Showing 4 changed files with 29 additions and 23 deletions.
4 changes: 2 additions & 2 deletions drivers/scsi/qla2xxx/qla_def.h
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Original file line number Diff line number Diff line change
Expand Up @@ -261,9 +261,9 @@
struct name_list_extended {
struct get_name_list_extended *l;
dma_addr_t ldma;
struct list_head fcports; /* protect by sess_list */
struct list_head fcports;
spinlock_t fcports_lock;
u32 size;
u8 sent;
};
/*
* Timeout timer counts in seconds
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24 changes: 15 additions & 9 deletions drivers/scsi/qla2xxx/qla_init.c
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Original file line number Diff line number Diff line change
Expand Up @@ -643,8 +643,7 @@ qla24xx_async_gnl_sp_done(void *s, int res)
(loop_id & 0x7fff));
}

spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
vha->gnl.sent = 0;
spin_lock_irqsave(&vha->gnl.fcports_lock, flags);

INIT_LIST_HEAD(&h);
fcport = tf = NULL;
Expand All @@ -653,12 +652,16 @@ qla24xx_async_gnl_sp_done(void *s, int res)

list_for_each_entry_safe(fcport, tf, &h, gnl_entry) {
list_del_init(&fcport->gnl_entry);
spin_lock(&vha->hw->tgt.sess_lock);
fcport->flags &= ~(FCF_ASYNC_SENT | FCF_ASYNC_ACTIVE);
spin_unlock(&vha->hw->tgt.sess_lock);
ea.fcport = fcport;

qla2x00_fcport_event_handler(vha, &ea);
}
spin_unlock_irqrestore(&vha->gnl.fcports_lock, flags);

spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
/* create new fcport if fw has knowledge of new sessions */
for (i = 0; i < n; i++) {
port_id_t id;
Expand Down Expand Up @@ -710,18 +713,21 @@ int qla24xx_async_gnl(struct scsi_qla_host *vha, fc_port_t *fcport)
ql_dbg(ql_dbg_disc, vha, 0x20d9,
"Async-gnlist WWPN %8phC \n", fcport->port_name);

spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
spin_lock_irqsave(&vha->gnl.fcports_lock, flags);
if (!list_empty(&fcport->gnl_entry)) {
spin_unlock_irqrestore(&vha->gnl.fcports_lock, flags);
rval = QLA_SUCCESS;
goto done;
}

spin_lock(&vha->hw->tgt.sess_lock);
fcport->disc_state = DSC_GNL;
fcport->last_rscn_gen = fcport->rscn_gen;
fcport->last_login_gen = fcport->login_gen;
spin_unlock(&vha->hw->tgt.sess_lock);

list_add_tail(&fcport->gnl_entry, &vha->gnl.fcports);
if (vha->gnl.sent) {
spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
return QLA_SUCCESS;
}
vha->gnl.sent = 1;
spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
spin_unlock_irqrestore(&vha->gnl.fcports_lock, flags);

sp = qla2x00_get_sp(vha, fcport, GFP_KERNEL);
if (!sp)
Expand Down
7 changes: 6 additions & 1 deletion drivers/scsi/qla2xxx/qla_os.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4577,6 +4577,7 @@ struct scsi_qla_host *qla2x00_create_host(struct scsi_host_template *sht,

spin_lock_init(&vha->work_lock);
spin_lock_init(&vha->cmd_list_lock);
spin_lock_init(&vha->gnl.fcports_lock);
init_waitqueue_head(&vha->fcport_waitQ);
init_waitqueue_head(&vha->vref_waitq);

Expand Down Expand Up @@ -4877,6 +4878,8 @@ void qla24xx_create_new_sess(struct scsi_qla_host *vha, struct qla_work_evt *e)
}
qlt_plogi_ack_unref(vha, pla);
} else {
fc_port_t *dfcp = NULL;

spin_lock_irqsave(&vha->hw->tgt.sess_lock, flags);
tfcp = qla2x00_find_fcport_by_nportid(vha,
&e->u.new_sess.id, 1);
Expand All @@ -4899,11 +4902,13 @@ void qla24xx_create_new_sess(struct scsi_qla_host *vha, struct qla_work_evt *e)
default:
fcport->login_pause = 1;
tfcp->conflict = fcport;
qlt_schedule_sess_for_deletion(tfcp);
dfcp = tfcp;
break;
}
}
spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
if (dfcp)
qlt_schedule_sess_for_deletion(tfcp);

wwn = wwn_to_u64(fcport->node_name);

Expand Down
17 changes: 6 additions & 11 deletions drivers/scsi/qla2xxx/qla_target.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1224,10 +1224,10 @@ static void qla24xx_chk_fcp_state(struct fc_port *sess)
}
}

/* ha->tgt.sess_lock supposed to be held on entry */
void qlt_schedule_sess_for_deletion(struct fc_port *sess)
{
struct qla_tgt *tgt = sess->tgt;
struct qla_hw_data *ha = sess->vha->hw;
unsigned long flags;

if (sess->disc_state == DSC_DELETE_PEND)
Expand All @@ -1244,16 +1244,16 @@ void qlt_schedule_sess_for_deletion(struct fc_port *sess)
return;
}

spin_lock_irqsave(&ha->tgt.sess_lock, flags);
if (sess->deleted == QLA_SESS_DELETED)
sess->logout_on_delete = 0;

spin_lock_irqsave(&sess->vha->work_lock, flags);
if (sess->deleted == QLA_SESS_DELETION_IN_PROGRESS) {
spin_unlock_irqrestore(&sess->vha->work_lock, flags);
spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
return;
}
sess->deleted = QLA_SESS_DELETION_IN_PROGRESS;
spin_unlock_irqrestore(&sess->vha->work_lock, flags);
spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);

sess->disc_state = DSC_DELETE_PEND;

Expand All @@ -1262,13 +1262,10 @@ void qlt_schedule_sess_for_deletion(struct fc_port *sess)
ql_dbg(ql_dbg_tgt, sess->vha, 0xe001,
"Scheduling sess %p for deletion\n", sess);

/* use cancel to push work element through before re-queue */
cancel_work_sync(&sess->del_work);
INIT_WORK(&sess->del_work, qla24xx_delete_sess_fn);
queue_work(sess->vha->hw->wq, &sess->del_work);
WARN_ON(!queue_work(sess->vha->hw->wq, &sess->del_work));
}

/* ha->tgt.sess_lock supposed to be held on entry */
static void qlt_clear_tgt_db(struct qla_tgt *tgt)
{
struct fc_port *sess;
Expand Down Expand Up @@ -1451,8 +1448,8 @@ qlt_fc_port_deleted(struct scsi_qla_host *vha, fc_port_t *fcport, int max_gen)
ql_dbg(ql_dbg_tgt_mgt, vha, 0xf008, "qla_tgt_fc_port_deleted %p", sess);

sess->local = 1;
qlt_schedule_sess_for_deletion(sess);
spin_unlock_irqrestore(&vha->hw->tgt.sess_lock, flags);
qlt_schedule_sess_for_deletion(sess);
}

static inline int test_tgt_sess_count(struct qla_tgt *tgt)
Expand Down Expand Up @@ -1512,10 +1509,8 @@ int qlt_stop_phase1(struct qla_tgt *tgt)
* Lock is needed, because we still can get an incoming packet.
*/
mutex_lock(&vha->vha_tgt.tgt_mutex);
spin_lock_irqsave(&ha->tgt.sess_lock, flags);
tgt->tgt_stop = 1;
qlt_clear_tgt_db(tgt);
spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
mutex_unlock(&vha->vha_tgt.tgt_mutex);
mutex_unlock(&qla_tgt_mutex);

Expand Down

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