From: Quinn Tran <quinn.t...@cavium.com>
The main lock that needs to be held for CMD or TMR submission
to upper layer is the sess_lock. The sess_lock is used to
serialize cmd submission and session deletion. The addition
of hardware_lock being held is not necessary. This patch removes
hardware_lock dependency from CMD/TMR submission.
Use hardware_lock only for error response in this case.
Path1
CPU0 CPU1
---- ----
lock(&(&ha->tgt.sess_lock)->rlock);
lock(&(&ha->hardware_lock)->rlock);
lock(&(&ha->tgt.sess_lock)->rlock);
lock(&(&ha->hardware_lock)->rlock);
Path2/deadlock
*** DEADLOCK ***
Call Trace:
dump_stack+0x85/0xc2
print_circular_bug+0x1e3/0x250
__lock_acquire+0x1425/0x1620
lock_acquire+0xbf/0x210
_raw_spin_lock_irqsave+0x53/0x70
qlt_sess_work_fn+0x21d/0x480 [qla2xxx]
process_one_work+0x1f4/0x6e0
Cc: <sta...@vger.kernel.org>
Cc: Bart Van Assche <bart.vanass...@sandisk.com>
Reported-by: Bart Van Assche <bart.vanass...@sandisk.com>
Signed-off-by: Quinn Tran <quinn.t...@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madh...@cavium.com>
---
drivers/scsi/qla2xxx/qla_target.c | 41 +++++++++++++++++----------------------
1 file changed, 18 insertions(+), 23 deletions(-)
diff --git a/drivers/scsi/qla2xxx/qla_target.c
b/drivers/scsi/qla2xxx/qla_target.c
index a78c3e9bcb57..989f931af156 100644
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -5727,30 +5727,23 @@ static void qlt_abort_work(struct qla_tgt *tgt,
}
}
- spin_lock_irqsave(&ha->hardware_lock, flags);
-
- if (tgt->tgt_stop)
- goto out_term;
-
rc = __qlt_24xx_handle_abts(vha, &prm->abts, sess);
+ ha->tgt.tgt_ops->put_sess(sess);
+ spin_unlock_irqrestore(&ha->tgt.sess_lock, flags2);
+
if (rc != 0)
goto out_term;
- spin_unlock_irqrestore(&ha->hardware_lock, flags);
- if (sess)
- ha->tgt.tgt_ops->put_sess(sess);
- spin_unlock_irqrestore(&ha->tgt.sess_lock, flags2);
return;
out_term2:
- spin_lock_irqsave(&ha->hardware_lock, flags);
+ if (sess)
+ ha->tgt.tgt_ops->put_sess(sess);
+ spin_unlock_irqrestore(&ha->tgt.sess_lock, flags2);
out_term:
+ spin_lock_irqsave(&ha->hardware_lock, flags);
qlt_24xx_send_abts_resp(vha, &prm->abts, FCP_TMF_REJECTED, false);
spin_unlock_irqrestore(&ha->hardware_lock, flags);
-
- if (sess)
- ha->tgt.tgt_ops->put_sess(sess);
- spin_unlock_irqrestore(&ha->tgt.sess_lock, flags2);
}
static void qlt_tmr_work(struct qla_tgt *tgt,
@@ -5770,7 +5763,7 @@ static void qlt_tmr_work(struct qla_tgt *tgt,
spin_lock_irqsave(&ha->tgt.sess_lock, flags);
if (tgt->tgt_stop)
- goto out_term;
+ goto out_term2;
s_id = prm->tm_iocb2.u.isp24.fcp_hdr.s_id;
sess = ha->tgt.tgt_ops->find_sess_by_s_id(vha, s_id);
@@ -5782,11 +5775,11 @@ static void qlt_tmr_work(struct qla_tgt *tgt,
spin_lock_irqsave(&ha->tgt.sess_lock, flags);
if (!sess)
- goto out_term;
+ goto out_term2;
} else {
if (sess->deleted) {
sess = NULL;
- goto out_term;
+ goto out_term2;
}
if (!kref_get_unless_zero(&sess->sess_kref)) {
@@ -5794,7 +5787,7 @@ static void qlt_tmr_work(struct qla_tgt *tgt,
"%s: kref_get fail %8phC\n",
__func__, sess->port_name);
sess = NULL;
- goto out_term;
+ goto out_term2;
}
}
@@ -5804,17 +5797,19 @@ static void qlt_tmr_work(struct qla_tgt *tgt,
unpacked_lun = scsilun_to_int((struct scsi_lun *)&lun);
rc = qlt_issue_task_mgmt(sess, unpacked_lun, fn, iocb, 0);
- if (rc != 0)
- goto out_term;
-
ha->tgt.tgt_ops->put_sess(sess);
spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
+
+ if (rc != 0)
+ goto out_term;
return;
+out_term2:
+ if (sess)
+ ha->tgt.tgt_ops->put_sess(sess);
+ spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
out_term:
qlt_send_term_exchange(vha, NULL, &prm->tm_iocb2, 1, 0);
- ha->tgt.tgt_ops->put_sess(sess);
- spin_unlock_irqrestore(&ha->tgt.sess_lock, flags);
}
static void qlt_sess_work_fn(struct work_struct *work)
--
2.12.0
