[PATCH] qla2xxx: Protect access to qpair members with qpair->qp_lock

[Johannes Thumshirn]

In qla2xx_start_scsi_mq() and qla2xx_dif_start_scsi_mq() we grab the
qpair->qp_lock but do access members of the qpair before having the lock.
Re-order the locking sequence to have all read and write access to qpair
members under the qpair->qp_lock.

Signed-off-by: Johannes Thumshirn <jthumsh...@suse.de>
---
 drivers/scsi/qla2xxx/qla_iocb.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index 8404f17f3c6c..425ca1646a9a 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -1770,10 +1770,6 @@ qla2xxx_start_scsi_mq(srb_t *sp)
        struct qla_hw_data *ha = vha->hw;
        struct qla_qpair *qpair = sp->qpair;
 
-       /* Setup qpair pointers */
-       rsp = qpair->rsp;
-       req = qpair->req;
-
        /* So we know we haven't pci_map'ed anything yet */
        tot_dsds = 0;
 
@@ -1788,6 +1784,10 @@ qla2xxx_start_scsi_mq(srb_t *sp)
        /* Acquire qpair specific lock */
        spin_lock_irqsave(&qpair->qp_lock, flags);
 
+       /* Setup qpair pointers */
+       rsp = qpair->rsp;
+       req = qpair->req;
+
        /* Check for room in outstanding command list. */
        handle = req->current_outstanding_cmd;
        for (index = 1; index < req->num_outstanding_cmds; index++) {
@@ -1924,24 +1924,33 @@ qla2xxx_dif_start_scsi_mq(srb_t *sp)
 
 #define QDSS_GOT_Q_SPACE       BIT_0
 
+       /* Acquire ring specific lock */
+       spin_lock_irqsave(&qpair->qp_lock, flags);
+
        /* Check for host side state */
        if (!qpair->online) {
                cmd->result = DID_NO_CONNECT << 16;
+               spin_unlock_irqrestore(&qpair->qp_lock, flags);
                return QLA_INTERFACE_ERROR;
        }
 
        if (!qpair->difdix_supported &&
                scsi_get_prot_op(cmd) != SCSI_PROT_NORMAL) {
                cmd->result = DID_NO_CONNECT << 16;
+               spin_unlock_irqrestore(&qpair->qp_lock, flags);
                return QLA_INTERFACE_ERROR;
        }
 
+       spin_unlock_irqrestore(&qpair->qp_lock, flags);
+
        /* Only process protection or >16 cdb in this routine */
        if (scsi_get_prot_op(cmd) == SCSI_PROT_NORMAL) {
                if (cmd->cmd_len <= 16)
                        return qla2xxx_start_scsi_mq(sp);
        }
 
+       spin_lock_irqsave(&qpair->qp_lock, flags);
+
        /* Setup qpair pointers */
        rsp = qpair->rsp;
        req = qpair->req;
@@ -1957,9 +1966,6 @@ qla2xxx_dif_start_scsi_mq(srb_t *sp)
                vha->marker_needed = 0;
        }
 
-       /* Acquire ring specific lock */
-       spin_lock_irqsave(&qpair->qp_lock, flags);
-
        /* Check for room in outstanding command list. */
        handle = req->current_outstanding_cmd;
        for (index = 1; index < req->num_outstanding_cmds; index++) {
-- 
2.12.3