qla2xxx: Fix qlt_lport_register base_vha callback race

This patch closes a race between qlt_lport_register() and
tcm_qla2xxx callback logic by holding qla_tgt_mutex before
making the callback.

In order for this to work, the qlt_add_target() and
qlt_remove_target() code has been changed to avoid the
accessing qla_tgt_mutex + list_[add,del] for NPIV enabled
ports.

This bug introduced in v3.14-rc1 code with commit 49a47f2.

Cc: Sawan Chandak <sawan.chandak@qlogic.com>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Saurav Kashyap <saurav.kashyap@qlogic.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
index 2eb97d7..ea3eaef 100644 (file)
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -4181,6 +4181,9 @@ int qlt_add_target(struct qla_hw_data *ha, struct scsi_qla_host *base_vha)
        tgt->datasegs_per_cmd = QLA_TGT_DATASEGS_PER_CMD_24XX;
        tgt->datasegs_per_cont = QLA_TGT_DATASEGS_PER_CONT_24XX;
 
+       if (base_vha->fc_vport)
+               return 0;
+
        mutex_lock(&qla_tgt_mutex);
        list_add_tail(&tgt->tgt_list_entry, &qla_tgt_glist);
        mutex_unlock(&qla_tgt_mutex);
@@ -4194,6 +4197,10 @@ int qlt_remove_target(struct qla_hw_data *ha, struct scsi_qla_host *vha)
        if (!vha->vha_tgt.qla_tgt)
                return 0;
 
+       if (vha->fc_vport) {
+               qlt_release(vha->vha_tgt.qla_tgt);
+               return 0;
+       }
        mutex_lock(&qla_tgt_mutex);
        list_del(&vha->vha_tgt.qla_tgt->tgt_list_entry);
        mutex_unlock(&qla_tgt_mutex);
@@ -4265,6 +4272,12 @@ int qlt_lport_register(void *target_lport_ptr, u64 phys_wwpn,
                        spin_unlock_irqrestore(&ha->hardware_lock, flags);
                        continue;
                }
+               if (tgt->tgt_stop) {
+                       pr_debug("MODE_TARGET in shutdown on qla2xxx(%d)\n",
+                                host->host_no);
+                       spin_unlock_irqrestore(&ha->hardware_lock, flags);
+                       continue;
+               }
                spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
                if (!scsi_host_get(host)) {
@@ -4279,12 +4292,11 @@ int qlt_lport_register(void *target_lport_ptr, u64 phys_wwpn,
                        scsi_host_put(host);
                        continue;
                }
-               mutex_unlock(&qla_tgt_mutex);
-
                rc = (*callback)(vha, target_lport_ptr, npiv_wwpn, npiv_wwnn);
                if (rc != 0)
                        scsi_host_put(host);
 
+               mutex_unlock(&qla_tgt_mutex);
                return rc;
        }
        mutex_unlock(&qla_tgt_mutex);