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>

1 files changed, 14 insertions, 2 deletions

diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
index 2eb97d7e8d12..ea3eaef3f81b 100644
--- 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);