qla_target: don't delete changed nacls

The code is currently riddled with "drop the hardware_lock to avoid a
deadlock" bugs that expose races.  One of those races seems to expose a
valid warning in tcm_qla2xxx_clear_nacl_from_fcport_map.  Add some
bandaid to it.

Signed-off-by: Joern Engel <joern@logfs.org>
Cc: <stable@vger.kernel.org> # v3.5+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
index e2beab962096..4747d2c66024 100644
--- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c
+++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
@@ -757,7 +757,16 @@ static void tcm_qla2xxx_clear_nacl_from_fcport_map(struct qla_tgt_sess *sess)
         pr_debug("fc_rport domain: port_id 0x%06x\n", nacl->nport_id);
 
         node = btree_remove32(&lport->lport_fcport_map, nacl->nport_id);
-        WARN_ON(node && (node != se_nacl));
+        if (WARN_ON(node && (node != se_nacl))) {
+                /*
+                 * The nacl no longer matches what we think it should be.
+                 * Most likely a new dynamic acl has been added while
+                 * someone dropped the hardware lock.  It clearly is a
+                 * bug elsewhere, but this bit can't make things worse.
+                 */
+                btree_insert32(&lport->lport_fcport_map, nacl->nport_id,
+                               node, GFP_ATOMIC);
+        }
 
         pr_debug("Removed from fcport_map: %p for WWNN: 0x%016LX, port_id: 0x%06x\n",
             se_nacl, nacl->nport_wwnn, nacl->nport_id);