[PATCH 3.12 111/206] qla_target: don't delete changed nacls

From: Jiri Slaby
Date: Tue Nov 18 2014 - 09:45:10 EST

From: Joern Engel <joern@xxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


commit f4c24db1b7ad0ce84409e15744d26c6f86a96840 upstream.

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@xxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
drivers/scsi/qla2xxx/tcm_qla2xxx.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
index f85b9e5c1f05..80a1f9f40aac 100644
--- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c
+++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
@@ -740,7 +740,16 @@ 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);

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