From: Michal Kalderon <Michal.Kalderon@cavium.com>
Date: Wed, 16 May 2018 14:44:40 +0300
Subject: qed: Fix LL2 race during connection terminate
Patch-mainline: v4.18-rc1
Git-commit: fc16f56b7bfd5bfe812ba2cd3a4c8943977e8306
References: bsc#1086314 FATE#324886 bsc#1086313 FATE#324885 bsc#1086301 FATE#3248881

Stress on qedi/qedr load unload lead to list_del corruption.
This is due to ll2 connection terminate freeing resources without
verifying that no more ll2 processing will occur.

This patch unregisters the ll2 status block before terminating
the connection to assure this race does not occur.

Fixes: 1d6cff4fca4366 ("qed: Add iSCSI out of order packet handling")
Signed-off-by: Ariel Elior <Ariel.Elior@cavium.com>
Signed-off-by: Michal Kalderon <Michal.Kalderon@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/qlogic/qed/qed_ll2.c |   24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

--- a/drivers/net/ethernet/qlogic/qed/qed_ll2.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_ll2.c
@@ -829,6 +829,9 @@ static int qed_ll2_lb_rxq_completion(str
 	struct qed_ll2_info *p_ll2_conn = (struct qed_ll2_info *)p_cookie;
 	int rc;
 
+	if (!QED_LL2_RX_REGISTERED(p_ll2_conn))
+		return 0;
+
 	rc = qed_ll2_lb_rxq_handler(p_hwfn, p_ll2_conn);
 	if (rc)
 		return rc;
@@ -849,6 +852,9 @@ static int qed_ll2_lb_txq_completion(str
 	u16 new_idx = 0, num_bds = 0;
 	int rc;
 
+	if (!QED_LL2_TX_REGISTERED(p_ll2_conn))
+		return 0;
+
 	new_idx = le16_to_cpu(*p_tx->p_fw_cons);
 	num_bds = ((s16)new_idx - (s16)p_tx->bds_idx);
 
@@ -1915,17 +1921,25 @@ int qed_ll2_terminate_connection(void *c
 
 	/* Stop Tx & Rx of connection, if needed */
 	if (QED_LL2_TX_REGISTERED(p_ll2_conn)) {
+		p_ll2_conn->tx_queue.b_cb_registred = false;
+		smp_wmb(); /* Make sure this is seen by ll2_lb_rxq_completion */
 		rc = qed_sp_ll2_tx_queue_stop(p_hwfn, p_ll2_conn);
 		if (rc)
 			goto out;
+
 		qed_ll2_txq_flush(p_hwfn, connection_handle);
+		qed_int_unregister_cb(p_hwfn, p_ll2_conn->tx_queue.tx_sb_index);
 	}
 
 	if (QED_LL2_RX_REGISTERED(p_ll2_conn)) {
+		p_ll2_conn->rx_queue.b_cb_registred = false;
+		smp_wmb(); /* Make sure this is seen by ll2_lb_rxq_completion */
 		rc = qed_sp_ll2_rx_queue_stop(p_hwfn, p_ll2_conn);
 		if (rc)
 			goto out;
+
 		qed_ll2_rxq_flush(p_hwfn, connection_handle);
+		qed_int_unregister_cb(p_hwfn, p_ll2_conn->rx_queue.rx_sb_index);
 	}
 
 	if (p_ll2_conn->input.conn_type == QED_LL2_TYPE_OOO)
@@ -1974,16 +1988,6 @@ void qed_ll2_release_connection(void *cx
 	if (!p_ll2_conn)
 		return;
 
-	if (QED_LL2_RX_REGISTERED(p_ll2_conn)) {
-		p_ll2_conn->rx_queue.b_cb_registred = false;
-		qed_int_unregister_cb(p_hwfn, p_ll2_conn->rx_queue.rx_sb_index);
-	}
-
-	if (QED_LL2_TX_REGISTERED(p_ll2_conn)) {
-		p_ll2_conn->tx_queue.b_cb_registred = false;
-		qed_int_unregister_cb(p_hwfn, p_ll2_conn->tx_queue.tx_sb_index);
-	}
-
 	kfree(p_ll2_conn->tx_queue.descq_mem);
 	qed_chain_free(p_hwfn->cdev, &p_ll2_conn->tx_queue.txq_chain);