From: Brad Peters <bpeters@redhat.com>
Date: Thu, 10 Apr 2008 16:45:34 -0400
Subject: [ppc64] eHEA: fixes receive packet handling
Message-id: 47FE7C6E.6070806@redhat.com
O-Subject: Re: [RHEL 5.2 patch] [Regression] eHEA driver fixes receive packet handling and cleanup during unrecoverable error
Bugzilla: 441364

RHBZ#:
======
https://bugzilla.redhat.com/show_bug.cgi?id=441364

Description:
===========
The ehea driver may crash during DLPAR Memory Add operations causing a
kernel
panic. The reason is a bug in the driver's receive packet handling.
Additionally a driver weakness on the send side can cause an interface to
drop in an unrecoverable error state.

RHEL Version Found:
================
RHEL 5.2

kABI Status:
============
No symbols were harmed.

Upstream Status:
================
Upstream in :
http://lkml.org/lkml/2008/4/4/170

Test Status:
============
Tested using script which does a mem add dlpar on RHEL5.2 snapshot2 on P6
IH with a HEA. The test is to add mem, sleep for a few minutes, add mem
again, and so forth.
The script is run repeatedly (5+ times). Each time, the system drops into
xmon in
less than 1 hour(the sleep time between each dlpar is 6m, so it's about 10
mem
add dlpar in 1 hour).

Test passed with patch.

===============================================================

Brad Peters 1-978-392-1000 x 23183
IBM on-site partner.
---------------

Acked-by: David Howells <dhowells@redhat.com>

diff --git a/drivers/net/ehea/ehea.h b/drivers/net/ehea/ehea.h
index 985d6e8..1ff9023 100644
--- a/drivers/net/ehea/ehea.h
+++ b/drivers/net/ehea/ehea.h
@@ -41,7 +41,7 @@
 #include "inet_lro.h"
 
 #define DRV_NAME	"ehea"
-#define DRV_VERSION	"EHEA_0076-03"
+#define DRV_VERSION	"EHEA_0076-05"
 
 /* eHEA capability flags */
 #define DLPAR_PORT_ADD_REM 1
@@ -372,6 +372,7 @@ struct ehea_port_res {
 	struct ehea_q_skb_arr rq2_skba;
 	struct ehea_q_skb_arr rq3_skba;
 	struct ehea_q_skb_arr sq_skba;
+	int sq_skba_size;
 	spinlock_t netif_queue;
 	int queue_stopped;
 	int swqe_refill_th;
diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
index 59cd37c..eeba0ef 100644
--- a/drivers/net/ehea/ehea_main.c
+++ b/drivers/net/ehea/ehea_main.c
@@ -184,7 +184,12 @@ static void ehea_refill_rq1(struct ehea_port_res *pr, int index, int nr_of_wqes)
 	pr->rq1_skba.os_skbs = 0;
 
 	if (unlikely(test_bit(__EHEA_STOP_XFER, &ehea_driver_flags))) {
-		pr->rq1_skba.index = index;
+/*
+ * The parameter "index" is not valid in case ehea_refill_rq1() is
+ * called with (nr_of_wqes=0). Thus "rq1_skba.index" must not be updated.
+ */
+		if (nr_of_wqes > 0)
+			pr->rq1_skba.index = index;
 		pr->rq1_skba.os_skbs = fill_wqes;
 		return;
 	}
@@ -1305,7 +1310,9 @@ static int ehea_init_port_res(struct ehea_port *port, struct ehea_port_res *pr,
 			  init_attr->act_nr_rwqes_rq2,
 			  init_attr->act_nr_rwqes_rq3);
 
-	ret = ehea_init_q_skba(&pr->sq_skba, init_attr->act_nr_send_wqes + 1);
+	pr->sq_skba_size = init_attr->act_nr_send_wqes + 1;
+
+	ret = ehea_init_q_skba(&pr->sq_skba, pr->sq_skba_size);
 	ret |= ehea_init_q_skba(&pr->rq1_skba, init_attr->act_nr_rwqes_rq1 + 1);
 	ret |= ehea_init_q_skba(&pr->rq2_skba, init_attr->act_nr_rwqes_rq2 + 1);
 	ret |= ehea_init_q_skba(&pr->rq3_skba, init_attr->act_nr_rwqes_rq3 + 1);
@@ -2419,6 +2426,31 @@ void ehea_purge_sq(struct ehea_qp *orig_qp)
 	}
 }
 
+/*
+ * ehea_flush_sq() ensures that all elements on the send queues
+ * have been processed by the HW before the HW queues are stopped.
+ * After about 100ms the function will return control to the caller
+ * function in any case.
+ */
+
+void ehea_flush_sq(struct ehea_port *port)
+{
+	int i;
+
+	for (i = 0; i < port->num_def_qps + port->num_add_tx_qps; i++) {
+		struct ehea_port_res *pr = &port->port_res[i];
+		int swqe_max = pr->sq_skba_size - 2 - pr->swqe_ll_count;
+		int k = 0;
+		while (atomic_read(&pr->swqe_avail) < swqe_max) {
+			msleep(5);
+			if (++k == 20) {
+				WARN_ON(1);
+				break;
+			}
+		}
+	}
+}
+
 int ehea_stop_qps(struct net_device *dev)
 {
 	struct ehea_port *port = netdev_priv(dev);
@@ -2657,6 +2689,7 @@ static void ehea_rereg_mrs(void *data)
 					if (dev->flags & IFF_UP) {
 						down(&port->port_lock);
 						netif_stop_queue(dev);
+						ehea_flush_sq(port);
 						ret = ehea_stop_qps(dev);
 						if (ret) {
 							up(&port->port_lock);