netdev - [PATCH v2 2/2] net/ibmvnic: prevent more than one thread from running in reset

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Date:   Tue, 17 Sep 2019 10:52:49 -0400
From:   Juliet Kim <julietk@...ux.vnet.ibm.com>
To:     netdev@...r.kernel.org
Cc:     julietk@...ux.vnet.ibm.com, tlfalcon@...ux.vnet.ibm.com,
        linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 2/2] net/ibmvnic: prevent more than one thread from running in reset

The current code allows more than one thread to run in reset. This can 
corrupt struct adapter data. Check adapter->resetting before performing 
a reset, if there is another reset running delay (100 msec) before trying 
again.

Signed-off-by: Juliet Kim <julietk@...ux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 23 ++++++++++++++++++++++-
 drivers/net/ethernet/ibm/ibmvnic.h |  3 +++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index fc760c1eb0b0..d3ebf4caa09c 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2054,6 +2054,13 @@ static void __ibmvnic_reset(struct work_struct *work)
 
 	adapter = container_of(work, struct ibmvnic_adapter, ibmvnic_reset);
 
+	if (adapter->resetting) {
+		schedule_delayed_work(&adapter->ibmvnic_delayed_reset,
+				      IBMVNIC_RESET_DELAY);
+		return;
+	}
+
+	adapter->resetting = true;
 	reset_state = adapter->state;
 
 	rwi = get_next_rwi(adapter);
@@ -2094,6 +2101,10 @@ static void __ibmvnic_reset(struct work_struct *work)
 			break;
 
 		rwi = get_next_rwi(adapter);
+
+		if (rwi && (rwi->reset_reason == VNIC_RESET_FAILOVER ||
+			    rwi->reset_reason == VNIC_RESET_MOBILITY))
+			adapter->force_reset_recovery = true;
 	}
 
 	if (adapter->wait_for_reset) {
@@ -2109,6 +2120,15 @@ static void __ibmvnic_reset(struct work_struct *work)
 	adapter->resetting = false;
 }
 
+static void __ibmvnic_delayed_reset(struct work_struct *work)
+{
+	struct ibmvnic_adapter *adapter;
+
+	adapter = container_of(work, struct ibmvnic_adapter,
+			       ibmvnic_delayed_reset.work);
+	__ibmvnic_reset(&adapter->ibmvnic_reset);
+}
+
 static int ibmvnic_reset(struct ibmvnic_adapter *adapter,
 			 enum ibmvnic_reset_reason reason)
 {
@@ -2161,7 +2181,6 @@ static int ibmvnic_reset(struct ibmvnic_adapter *adapter,
 	rwi->reset_reason = reason;
 	list_add_tail(&rwi->list, &adapter->rwi_list);
 	spin_unlock_irqrestore(&adapter->rwi_lock, flags);
-	adapter->resetting = true;
 	netdev_dbg(adapter->netdev, "Scheduling reset (reason %d)\n", reason);
 	schedule_work(&adapter->ibmvnic_reset);
 
@@ -4932,6 +4951,8 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	spin_lock_init(&adapter->stats_lock);
 
 	INIT_WORK(&adapter->ibmvnic_reset, __ibmvnic_reset);
+	INIT_DELAYED_WORK(&adapter->ibmvnic_delayed_reset,
+			  __ibmvnic_delayed_reset);
 	INIT_LIST_HEAD(&adapter->rwi_list);
 	spin_lock_init(&adapter->rwi_lock);
 	init_completion(&adapter->init_done);
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index 9d3d35cc91d6..4f4651d92cc1 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -39,6 +39,8 @@
 #define IBMVNIC_MAX_LTB_SIZE ((1 << (MAX_ORDER - 1)) * PAGE_SIZE)
 #define IBMVNIC_BUFFER_HLEN 500
 
+#define IBMVNIC_RESET_DELAY 100
+
 static const char ibmvnic_priv_flags[][ETH_GSTRING_LEN] = {
 #define IBMVNIC_USE_SERVER_MAXES 0x1
 	"use-server-maxes"
@@ -1077,6 +1079,7 @@ struct ibmvnic_adapter {
 	spinlock_t rwi_lock;
 	struct list_head rwi_list;
 	struct work_struct ibmvnic_reset;
+	struct delayed_work ibmvnic_delayed_reset;
 	bool resetting;
 	bool napi_enabled, from_passive_init;
 
-- 
2.16.4