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

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Message-Id: <20190820213120.19880-2-julietk@linux.vnet.ibm.com>
Date:   Tue, 20 Aug 2019 17:31:20 -0400
From:   Juliet Kim <julietk@...ux.vnet.ibm.com>
To:     netdev@...r.kernel.org
Cc:     julietk@...ux.vnet.ibm.com, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH 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 | 19 ++++++++++++++++++-
 drivers/net/ethernet/ibm/ibmvnic.h |  3 +++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index a3e2fbb9c5db..7db7a44eeeb9 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2049,6 +2049,13 @@ 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);
@@ -2085,6 +2092,15 @@ 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)
 {
@@ -2137,7 +2153,6 @@ 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);
 
@@ -4910,6 +4925,8 @@ 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 70bd286f8932..0e1fadbcffc0 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -38,6 +38,8 @@
 #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"
@@ -1076,6 +1078,7 @@ 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