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

[Juliet Kim]

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 <juli...@linux.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