be2net: fix tx completion polling

In tx/mcc polling, napi_complete() is being incorrectly called
before reaping tx completions. This can cause tx compl processing
to be scheduled on another cpu concurrently which can result in a panic.
This if fixed by calling napi complete() after tx/mcc compl processing
but before re-enabling interrupts (via a cq notify).

Signed-off-by: Sathya Perla <sathyap@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 37 insertions, 38 deletions

diff --git a/drivers/net/benet/be_cmds.c b/drivers/net/benet/be_cmds.c
index c8a2bacb1d13..4b1f80519ca4 100644
--- a/drivers/net/benet/be_cmds.c
+++ b/drivers/net/benet/be_cmds.c
@@ -119,10 +119,10 @@ void be_async_mcc_disable(struct be_adapter *adapter)
         adapter->mcc_obj.rearm_cq = false;
 }
 
-int be_process_mcc(struct be_adapter *adapter)
+int be_process_mcc(struct be_adapter *adapter, int *status)
 {
         struct be_mcc_compl *compl;
-        int num = 0, status = 0;
+        int num = 0;
         struct be_mcc_obj *mcc_obj = &adapter->mcc_obj;
 
         spin_lock_bh(&adapter->mcc_cq_lock);
@@ -135,31 +135,31 @@ int be_process_mcc(struct be_adapter *adapter)
                         be_async_link_state_process(adapter,
                                 (struct be_async_event_link_state *) compl);
                 } else if (compl->flags & CQE_FLAGS_COMPLETED_MASK) {
-                                status = be_mcc_compl_process(adapter, compl);
+                                *status = be_mcc_compl_process(adapter, compl);
                                 atomic_dec(&mcc_obj->q.used);
                 }
                 be_mcc_compl_use(compl);
                 num++;
         }
 
-        if (num)
-                be_cq_notify(adapter, mcc_obj->cq.id, mcc_obj->rearm_cq, num);
-
         spin_unlock_bh(&adapter->mcc_cq_lock);
-        return status;
+        return num;
 }
 
 /* Wait till no more pending mcc requests are present */
 static int be_mcc_wait_compl(struct be_adapter *adapter)
 {
 #define mcc_timeout             120000 /* 12s timeout */
-        int i, status;
+        int i, num, status = 0;
+        struct be_mcc_obj *mcc_obj = &adapter->mcc_obj;
+
         for (i = 0; i < mcc_timeout; i++) {
-                status = be_process_mcc(adapter);
-                if (status)
-                        return status;
+                num = be_process_mcc(adapter, &status);
+                if (num)
+                        be_cq_notify(adapter, mcc_obj->cq.id,
+                                mcc_obj->rearm_cq, num);
 
-                if (atomic_read(&adapter->mcc_obj.q.used) == 0)
+                if (atomic_read(&mcc_obj->q.used) == 0)
                         break;
                 udelay(100);
         }
@@ -167,7 +167,7 @@ static int be_mcc_wait_compl(struct be_adapter *adapter)
                 dev_err(&adapter->pdev->dev, "mccq poll timed out\n");
                 return -1;
         }
-        return 0;
+        return status;
 }
 
 /* Notify MCC requests and wait for completion */
diff --git a/drivers/net/benet/be_cmds.h b/drivers/net/benet/be_cmds.h
index 728b0d736929..cce61f9a3714 100644
--- a/drivers/net/benet/be_cmds.h
+++ b/drivers/net/benet/be_cmds.h
@@ -920,7 +920,7 @@ extern int be_cmd_get_flow_control(struct be_adapter *adapter,
 extern int be_cmd_query_fw_cfg(struct be_adapter *adapter,
                         u32 *port_num, u32 *cap);
 extern int be_cmd_reset_function(struct be_adapter *adapter);
-extern int be_process_mcc(struct be_adapter *adapter);
+extern int be_process_mcc(struct be_adapter *adapter, int *status);
 extern int be_cmd_set_beacon_state(struct be_adapter *adapter,
                         u8 port_num, u8 beacon, u8 status, u8 state);
 extern int be_cmd_get_beacon_state(struct be_adapter *adapter,
diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index 27ccdd80257b..a703ed8e24fe 100644
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -583,7 +583,7 @@ static void be_set_multicast_list(struct net_device *netdev)
         }
 
         be_cmd_multicast_set(adapter, adapter->if_handle, netdev,
-                        &adapter->mc_cmd_mem);
+                &adapter->mc_cmd_mem);
 done:
         return;
 }
@@ -1469,23 +1469,38 @@ int be_poll_rx(struct napi_struct *napi, int budget)
         return work_done;
 }
 
-void be_process_tx(struct be_adapter *adapter)
+/* As TX and MCC share the same EQ check for both TX and MCC completions.
+ * For TX/MCC we don't honour budget; consume everything
+ */
+static int be_poll_tx_mcc(struct napi_struct *napi, int budget)
 {
+        struct be_eq_obj *tx_eq = container_of(napi, struct be_eq_obj, napi);
+        struct be_adapter *adapter =
+                container_of(tx_eq, struct be_adapter, tx_eq);
         struct be_queue_info *txq = &adapter->tx_obj.q;
         struct be_queue_info *tx_cq = &adapter->tx_obj.cq;
         struct be_eth_tx_compl *txcp;
-        u32 num_cmpl = 0;
+        int tx_compl = 0, mcc_compl, status = 0;
         u16 end_idx;
 
         while ((txcp = be_tx_compl_get(tx_cq))) {
                 end_idx = AMAP_GET_BITS(struct amap_eth_tx_compl,
-                                        wrb_index, txcp);
+                                wrb_index, txcp);
                 be_tx_compl_process(adapter, end_idx);
-                num_cmpl++;
+                tx_compl++;
         }
 
-        if (num_cmpl) {
-                be_cq_notify(adapter, tx_cq->id, true, num_cmpl);
+        mcc_compl = be_process_mcc(adapter, &status);
+
+        napi_complete(napi);
+
+        if (mcc_compl) {
+                struct be_mcc_obj *mcc_obj = &adapter->mcc_obj;
+                be_cq_notify(adapter, mcc_obj->cq.id, true, mcc_compl);
+        }
+
+        if (tx_compl) {
+                be_cq_notify(adapter, adapter->tx_obj.cq.id, true, tx_compl);
 
                 /* As Tx wrbs have been freed up, wake up netdev queue if
                  * it was stopped due to lack of tx wrbs.
@@ -1496,24 +1511,8 @@ void be_process_tx(struct be_adapter *adapter)
                 }
 
                 drvr_stats(adapter)->be_tx_events++;
-                drvr_stats(adapter)->be_tx_compl += num_cmpl;
+                drvr_stats(adapter)->be_tx_compl += tx_compl;
         }
-}
-
-/* As TX and MCC share the same EQ check for both TX and MCC completions.
- * For TX/MCC we don't honour budget; consume everything
- */
-static int be_poll_tx_mcc(struct napi_struct *napi, int budget)
-{
-        struct be_eq_obj *tx_eq = container_of(napi, struct be_eq_obj, napi);
-        struct be_adapter *adapter =
-                container_of(tx_eq, struct be_adapter, tx_eq);
-
-        napi_complete(napi);
-
-        be_process_tx(adapter);
-
-        be_process_mcc(adapter);
 
         return 1;
 }