cnic: Don't take rcu_read_lock in cnic_rcv_netevent()

Because the called function, such as bnx2fc_indicate_netevent(), can sleep,
we cannot take rcu_lock().  To prevent the rcu protected ulp_ops from going
away, we use the cnic_lock mutex and set the ULP_F_CALL_PENDING flag.
The code already waits for ULP_F_CALL_PENDING flag to clear in
cnic_unregister_device().

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/net/ethernet/broadcom/cnic.c b/drivers/net/ethernet/broadcom/cnic.c
index 09f3fefcbf9c..a0aae722ffcf 100644
--- a/drivers/net/ethernet/broadcom/cnic.c
+++ b/drivers/net/ethernet/broadcom/cnic.c
@@ -5624,20 +5624,27 @@ static void cnic_rcv_netevent(struct cnic_local *cp, unsigned long event,
 {
         int if_type;
 
-        rcu_read_lock();
         for (if_type = 0; if_type < MAX_CNIC_ULP_TYPE; if_type++) {
                 struct cnic_ulp_ops *ulp_ops;
                 void *ctx;
 
-                ulp_ops = rcu_dereference(cp->ulp_ops[if_type]);
-                if (!ulp_ops || !ulp_ops->indicate_netevent)
+                mutex_lock(&cnic_lock);
+                ulp_ops = rcu_dereference_protected(cp->ulp_ops[if_type],
+                                                lockdep_is_held(&cnic_lock));
+                if (!ulp_ops || !ulp_ops->indicate_netevent) {
+                        mutex_unlock(&cnic_lock);
                         continue;
+                }
 
                 ctx = cp->ulp_handle[if_type];
 
+                set_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);
+                mutex_unlock(&cnic_lock);
+
                 ulp_ops->indicate_netevent(ctx, event, vlan_id);
+
+                clear_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);
         }
-        rcu_read_unlock();
 }
 
 /* netdev event handler */