Xen devel - Oct 2007 - [PATCH 6/6] Network acceleration improvements

Signed-off-by: Kieran Mansley <kmansley@solarflare.com> 

Cleanup vif_state on device removal

diff -r f992a517aba5 drivers/xen/netfront/accel.c
--- a/drivers/xen/netfront/accel.c	Wed Oct 03 13:41:33 2007 +0100
+++ b/drivers/xen/netfront/accel.c	Wed Oct 03 13:45:55 2007 +0100
@@ -500,6 +500,30 @@ EXPORT_SYMBOL_GPL(netfront_accelerator_r
 
 
 /* 
+ * Remove the hooks from a single vif state.
+ */
+static void 
+accelerator_remove_single_hook(struct netfront_accelerator *accelerator,
+			       struct netfront_accel_vif_state *vif_state)
+{
+	/* Make sure there are no data path operations going on */
+	netif_poll_disable(vif_state->np->netdev);
+	netif_tx_lock_bh(vif_state->np->netdev);
+
+	/* 
+	 * Remove the hooks, but leave the vif_state on the
+	 * accelerator''s list as that signifies this vif is
+	 * interested in using that accelerator if it becomes
+	 * available again
+	 */
+	vif_state->hooks = NULL;
+	
+	netif_tx_unlock_bh(vif_state->np->netdev);
+	netif_poll_enable(vif_state->np->netdev);		       
+}
+
+
+/* 
  * Safely remove the accelerator function hooks from a netfront state.
  */
 static void accelerator_remove_hooks(struct netfront_accelerator *accelerator,
@@ -513,20 +537,7 @@ static void accelerator_remove_hooks(str
 	list_for_each_entry_safe(vif_state, tmp,
 				 &accelerator->vif_states,
 				 link) {
-		/* Make sure there are no data path operations going on */
-		netif_poll_disable(vif_state->np->netdev);
-		netif_tx_lock_bh(vif_state->np->netdev);
-
-		/* 
-		 * Remove the hooks, but leave the vif_state on the
-		 * accelerator''s list as that signifies this vif is
-		 * interested in using that accelerator if it becomes
-		 * available again
-		 */
-		vif_state->hooks = NULL;
-		
-		netif_tx_unlock_bh(vif_state->np->netdev);
-		netif_poll_enable(vif_state->np->netdev);
+		accelerator_remove_single_hook(accelerator, vif_state);
 
 		/* 
 		 * Remove the reference taken when the vif_state hooks
@@ -623,6 +634,8 @@ int netfront_accelerator_call_remove(str
 int netfront_accelerator_call_remove(struct netfront_info *np,
 				     struct xenbus_device *dev)
 {
+	struct netfront_accelerator *accelerator = np->accelerator;
+	struct netfront_accel_vif_state *tmp_vif_state;
 	struct netfront_accel_hooks *hooks;
 	unsigned flags;
 	int rc = 0;
@@ -633,23 +646,53 @@ int netfront_accelerator_call_remove(str
 	 * call to prevent the accelerator being able to modify the
 	 * hooks in the middle (by, for example, unloading)
 	 */ 
-	if (np->accel_vif_state.hooks) {
-		spin_lock_irqsave(&np->accelerator->vif_states_lock, flags); 
-		hooks = np->accel_vif_state.hooks;
-		if (hooks) {
-			kref_get(&np->accel_vif_state.vif_kref);
-			spin_unlock_irqrestore
-				(&np->accelerator->vif_states_lock, flags);
-
-			rc = np->accel_vif_state.hooks->remove(dev);
-
-			kref_put(&np->accel_vif_state.vif_kref,
-				 vif_kref_release);
-		} else {
-			spin_unlock_irqrestore
-				(&np->accelerator->vif_states_lock, flags);
-		}
-	}
+	spin_lock_irqsave(&np->accelerator->vif_states_lock, flags); 
+	hooks = np->accel_vif_state.hooks;
+
+	/*
+	 * Remove this vif_state from the accelerator''s list 
+	 */
+	list_for_each_entry(tmp_vif_state, &accelerator->vif_states, link) {
+		if (tmp_vif_state == &np->accel_vif_state) {
+			list_del(&np->accel_vif_state.link);
+			break;
+		}
+	}
+	   
+	if (hooks) {
+		kref_get(&np->accel_vif_state.vif_kref);
+		spin_unlock_irqrestore
+			(&np->accelerator->vif_states_lock, flags);
+		
+		rc = np->accel_vif_state.hooks->remove(dev);
+		
+		kref_put(&np->accel_vif_state.vif_kref,
+			 vif_kref_release);
+		
+		spin_lock_irqsave(&np->accelerator->vif_states_lock,
+				  flags);
+
+		/* 
+		 * Try and do the opposite of accelerator_probe_new_vif
+		 * to ensure there''s no state pointing back at the 
+		 * netdev 
+		 */
+		accelerator_remove_single_hook(accelerator, 
+					       &np->accel_vif_state);
+				
+		/* 
+		 * Remove the reference taken when the vif_state hooks
+		 * were set, must be called without lock held
+		 */
+		spin_unlock_irqrestore(&accelerator->vif_states_lock,
+				       flags);
+		kref_put(&np->accel_vif_state.vif_kref,
+			 vif_kref_release);
+	} else {
+		spin_unlock_irqrestore(&np->accelerator->vif_states_lock,
+				       flags); 
+	}
+
 	return rc;
 }
 



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