1 files changed, 29 insertions, 10 deletions

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 2e7801af466..e84f4526eb3 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -224,8 +224,8 @@ cleanup:
 		vmbus_connection.int_page = NULL;
 	}
 
-	free_pages((unsigned long)vmbus_connection.monitor_pages[0], 1);
-	free_pages((unsigned long)vmbus_connection.monitor_pages[1], 1);
+	free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
+	free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
 	vmbus_connection.monitor_pages[0] = NULL;
 	vmbus_connection.monitor_pages[1] = NULL;
 
@@ -234,6 +234,28 @@ cleanup:
 	return ret;
 }
 
+/*
+ * Map the given relid to the corresponding channel based on the
+ * per-cpu list of channels that have been affinitized to this CPU.
+ * This will be used in the channel callback path as we can do this
+ * mapping in a lock-free fashion.
+ */
+static struct vmbus_channel *pcpu_relid2channel(u32 relid)
+{
+	struct vmbus_channel *channel;
+	struct vmbus_channel *found_channel  = NULL;
+	int cpu = smp_processor_id();
+	struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
+
+	list_for_each_entry(channel, pcpu_head, percpu_list) {
+		if (channel->offermsg.child_relid == relid) {
+			found_channel = channel;
+			break;
+		}
+	}
+
+	return found_channel;
+}
 
 /*
  * relid2channel - Get the channel object given its
@@ -277,7 +299,6 @@ struct vmbus_channel *relid2channel(u32 relid)
 static void process_chn_event(u32 relid)
 {
 	struct vmbus_channel *channel;
-	unsigned long flags;
 	void *arg;
 	bool read_state;
 	u32 bytes_to_read;
@@ -286,7 +307,7 @@ static void process_chn_event(u32 relid)
 	 * Find the channel based on this relid and invokes the
 	 * channel callback to process the event
 	 */
-	channel = relid2channel(relid);
+	channel = pcpu_relid2channel(relid);
 
 	if (!channel) {
 		pr_err("channel not found for relid - %u\n", relid);
@@ -296,13 +317,12 @@ static void process_chn_event(u32 relid)
 	/*
 	 * A channel once created is persistent even when there
 	 * is no driver handling the device. An unloading driver
-	 * sets the onchannel_callback to NULL under the
-	 * protection of the channel inbound_lock. Thus, checking
-	 * and invoking the driver specific callback takes care of
-	 * orderly unloading of the driver.
+	 * sets the onchannel_callback to NULL on the same CPU
+	 * as where this interrupt is handled (in an interrupt context).
+	 * Thus, checking and invoking the driver specific callback takes
+	 * care of orderly unloading of the driver.
 	 */
 
-	spin_lock_irqsave(&channel->inbound_lock, flags);
 	if (channel->onchannel_callback != NULL) {
 		arg = channel->channel_callback_context;
 		read_state = channel->batched_reading;
@@ -327,7 +347,6 @@ static void process_chn_event(u32 relid)
 		pr_err("no channel callback for relid - %u\n", relid);
 	}
 
-	spin_unlock_irqrestore(&channel->inbound_lock, flags);
 }
 
 /*