Drivers: hv: vmbus: Implement per-CPU mapping of relid to channel

[firefly-linux-kernel-4.4.55.git] / drivers / hv / connection.c

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index df2363ea017f0383934348187f2e005c36e28fb9..7f10c151632acc5730e7840fb482909f090bae6f 100644 (file)
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -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
@@ -285,7 +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);