[PATCH net-next 2/3] netvsc: add comments about callback's and NAPI

[Stephen Hemminger]

Add some short description of how callback's and NAPI interoperate.

Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
---
 drivers/net/hyperv/netvsc.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 0a2e9bd98d2c..989b7cd99380 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -1209,6 +1209,10 @@ static struct hv_device *netvsc_channel_to_device(struct 
vmbus_channel *channel)
        return primary ? primary->device_obj : channel->device_obj;
 }
 
+/* Network processing softirq
+ * Process data in incoming ring buffer from host
+ * Stops when ring is empty or budget is met or exceeded.
+ */
 int netvsc_poll(struct napi_struct *napi, int budget)
 {
        struct netvsc_channel *nvchan
@@ -1238,7 +1242,11 @@ int netvsc_poll(struct napi_struct *napi, int budget)
        }
        hv_pkt_iter_close(channel);
 
-       /* If ring is empty and NAPI is not doing polling */
+       /* If budget was not exhausted and
+        * not doing busy poll
+        * then re-enable host interrupts
+        *  and reschedule if ring is not empty.
+        */
        if (work_done < budget &&
            napi_complete_done(napi, work_done) &&
            hv_end_read(&channel->inbound) != 0)
@@ -1248,6 +1256,9 @@ int netvsc_poll(struct napi_struct *napi, int budget)
        return work_done;
 }
 
+/* Call back when data is available in host ring buffer.
+ * Processing is deferred until network softirq (NAPI)
+ */
 void netvsc_channel_cb(void *context)
 {
        struct netvsc_channel *nvchan = context;
-- 
2.11.0