From 262b7f142a50badde4032e925902a0d0ad89eb7f Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Thu, 16 Mar 2017 16:12:38 -0700 Subject: [PATCH] netvsc: add comments about callback's and NAPI Add some short description of how callback's and NAPI interoperate. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- 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; -- 2.20.1