netvsc: add comments about callback's and NAPI

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

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger 2017-03-16 16:12:38 -07:00 committed by David S. Miller
parent 6de38af611
commit 262b7f142a
1 changed files with 12 additions and 1 deletions

View File

@ -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;