hv_netvsc: Fix napi reschedule while receive completion is busy

If out ring is full temporarily and receive completion cannot go out, we may still need to reschedule napi if certain conditions are met. Otherwise the napi poll might be stopped forever, and cause network disconnect. Fixes: 7426b1a ("netvsc: optimize receive completions") Signed-off-by: Stephen Hemminger <[email protected]> Signed-off-by: Haiyang Zhang <[email protected]> Signed-off-by: David S. Miller <[email protected]>
ambv · Jul 18, 2018 · 6b81b19 · 6b81b19
1 parent a2ec9d1
commit 6b81b19
Showing 1 changed file with 10 additions and 7 deletions.
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
@@ -1274,6 +1274,7 @@ int netvsc_poll(struct napi_struct *napi, int budget)
 	struct hv_device *device = netvsc_channel_to_device(channel);
 	struct net_device *ndev = hv_get_drvdata(device);
 	int work_done = 0;
+	int ret;
 
 	/* If starting a new interval */
 	if (!nvchan->desc)
@@ -1285,16 +1286,18 @@ int netvsc_poll(struct napi_struct *napi, int budget)
 		nvchan->desc = hv_pkt_iter_next(channel, nvchan->desc);
 	}
 
-	/* If send of pending receive completions suceeded
-	 *   and did not exhaust NAPI budget this time
-	 *   and not doing busy poll
+	/* Send any pending receive completions */
+	ret = send_recv_completions(ndev, net_device, nvchan);
+
+	/* If it did not exhaust NAPI budget this time
+	 *  and not doing busy poll
 	 * then re-enable host interrupts
-	 *     and reschedule if ring is not empty.
+	 *  and reschedule if ring is not empty
+	 *   or sending receive completion failed.
 	 */
-	if (send_recv_completions(ndev, net_device, nvchan) == 0 &&
-	    work_done < budget &&
+	if (work_done < budget &&
 	    napi_complete_done(napi, work_done) &&
-	    hv_end_read(&channel->inbound) &&
+	    (ret || hv_end_read(&channel->inbound)) &&
 	    napi_schedule_prep(napi)) {
 		hv_begin_read(&channel->inbound);
 		__napi_schedule(napi);