There is a race between napi_reschedule and re-enabling interrupts
which could lead to missed host interrrupts. This occurs when
interrupts are re-enabled (hv_end_read) and vmbus irq callback
(netvsc_channel_cb) has already scheduled NAPI.
Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
---
drivers/net/hyperv/netvsc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index ff97a85b2e9d..4237cedc4f08 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -1207,9 +1207,10 @@ int netvsc_poll(struct napi_struct *napi, int budget)
if (send_recv_completions(ndev, net_device, nvchan) == 0 &&
work_done < budget &&
napi_complete_done(napi, work_done) &&
- hv_end_read(&channel->inbound)) {
+ hv_end_read(&channel->inbound) &&
+ napi_schedule_prep(napi)) {
hv_begin_read(&channel->inbound);
- napi_reschedule(napi);
+ __napi_schedule(napi);
}
/* Driver may overshoot since multiple packets per descriptor */
--
2.16.1
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