4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matthew Cover <werekraken@xxxxxxxxx>
[ Upstream commit 8ebebcba559a1bfbaec7bbda64feb9870b9c58da ]
When writing packets to a descriptor associated with a combined queue, the
packets should end up on that queue.
Before this change all packets written to any descriptor associated with a
tap interface end up on rx-0, even when the descriptor is associated with a
different queue.
The rx traffic can be generated by either of the following.
1. a simple tap program which spins up multiple queues and writes packets
to each of the file descriptors
2. tx from a qemu vm with a tap multiqueue netdev
The queue for rx traffic can be observed by either of the following (done
on the hypervisor in the qemu case).
1. a simple netmap program which opens and reads from per-queue
descriptors
2. configuring RPS and doing per-cpu captures with rxtxcpu
Alternatively, if you printk() the return value of skb_get_rx_queue() just
before each instance of netif_receive_skb() in tun.c, you will get 65535
for every skb.
Calling skb_record_rx_queue() to set the rx queue to the queue_index fixes
the association between descriptor and rx queue.
Signed-off-by: Matthew Cover <matthew.cover@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/tun.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1527,6 +1527,7 @@ static void tun_rx_batched(struct tun_st
if (!rx_batched || (!more && skb_queue_empty(queue))) {
local_bh_disable();
+ skb_record_rx_queue(skb, tfile->queue_index);
netif_receive_skb(skb);
local_bh_enable();
return;
@@ -1546,8 +1547,11 @@ static void tun_rx_batched(struct tun_st
struct sk_buff *nskb;
local_bh_disable();
- while ((nskb = __skb_dequeue(&process_queue)))
+ while ((nskb = __skb_dequeue(&process_queue))) {
+ skb_record_rx_queue(nskb, tfile->queue_index);
netif_receive_skb(nskb);
+ }
+ skb_record_rx_queue(skb, tfile->queue_index);
netif_receive_skb(skb);
local_bh_enable();
}
