Re: [PATCH net-next 6/6] net: hns3: use napi_consume_skb() when cleaning tx desc

On 2020/9/15 13:09, Saeed Mahameed wrote:

On Mon, 2020-09-14 at 20:06 +0800, Huazhong Tan wrote:

quoted

From: Yunsheng Lin <redacted>

Use napi_consume_skb() to batch consuming skb when cleaning
tx desc in NAPI polling.

Signed-off-by: Yunsheng Lin <redacted>
Signed-off-by: Huazhong Tan <redacted>
---
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c    | 27 +++++++++++-
----------
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.h    |  2 +-
 drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c |  4 ++--
 3 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 4a49a76..feeaf75 100644

--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

@@ -2333,10 +2333,10 @@ static int hns3_alloc_buffer(struct

hns3_enet_ring *ring,
 }
 
 static void hns3_free_buffer(struct hns3_enet_ring *ring,
-			     struct hns3_desc_cb *cb)
+			     struct hns3_desc_cb *cb, int budget)
 {
 	if (cb->type == DESC_TYPE_SKB)
-		dev_kfree_skb_any((struct sk_buff *)cb->priv);
+		napi_consume_skb(cb->priv, budget);

This code can be reached from hns3_lb_clear_tx_ring() below which is
your loopback test and called with non-zero budget, I am not sure you
are allowed to call napi_consume_skb() with non-zero budget outside
napi context, perhaps the cb->type for loopback test is different in lb
test case ? Idk.. , please double check other code paths.

Yes, loopback test may call napi_consume_skb() with non-zero budget outside
napi context. Thanks for pointing out this case.

How about add the below WARN_ONCE() in napi_consume_skb() to catch this
kind of error?

WARN_ONCE(!in_serving_softirq(), "napi_consume_skb() is called with non-zero budget outside napi context");

[...]

quoted

 static void hns3_lb_clear_tx_ring(struct hns3_nic_priv *priv, u32
start_ringid,
-				  u32 end_ringid, u32 budget)
+				  u32 end_ringid, int budget)
 {
 	u32 i;
 
 	for (i = start_ringid; i <= end_ringid; i++) {
 		struct hns3_enet_ring *ring = &priv->ring[i];
 
-		hns3_clean_tx_ring(ring);
+		hns3_clean_tx_ring(ring, budget);
 	}
 }