[PATCH v2 net-next 2/3] gro: consistentify napi->gro_hash[x] access in dev_gro_receive()

From: Alexander Lobakin
Date: Sat Mar 13 2021 - 15:31:52 EST


GRO bucket index doesn't change through the entire function.
Store a pointer to the corresponding bucket instead of its member
and use it consistently through the function.
It is performance-safe since &gro_list->list == gro_list.

Misc: remove superfluous braces around single-line branches.

Signed-off-by: Alexander Lobakin <alobakin@xxxxx>
---
net/core/dev.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 1317e6b6758a..b635467087f3 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5953,7 +5953,7 @@ static void gro_flush_oldest(struct napi_struct *napi, struct list_head *head)
static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
{
u32 hash = skb_get_hash_raw(skb) & (GRO_HASH_BUCKETS - 1);
- struct list_head *gro_head = &napi->gro_hash[hash].list;
+ struct gro_list *gro_list = &napi->gro_hash[hash];
struct list_head *head = &offload_base;
struct packet_offload *ptype;
__be16 type = skb->protocol;
@@ -5965,7 +5965,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
if (netif_elide_gro(skb->dev))
goto normal;

- gro_list_prepare(gro_head, skb);
+ gro_list_prepare(&gro_list->list, skb);

rcu_read_lock();
list_for_each_entry_rcu(ptype, head, list) {
@@ -6001,7 +6001,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff

pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
ipv6_gro_receive, inet_gro_receive,
- gro_head, skb);
+ &gro_list->list, skb);
break;
}
rcu_read_unlock();
@@ -6020,7 +6020,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
if (pp) {
skb_list_del_init(pp);
napi_gro_complete(napi, pp);
- napi->gro_hash[hash].count--;
+ gro_list->count--;
}

if (same_flow)
@@ -6029,16 +6029,16 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
if (NAPI_GRO_CB(skb)->flush)
goto normal;

- if (unlikely(napi->gro_hash[hash].count >= MAX_GRO_SKBS)) {
- gro_flush_oldest(napi, gro_head);
- } else {
- napi->gro_hash[hash].count++;
- }
+ if (unlikely(gro_list->count >= MAX_GRO_SKBS))
+ gro_flush_oldest(napi, &gro_list->list);
+ else
+ gro_list->count++;
+
NAPI_GRO_CB(skb)->count = 1;
NAPI_GRO_CB(skb)->age = jiffies;
NAPI_GRO_CB(skb)->last = skb;
skb_shinfo(skb)->gso_size = skb_gro_len(skb);
- list_add(&skb->list, gro_head);
+ list_add(&skb->list, &gro_list->list);
ret = GRO_HELD;

pull:
@@ -6046,7 +6046,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
if (grow > 0)
gro_pull_from_frag0(skb, grow);
ok:
- if (napi->gro_hash[hash].count) {
+ if (gro_list->count) {
if (!test_bit(hash, &napi->gro_bitmask))
__set_bit(hash, &napi->gro_bitmask);
} else if (test_bit(hash, &napi->gro_bitmask)) {
--
2.30.2