diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-06-06 07:41:15 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-06-07 10:08:45 +0100 |
| commit | 5c3b74a92aa285a3df722bf6329ba7ccf70346d6 (patch) | |
| tree | a5898632fd2ce3dd1f7dfca691a0a1f6dfdf1231 /net | |
| parent | 1e5c647c3f6d4f8497dedcd226204e1880e0ffb3 (diff) | |
rfs: annotate lockless accesses to RFS sock flow table
Add READ_ONCE()/WRITE_ONCE() on accesses to the sock flow table.
This also prevents a (smart ?) compiler to remove the condition in:
if (table->ents[index] != newval)
table->ents[index] = newval;
We need the condition to avoid dirtying a shared cache line.
Fixes: fec5e652e58f ("rfs: Receive Flow Steering")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index b3c13e041935..1495f8aff288 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4471,8 +4471,10 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, u32 next_cpu; u32 ident; - /* First check into global flow table if there is a match */ - ident = sock_flow_table->ents[hash & sock_flow_table->mask]; + /* First check into global flow table if there is a match. + * This READ_ONCE() pairs with WRITE_ONCE() from rps_record_sock_flow(). + */ + ident = READ_ONCE(sock_flow_table->ents[hash & sock_flow_table->mask]); if ((ident ^ hash) & ~rps_cpu_mask) goto try_rps; |