From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net-next 1/2] net: prepare (struct ubuf_info)->refcnt conversion Date: Thu, 31 Aug 2017 13:30:12 -0700 Message-ID: <20170831203013.9219-2-edumazet@google.com> References: <20170831203013.9219-1-edumazet@google.com> Cc: netdev , Willem de Bruijn , Eric Dumazet , Eric Dumazet To: "David S . Miller" Return-path: Received: from mail-pf0-f169.google.com ([209.85.192.169]:33430 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751053AbdHaUaW (ORCPT ); Thu, 31 Aug 2017 16:30:22 -0400 Received: by mail-pf0-f169.google.com with SMTP id n73so2123185pfj.0 for ; Thu, 31 Aug 2017 13:30:22 -0700 (PDT) In-Reply-To: <20170831203013.9219-1-edumazet@google.com> Sender: netdev-owner@vger.kernel.org List-ID: In order to convert this atomic_t refcnt to refcount_t, we need to init the refcount to one to not trigger a 0 -> 1 transition. This also removes one atomic operation in fast path. Signed-off-by: Eric Dumazet --- net/core/skbuff.c | 3 ++- net/ipv4/tcp.c | 2 -- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 917da73d3ab3b82163cf0a9ee944da09cb5a391f..65b9ca3945f8fd2b1bef4aef5dd774be04e5d128 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -963,7 +963,7 @@ struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size) uarg->len = 1; uarg->bytelen = size; uarg->zerocopy = 1; - atomic_set(&uarg->refcnt, 0); + atomic_set(&uarg->refcnt, 1); sock_hold(sk); return uarg; @@ -1005,6 +1005,7 @@ struct ubuf_info *sock_zerocopy_realloc(struct sock *sk, size_t size, uarg->len++; uarg->bytelen = bytelen; atomic_set(&sk->sk_zckey, ++next); + sock_zerocopy_get(uarg); return uarg; } } diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 21ca2df274c5130a13d31a391a1408d779af34af..fff4d7bc3b8b46174e7bd0a04d7c212307e55cb5 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1190,8 +1190,6 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) goto out_err; } - /* skb may be freed in main loop, keep extra ref on uarg */ - sock_zerocopy_get(uarg); if (!(sk_check_csum_caps(sk) && sk->sk_route_caps & NETIF_F_SG)) uarg->zerocopy = 0; } -- 2.14.1.581.gf28d330327-goog