From db5bce32fbe19f0c7482fb5a40a33178bbe7b11b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 31 Aug 2017 16:48:21 -0700 Subject: [PATCH] net: prepare (struct ubuf_info)->refcnt conversion 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. v2: removed dead code in sock_zerocopy_put_abort() as suggested by Willem. Signed-off-by: Eric Dumazet Acked-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/core/skbuff.c | 10 ++-------- net/ipv4/tcp.c | 2 -- 2 files changed, 2 insertions(+), 10 deletions(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 246ca1c81715..a003f953a0a6 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; } } @@ -1102,13 +1103,6 @@ void sock_zerocopy_put_abort(struct ubuf_info *uarg) atomic_dec(&sk->sk_zckey); uarg->len--; - /* sock_zerocopy_put expects a ref. Most sockets take one per - * skb, which is zero on abort. tcp_sendmsg holds one extra, to - * avoid an skb send inside the main loop triggering uarg free. - */ - if (sk->sk_type != SOCK_STREAM) - atomic_inc(&uarg->refcnt); - sock_zerocopy_put(uarg); } } diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 7a3d84375836..5091402720ab 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; } -- 2.20.1