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Commit db5bce32 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 487234cc

net/core/skbuff.c

+2 −8
Original line number Diff line number Diff line
@@ -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);

	}

}

net/ipv4/tcp.c

+0 −2
Original line number Diff line number Diff line
@@ -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;

	}