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xsk: simplify AF_XDP socket teardown

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Prior this commit, when the struct socket object was being released,
the UMEM did not have its reference count decreased. Instead, this was
done in the struct sock sk_destruct function.

There is no reason to keep the UMEM reference around when the socket
is being orphaned, so in this patch the xdp_put_mem is called in the
xsk_release function. This results in that the xsk_destruct function
can be removed!

Note that, it still holds that a struct xsk_sock reference might still
linger in the XSKMAP after the UMEM is released, e.g. if a user does
not clear the XSKMAP prior to closing the process. This sock will be
in a "released" zombie like state, until the XSKMAP is removed.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Björn Töpel 2018-12-19 13:09:31 +01:00 committed by Daniel Borkmann
parent 76c43ae84e
commit e2ce367488
1 changed files with 1 additions and 15 deletions
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16
net/xdp/xsk.c
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@ -366,6 +366,7 @@ static int xsk_release(struct socket *sock)
xskq_destroy(xs->rx);
xskq_destroy(xs->tx);
xdp_put_umem(xs->umem);
sock_orphan(sk);
sock->sk = NULL;
@ -713,18 +714,6 @@ static const struct proto_ops xsk_proto_ops = {
.sendpage = sock_no_sendpage,
};
static void xsk_destruct(struct sock *sk)
{
struct xdp_sock *xs = xdp_sk(sk);
if (!sock_flag(sk, SOCK_DEAD))
return;
xdp_put_umem(xs->umem);
sk_refcnt_debug_dec(sk);
}
static int xsk_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
@ -751,9 +740,6 @@ static int xsk_create(struct net *net, struct socket *sock, int protocol,
sk->sk_family = PF_XDP;
sk->sk_destruct = xsk_destruct;
sk_refcnt_debug_inc(sk);
sock_set_flag(sk, SOCK_RCU_FREE);
xs = xdp_sk(sk);