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mptcp: avoid lock_fast usage in accept path

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Once event support is added this may need to allocate memory while msk
lock is held with softirqs disabled.

Not using lock_fast also allows to do the allocation with GFP_KERNEL.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Westphal 2021-02-12 15:59:59 -08:00 • committed by David S. Miller
parent 6c714f1b54
commit 4d54cc3211
3 changed files with 35 additions and 3 deletions
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1
include/net/genetlink.h
View file

@ -14,6 +14,7 @@
*/
struct genl_multicast_group {
char name[GENL_NAMSIZ];
u8 flags;
};
struct genl_ops;

5
net/mptcp/protocol.c
View file

@ -3260,9 +3260,8 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
struct mptcp_sock *msk = mptcp_sk(newsock->sk);
struct mptcp_subflow_context *subflow;
struct sock *newsk = newsock->sk;
bool slowpath;
slowpath = lock_sock_fast(newsk);
lock_sock(newsk);
/* PM/worker can now acquire the first subflow socket
* lock without racing with listener queue cleanup,
@ -3288,7 +3287,7 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
if (!ssk->sk_socket)
mptcp_sock_graft(ssk, newsock);
}
unlock_sock_fast(newsk, slowpath);
release_sock(newsk);
}
if (inet_csk_listen_poll(ssock->sk))

32
net/netlink/genetlink.c
View file

@ -1360,11 +1360,43 @@ static struct genl_family genl_ctrl __ro_after_init = {
.netnsok = true,
};
static int genl_bind(struct net *net, int group)
{
const struct genl_family *family;
unsigned int id;
int ret = 0;
genl_lock_all();
idr_for_each_entry(&genl_fam_idr, family, id) {
const struct genl_multicast_group *grp;
int i;
if (family->n_mcgrps == 0)
continue;
i = group - family->mcgrp_offset;
if (i < 0 || i >= family->n_mcgrps)
continue;
grp = &family->mcgrps[i];
if ((grp->flags & GENL_UNS_ADMIN_PERM) &&
!ns_capable(net->user_ns, CAP_NET_ADMIN))
ret = -EPERM;
break;
}
genl_unlock_all();
return ret;
}
static int __net_init genl_pernet_init(struct net *net)
{
struct netlink_kernel_cfg cfg = {
.input = genl_rcv,
.flags = NL_CFG_F_NONROOT_RECV,
.bind = genl_bind,
};
/* we'll bump the group number right afterwards */