Commit 4d54cc32 authored by Florian Westphal's avatar Florian Westphal Committed by David S. Miller
Browse files

mptcp: avoid lock_fast usage in accept path 



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: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6c714f1b

include/net/genetlink.h

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
 */

struct genl_multicast_group {

	char			name[GENL_NAMSIZ];

	u8			flags;

};



struct genl_ops;

net/mptcp/protocol.c

+2 −3
Original line number Diff line number Diff line
@@ -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))

net/netlink/genetlink.c

+32 −0
Original line number Diff line number Diff line
@@ -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 */