From: "Toke Høiland-Jørgensen" <toke@redhat•com>
To: Martin KaFai Lau <kafai@fb•com>
Cc: bpf@vger•kernel.org, netdev@vger•kernel.org,
Hangbin Liu <liuhangbin@gmail•com>,
Jesper Dangaard Brouer <brouer@redhat•com>,
Magnus Karlsson <magnus.karlsson@gmail•com>,
"Paul E . McKenney" <paulmck@kernel•org>
Subject: Re: [PATCH bpf-next 04/17] xdp: add proper __rcu annotations to redirect map entries
Date: Fri, 11 Jun 2021 01:41:17 +0200 [thread overview]
Message-ID: <875yyluw2q.fsf@toke.dk> (raw)
In-Reply-To: <20210610233250.pef2dwo2r5atluwt@kafai-mbp>
Martin KaFai Lau <kafai@fb•com> writes:
> On Fri, Jun 11, 2021 at 01:19:04AM +0200, Toke Høiland-Jørgensen wrote:
>> >> @@ -149,7 +152,8 @@ static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
>> >> u64 map_flags)
>> >> {
>> >> struct xsk_map *m = container_of(map, struct xsk_map, map);
>> >> - struct xdp_sock *xs, *old_xs, **map_entry;
>> >> + struct xdp_sock __rcu **map_entry;
>> >> + struct xdp_sock *xs, *old_xs;
>> >> u32 i = *(u32 *)key, fd = *(u32 *)value;
>> >> struct xsk_map_node *node;
>> >> struct socket *sock;
>> >> @@ -179,7 +183,7 @@ static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
>> >> }
>> >>
>> >> spin_lock_bh(&m->lock);
>> >> - old_xs = READ_ONCE(*map_entry);
>> >> + old_xs = rcu_dereference_check(*map_entry, rcu_read_lock_bh_held());
>> > Is it actually protected by the m->lock at this point?
>>
>> True, can just add that to the check.
> this should be enough
> rcu_dereference_protected(*map_entry, lockdep_is_held(&m->lock));
Right, that's what I had in mind as well :)
-Toke
next prev parent reply other threads:[~2021-06-10 23:41 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 10:33 [PATCH bpf-next 00/17] Clean up and document RCU-based object protection for XDP_REDIRECT Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 01/17] rcu: Create an unrcu_pointer() to remove __rcu from a pointer Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 02/17] bpf: allow RCU-protected lookups to happen from bh context Toke Høiland-Jørgensen
2021-06-10 18:38 ` Alexei Starovoitov
2021-06-10 21:24 ` Daniel Borkmann
2021-06-10 22:27 ` Toke Høiland-Jørgensen
2021-06-10 19:33 ` Martin KaFai Lau
2021-06-09 10:33 ` [PATCH bpf-next 03/17] dev: add rcu_read_lock_bh_held() as a valid check when getting a RCU dev ref Toke Høiland-Jørgensen
2021-06-10 19:37 ` Martin KaFai Lau
2021-06-10 23:05 ` Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 04/17] xdp: add proper __rcu annotations to redirect map entries Toke Høiland-Jørgensen
2021-06-10 21:09 ` Martin KaFai Lau
2021-06-10 23:19 ` Toke Høiland-Jørgensen
2021-06-10 23:32 ` Martin KaFai Lau
2021-06-10 23:41 ` Toke Høiland-Jørgensen [this message]
2021-06-09 10:33 ` [PATCH bpf-next 05/17] ena: remove rcu_read_lock() around XDP program invocation Toke Høiland-Jørgensen
2021-06-09 13:57 ` Paul E. McKenney
2021-06-09 10:33 ` [PATCH bpf-next 06/17] bnxt: " Toke Høiland-Jørgensen
2021-06-09 13:58 ` Paul E. McKenney
2021-06-10 8:47 ` Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 07/17] thunderx: " Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 08/17] freescale: " Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 09/17] net: intel: " Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 10/17] marvell: " Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 11/17] mlx4: " Toke Høiland-Jørgensen
2021-06-10 7:10 ` Tariq Toukan
2021-06-09 10:33 ` [PATCH bpf-next 12/17] nfp: " Toke Høiland-Jørgensen
2021-06-11 16:30 ` Simon Horman
2021-06-09 10:33 ` [PATCH bpf-next 13/17] qede: " Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 14/17] sfc: " Toke Høiland-Jørgensen
2021-06-09 12:15 ` Edward Cree
2021-06-09 10:33 ` [PATCH bpf-next 15/17] netsec: " Toke Høiland-Jørgensen
2021-06-10 5:30 ` Ilias Apalodimas
2021-06-09 10:33 ` [PATCH bpf-next 16/17] stmmac: " Toke Høiland-Jørgensen
2021-06-09 10:33 ` [PATCH bpf-next 17/17] net: ti: " Toke Høiland-Jørgensen
2021-06-09 17:04 ` Grygorii Strashko
2021-06-10 0:18 ` [PATCH bpf-next 00/17] Clean up and document RCU-based object protection for XDP_REDIRECT Yonghong Song
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