From: John Fastabend <john.fastabend@gmail.com>
To: Martin Lau <kafai@fb.com>, Jakub Sitnicki <jakub@cloudflare.com>
Cc: "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"kernel-team@cloudflare.com" <kernel-team@cloudflare.com>,
Eric Dumazet <edumazet@google.com>,
John Fastabend <john.fastabend@gmail.com>,
Lorenz Bauer <lmb@cloudflare.com>
Subject: Re: [PATCH bpf-next v2 07/11] bpf, sockmap: Return socket cookie on lookup from syscall
Date: Mon, 13 Jan 2020 19:16:29 -0800 [thread overview]
Message-ID: <5e1d328d760e_78752af1940225b4b7@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <20200113231223.cl77bxxs44bl6uhw@kafai-mbp.dhcp.thefacebook.com>
Martin Lau wrote:
> On Fri, Jan 10, 2020 at 11:50:23AM +0100, Jakub Sitnicki wrote:
> > Tooling that populates the SOCKMAP with sockets from user-space needs a way
> > to inspect its contents. Returning the struct sock * that SOCKMAP holds to
> > user-space is neither safe nor useful. An approach established by
> > REUSEPORT_SOCKARRAY is to return a socket cookie (a unique identifier)
> > instead.
> >
> > Since socket cookies are u64 values SOCKMAP needs to support such a value
> > size for lookup to be possible. This requires special handling on update,
> > though. Attempts to do a lookup on SOCKMAP holding u32 values will be met
> > with ENOSPC error.
> >
> > Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
> > ---
[...]
> > +static void *sock_map_lookup_sys(struct bpf_map *map, void *key)
> > +{
> > + struct sock *sk;
> > +
> > + WARN_ON_ONCE(!rcu_read_lock_held());
> It seems unnecessary. It is only called by syscall.c which
> holds the rcu_read_lock(). Other than that,
>
+1 drop it. The normal rcu annotations/splats should catch anything here.
> Acked-by: Martin KaFai Lau <kafai@fb.com>
next prev parent reply other threads:[~2020-01-14 3:16 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 10:50 [PATCH bpf-next v2 00/11] Extend SOCKMAP to store listening sockets Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 01/11] bpf, sk_msg: Don't reset saved sock proto on restore Jakub Sitnicki
2020-01-11 22:50 ` John Fastabend
2020-01-10 10:50 ` [PATCH bpf-next v2 02/11] net, sk_msg: Annotate lockless access to sk_prot on clone Jakub Sitnicki
2020-01-11 23:14 ` John Fastabend
2020-01-13 15:09 ` Jakub Sitnicki
2020-01-14 3:14 ` John Fastabend
2020-01-20 17:00 ` John Fastabend
2020-01-20 18:11 ` Jakub Sitnicki
2020-01-21 12:42 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 03/11] net, sk_msg: Clear sk_user_data pointer on clone if tagged Jakub Sitnicki
2020-01-11 23:38 ` John Fastabend
2020-01-12 12:55 ` kbuild test robot
2020-01-13 20:15 ` Martin Lau
2020-01-14 16:04 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 04/11] tcp_bpf: Don't let child socket inherit parent protocol ops on copy Jakub Sitnicki
2020-01-11 2:42 ` kbuild test robot
2020-01-11 3:02 ` kbuild test robot
2020-01-11 23:48 ` John Fastabend
2020-01-13 22:31 ` Jakub Sitnicki
2020-01-13 22:23 ` Martin Lau
2020-01-13 22:42 ` Jakub Sitnicki
2020-01-13 23:23 ` Martin Lau
2020-01-10 10:50 ` [PATCH bpf-next v2 05/11] bpf, sockmap: Allow inserting listening TCP sockets into sockmap Jakub Sitnicki
2020-01-11 23:59 ` John Fastabend
2020-01-13 15:48 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 06/11] bpf, sockmap: Don't set up sockmap progs for listening sockets Jakub Sitnicki
2020-01-12 0:51 ` John Fastabend
2020-01-12 1:07 ` John Fastabend
2020-01-13 17:59 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 07/11] bpf, sockmap: Return socket cookie on lookup from syscall Jakub Sitnicki
2020-01-12 0:56 ` John Fastabend
2020-01-13 23:12 ` Martin Lau
2020-01-14 3:16 ` John Fastabend [this message]
2020-01-14 15:48 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 08/11] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 09/11] bpf: Allow selecting reuseport socket from a SOCKMAP Jakub Sitnicki
2020-01-12 1:00 ` John Fastabend
2020-01-13 23:45 ` Martin Lau
2020-01-15 12:41 ` Jakub Sitnicki
2020-01-13 23:51 ` Martin Lau
2020-01-15 12:57 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 10/11] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP Jakub Sitnicki
2020-01-12 1:01 ` John Fastabend
2020-01-10 10:50 ` [PATCH bpf-next v2 11/11] selftests/bpf: Tests for SOCKMAP holding listening sockets Jakub Sitnicki
2020-01-12 1:06 ` John Fastabend
2020-01-13 15:58 ` Jakub Sitnicki
2020-01-11 0:18 ` [PATCH bpf-next v2 00/11] Extend SOCKMAP to store " Alexei Starovoitov
2020-01-11 22:47 ` John Fastabend
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