From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: "Martin KaFai Lau" <kafai@fb.com>,
"Hangbin Liu" <liuhangbin@gmail.com>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Magnus Karlsson" <magnus.karlsson@gmail.com>,
"Paul E . McKenney" <paulmck@kernel.org>,
"Jakub Kicinski" <kuba@kernel.org>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Jassi Brar" <jaswinder.singh@linaro.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>
Subject: [PATCH bpf-next v4 17/19] netsec: remove rcu_read_lock() around XDP program invocation
Date: Wed, 23 Jun 2021 13:07:25 +0200 [thread overview]
Message-ID: <20210623110727.221922-18-toke@redhat.com> (raw)
In-Reply-To: <20210623110727.221922-1-toke@redhat.com>
The netsec driver has a rcu_read_lock()/rcu_read_unlock() pair around the
full RX loop, covering everything up to and including xdp_do_flush(). This
is actually the correct behaviour, but because it all happens in a single
NAPI poll cycle (and thus under local_bh_disable()), it is also technically
redundant.
With the addition of RCU annotations to the XDP_REDIRECT map types that
take bh execution into account, lockdep even understands this to be safe,
so there's really no reason to keep the rcu_read_lock() around anymore, so
let's just remove it.
Cc: Jassi Brar <jaswinder.singh@linaro.org>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
drivers/net/ethernet/socionext/netsec.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
index dfc85cc68173..20d148c019d8 100644
--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -958,7 +958,6 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
xdp_init_buff(&xdp, PAGE_SIZE, &dring->xdp_rxq);
- rcu_read_lock();
xdp_prog = READ_ONCE(priv->xdp_prog);
dma_dir = page_pool_get_dma_dir(dring->page_pool);
@@ -1069,8 +1068,6 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
}
netsec_finalize_xdp_rx(priv, xdp_act, xdp_xmit);
- rcu_read_unlock();
-
return done;
}
--
2.32.0
next prev parent reply other threads:[~2021-06-23 11:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 11:07 [PATCH bpf-next v4 00/19] Clean up and document RCU-based object protection for XDP and TC BPF Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 01/19] rcu: Create an unrcu_pointer() to remove __rcu from a pointer Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 02/19] doc: Clarify and expand RCU updaters and corresponding readers Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 03/19] doc: Give XDP as example of non-obvious RCU reader/updater pairing Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 04/19] bpf: allow RCU-protected lookups to happen from bh context Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 05/19] xdp: add proper __rcu annotations to redirect map entries Toke Høiland-Jørgensen
2021-06-24 13:12 ` Daniel Borkmann
2021-06-24 14:52 ` Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 06/19] sched: remove unneeded rcu_read_lock() around BPF program invocation Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 07/19] ena: remove rcu_read_lock() around XDP " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 08/19] bnxt: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 09/19] thunderx: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 10/19] freescale: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 11/19] net: intel: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 12/19] marvell: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 13/19] mlx4: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 14/19] nfp: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 15/19] qede: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 16/19] sfc: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` Toke Høiland-Jørgensen [this message]
2021-06-23 11:07 ` [PATCH bpf-next v4 18/19] stmmac: " Toke Høiland-Jørgensen
2021-06-23 11:07 ` [PATCH bpf-next v4 19/19] net: ti: " Toke Høiland-Jørgensen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210623110727.221922-18-toke@redhat.com \
--to=toke@redhat.com \
--cc=bpf@vger.kernel.org \
--cc=brouer@redhat.com \
--cc=ilias.apalodimas@linaro.org \
--cc=jaswinder.singh@linaro.org \
--cc=kafai@fb.com \
--cc=kuba@kernel.org \
--cc=liuhangbin@gmail.com \
--cc=magnus.karlsson@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=paulmck@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).