From: Hou Tao <houtao1@huawei.com>
To: Alexei Starovoitov <ast@kernel.org>,
John Fastabend <john.fastabend@gmail.com>
Cc: Martin KaFai Lau <kafai@fb.com>, Yonghong Song <yhs@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Brendan Jackman <jackmanb@google.com>, <netdev@vger.kernel.org>,
<bpf@vger.kernel.org>, <houtao1@huawei.com>
Subject: [PATCH bpf-next] bpf, x86: remove unnecessary handling of BPF_SUB atomic op
Date: Thu, 27 Jan 2022 16:32:40 +0800 [thread overview]
Message-ID: <20220127083240.1425481-1-houtao1@huawei.com> (raw)
According to the LLVM commit (https://reviews.llvm.org/D72184),
sync_fetch_and_sub() is implemented as a negation followed by
sync_fetch_and_add(), so there will be no BPF_SUB op and just
remove it.
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
arch/x86/net/bpf_jit_comp.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index ce1f86f245c9..5d643ebb1e56 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -787,7 +787,6 @@ static int emit_atomic(u8 **pprog, u8 atomic_op,
/* emit opcode */
switch (atomic_op) {
case BPF_ADD:
- case BPF_SUB:
case BPF_AND:
case BPF_OR:
case BPF_XOR:
--
2.29.2
next reply other threads:[~2022-01-27 8:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-27 8:32 Hou Tao [this message]
2022-01-27 10:48 ` [PATCH bpf-next] bpf, x86: remove unnecessary handling of BPF_SUB atomic op Brendan Jackman
2022-01-27 21:51 ` Daniel Borkmann
2022-01-28 2:40 ` John Fastabend
2022-01-27 21:50 ` patchwork-bot+netdevbpf
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=20220127083240.1425481-1-houtao1@huawei.com \
--to=houtao1@huawei.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=jackmanb@google.com \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=yhs@fb.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.