[PATCH bpf-next 03/10] bpf: sock_ops: Change some members of sock_ops_kern from u32 to u8
From: Martin KaFai Lau <hidden>
Date: 2020-06-26 17:55:30
Also in:
bpf
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Martin KaFai Lau, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
A latter patch needs to add a few pointers and a few u8 to sock_ops_kern. Hence, this patch saves some spaces by moving some of the existing members from u32 to u8 so that the latter patch can still fit everything in a cacheline. Signed-off-by: Martin KaFai Lau <redacted> --- include/linux/filter.h | 4 ++-- net/core/filter.c | 15 ++++++++++----- 2 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 259377723603..aae52cbda670 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h@@ -1236,13 +1236,13 @@ struct bpf_sock_addr_kern { struct bpf_sock_ops_kern { struct sock *sk; - u32 op; union { u32 args[4]; u32 reply; u32 replylong[4]; }; - u32 is_fullsock; + u8 op; + u8 is_fullsock; u64 temp; /* temp and everything after is not * initialized to 0 before calling * the BPF program. New fields that
diff --git a/net/core/filter.c b/net/core/filter.c
index 19dbcc8448d8..1dd07972c5c7 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -8355,17 +8355,22 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, return insn - insn_buf; switch (si->off) { - case offsetof(struct bpf_sock_ops, op) ... + case offsetof(struct bpf_sock_ops, op): + *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sock_ops_kern, + op), + si->dst_reg, si->src_reg, + offsetof(struct bpf_sock_ops_kern, op)); + break; + + case offsetof(struct bpf_sock_ops, replylong[0]) ... offsetof(struct bpf_sock_ops, replylong[3]): - BUILD_BUG_ON(sizeof_field(struct bpf_sock_ops, op) != - sizeof_field(struct bpf_sock_ops_kern, op)); BUILD_BUG_ON(sizeof_field(struct bpf_sock_ops, reply) != sizeof_field(struct bpf_sock_ops_kern, reply)); BUILD_BUG_ON(sizeof_field(struct bpf_sock_ops, replylong) != sizeof_field(struct bpf_sock_ops_kern, replylong)); off = si->off; - off -= offsetof(struct bpf_sock_ops, op); - off += offsetof(struct bpf_sock_ops_kern, op); + off -= offsetof(struct bpf_sock_ops, replylong[0]); + off += offsetof(struct bpf_sock_ops_kern, replylong[0]); if (type == BPF_WRITE) *insn++ = BPF_STX_MEM(BPF_W, si->dst_reg, si->src_reg, off);
--
2.24.1