From c9985d09e18965131958102f4b67fa1e742df335 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Thu, 20 Aug 2020 12:00:58 -0700 Subject: [PATCH] bpf: sock_ops: Change some members of sock_ops_kern from u32 to u8 A later 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 later patch can still fit everything in a cacheline. Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200820190058.2885640-1-kafai@fb.com --- 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 0a355b005bf4..c427dfa5f908 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 075ab71b985c..1608f4b3987f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -8465,17 +8465,22 @@ 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);