bpf: add BPF_SIZEOF and BPF_FIELD_SIZEOF macros

Add BPF_SIZEOF() and BPF_FIELD_SIZEOF() macros to improve the code a bit
which otherwise often result in overly long bytes_to_bpf_size(sizeof())
and bytes_to_bpf_size(FIELD_SIZEOF()) lines. So place them into a macro
helper instead. Moreover, we currently have a BUILD_BUG_ON(BPF_FIELD_SIZEOF())
check in convert_bpf_extensions(), but we should rather make that generic
as well and add a BUILD_BUG_ON() test in all BPF_SIZEOF()/BPF_FIELD_SIZEOF()
users to detect any rewriter size issues at compile time. Note, there are
currently none, but we want to assert that it stays this way.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 6 deletions

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d3869b03d9fe..e63d7d435796 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -583,18 +583,18 @@ static u32 pe_prog_convert_ctx_access(enum bpf_access_type type, int dst_reg,
         switch (ctx_off) {
         case offsetof(struct bpf_perf_event_data, sample_period):
                 BUILD_BUG_ON(FIELD_SIZEOF(struct perf_sample_data, period) != sizeof(u64));
-                *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct bpf_perf_event_data_kern, data)),
-                                      dst_reg, src_reg,
+
+                *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
+                                                       data), dst_reg, src_reg,
                                       offsetof(struct bpf_perf_event_data_kern, data));
                 *insn++ = BPF_LDX_MEM(BPF_DW, dst_reg, dst_reg,
                                       offsetof(struct perf_sample_data, period));
                 break;
         default:
-                *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct bpf_perf_event_data_kern, regs)),
-                                      dst_reg, src_reg,
+                *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
+                                                       regs), dst_reg, src_reg,
                                       offsetof(struct bpf_perf_event_data_kern, regs));
-                *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(sizeof(long)),
-                                      dst_reg, dst_reg, ctx_off);
+                *insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), dst_reg, dst_reg, ctx_off);
                 break;
         }