bpf: add comments to BPF ld/ldx sizes

Doc BPF ld/ldx size defines as comments in code, as it makes in
faster to lookup in a programming/review setting, than looking up
the sizes in Documentation/networking/filter.txt.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7c2259e..74dc4dc 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -17,7 +17,7 @@
 #define BPF_ALU64      0x07    /* alu mode in double word width */
 
 /* ld/ldx fields */
-#define BPF_DW         0x18    /* double word */
+#define BPF_DW         0x18    /* double word (64-bit) */
 #define BPF_XADD       0xc0    /* exclusive add */
 
 /* alu/jmp fields */

diff --git a/include/uapi/linux/bpf_common.h b/include/uapi/linux/bpf_common.h
index 18be907..ee97668 100644 (file)
--- a/include/uapi/linux/bpf_common.h
+++ b/include/uapi/linux/bpf_common.h
@@ -15,9 +15,10 @@
 
 /* ld/ldx fields */
 #define BPF_SIZE(code)  ((code) & 0x18)
-#define                BPF_W           0x00
-#define                BPF_H           0x08
-#define                BPF_B           0x10
+#define                BPF_W           0x00 /* 32-bit */
+#define                BPF_H           0x08 /* 16-bit */
+#define                BPF_B           0x10 /*  8-bit */
+/* eBPF                BPF_DW          0x18    64-bit */
 #define BPF_MODE(code)  ((code) & 0xe0)
 #define                BPF_IMM         0x00
 #define                BPF_ABS         0x20