[PATCH 4.19 62/72] bpf: simplify definition of BPF_FIB_LOOKUP related flags

Greg Kroah-Hartman
2019-07-02T08:12:33Z

From: Martynas Pumputis <m@lambda.lt>

commit b1d6c15b9d824a58c5415673f374fac19e8eccdf upstream.

Previously, the BPF_FIB_LOOKUP_{DIRECT,OUTPUT} flags in the BPF UAPI
were defined with the help of BIT macro. This had the following issues:

- In order to use any of the flags, a user was required to depend
on <linux/bits.h>.
- No other flag in bpf.h uses the macro, so it seems that an unwritten
convention is to use (1 << (nr)) to define BPF-related flags.

Fixes: 87f5fc7e48dd ("bpf: Provide helper to do forwarding lookups in kernel FIB table")
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/uapi/linux/bpf.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2705,8 +2705,8 @@ struct bpf_raw_tracepoint_args {
/* DIRECT: Skip the FIB rules and go to FIB table associated with device
* OUTPUT: Do lookup from egress perspective; default is ingress
*/
-#define BPF_FIB_LOOKUP_DIRECT BIT(0)
-#define BPF_FIB_LOOKUP_OUTPUT BIT(1)
+#define BPF_FIB_LOOKUP_DIRECT (1U << 0)
+#define BPF_FIB_LOOKUP_OUTPUT (1U << 1)

enum {
BPF_FIB_LKUP_RET_SUCCESS, /* lookup successful */