[bpf,v2,1/2] bpf: simplify definition of BPF_FIB_LOOKUP related flags
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Message ID 20190612160541.2550-1-m@lambda.lt
State Accepted
Delegated to: BPF Maintainers
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Series
  • [bpf,v2,1/2] bpf: simplify definition of BPF_FIB_LOOKUP related flags
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Commit Message

Martynas Pumputis June 12, 2019, 4:05 p.m. UTC
Previously, the BPF_FIB_LOOKUP_{DIRECT,OUTPUT} flags were defined
with the help of BIT macro. This had the following issues:

- In order to user 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.

Signed-off-by: Martynas Pumputis <m@lambda.lt>
---
 include/uapi/linux/bpf.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Andrii Nakryiko June 13, 2019, 6:43 a.m. UTC | #1
On Wed, Jun 12, 2019 at 11:06 AM Martynas Pumputis <m@lambda.lt> wrote:
>
> Previously, the BPF_FIB_LOOKUP_{DIRECT,OUTPUT} flags were defined
> with the help of BIT macro. This had the following issues:
>
> - In order to user 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.
>

Makes sense!

Acked-by: Andrii Nakryiko <andriin@fb.com>

> Signed-off-by: Martynas Pumputis <m@lambda.lt>
> ---
>  include/uapi/linux/bpf.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 63e0cf66f01a..a8f17bc86732 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -3376,8 +3376,8 @@ 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 */
> --
> 2.21.0
>
Daniel Borkmann June 13, 2019, 8:48 p.m. UTC | #2
On 06/12/2019 06:05 PM, Martynas Pumputis wrote:
> Previously, the BPF_FIB_LOOKUP_{DIRECT,OUTPUT} flags were defined
> with the help of BIT macro. This had the following issues:
> 
> - In order to user 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.
> 
> Signed-off-by: Martynas Pumputis <m@lambda.lt>

Applied, thanks!

Patch
diff mbox series

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 63e0cf66f01a..a8f17bc86732 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3376,8 +3376,8 @@  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 */