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bpf: Simplify definition of BPF_FIB_LOOKUP related flags

PATCH Superseded Martynas Pumputis 2 participants 2 messages Jun 12, 2019

Subsystems (3)

v1 of 2 Superseded Latest is v2 →

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#0 lore raw

PATCH 1/1 bpf: Simplify definition of BPF_FIB_LOOKUP related flags

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.

---
 include/uapi/linux/bpf.h       | 4 ++--
 tools/include/uapi/linux/bpf.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)
include/uapi/linux/bpf.h +2 -2
index 63e0cf66f01a..a8f17bc86732 100644
@@ -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 */
tools/include/uapi/linux/bpf.h +2 -2
index 63e0cf66f01a..a8f17bc86732 100644
@@ -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 */
Signature · 1 line
2.21.0
#1 lore raw
Quoted 9 lines · Martynas Pumputis

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.

Quoted 5 lines
---
 include/uapi/linux/bpf.h       | 4 ++--
 tools/include/uapi/linux/bpf.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

Makes sense to me.
Please split it into two patches.
One for kernel uapi and one for user space.
Since user bits are synced to github/libbpf independently.

Quoted 33 lines
include/uapi/linux/bpf.h +2 -2
index 63e0cf66f01a..a8f17bc86732 100644
@@ -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 */
tools/include/uapi/linux/bpf.h +2 -3
index 63e0cf66f01a..a8f17bc86732 100644
@@ -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