Commit 93ac9b15 authored by Tejun Heo's avatar Tejun Heo
Browse files

tools/sched_ext/include: Add libbpf version guard for assoc_struct_ops 



Extract the inline bpf_program__assoc_struct_ops() call in SCX_OPS_LOAD()
into a __scx_ops_assoc_prog() helper and wrap it with a libbpf >= 1.7
version guard. bpf_program__assoc_struct_ops() was added in libbpf 1.7;
the guard provides a no-op fallback for older versions. Add the
<bpf/libbpf.h> include needed by the helper, and fix "assumming" typo in
a nearby comment.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarAndrea Righi <arighi@nvidia.com>
parent c9c8546c

tools/sched_ext/include/scx/compat.h

+29 −6
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#define __SCX_COMPAT_H



#include <bpf/btf.h>

#include <bpf/libbpf.h>

#include <fcntl.h>

#include <stdlib.h>

#include <unistd.h>
@@ -182,6 +183,31 @@ static inline long scx_hotplug_seq(void) 
	__skel; 								\

})



/*

 * Associate non-struct_ops BPF programs with the scheduler's struct_ops map so

 * that scx_prog_sched() can determine which scheduler a BPF program belongs

 * to. Requires libbpf >= 1.7.

 */

#if LIBBPF_MAJOR_VERSION > 1 ||							\

	(LIBBPF_MAJOR_VERSION == 1 && LIBBPF_MINOR_VERSION >= 7)

static inline void __scx_ops_assoc_prog(struct bpf_program *prog,

					struct bpf_map *map,

					const char *ops_name)

{

	s32 err = bpf_program__assoc_struct_ops(prog, map, NULL);

	if (err)

		fprintf(stderr,

			"ERROR: Failed to associate %s with %s: %d\n",

			bpf_program__name(prog), ops_name, err);

}

#else

static inline void __scx_ops_assoc_prog(struct bpf_program *prog,

					struct bpf_map *map,

					const char *ops_name)

{

}

#endif



#define SCX_OPS_LOAD(__skel, __ops_name, __scx_name, __uei_name) ({		\

	struct bpf_program *__prog;						\

	UEI_SET_SIZE(__skel, __ops_name, __uei_name);				\
@@ -189,18 +215,15 @@ static inline long scx_hotplug_seq(void) 
	bpf_object__for_each_program(__prog, (__skel)->obj) {			\

		if (bpf_program__type(__prog) == BPF_PROG_TYPE_STRUCT_OPS)	\

			continue;						\

		s32 err = bpf_program__assoc_struct_ops(__prog,			\

					(__skel)->maps.__ops_name, NULL);	\

		if (err)							\

			fprintf(stderr, "ERROR: Failed to associate %s with %s: %d\n", \

				bpf_program__name(__prog), #__ops_name, err);	\

		__scx_ops_assoc_prog(__prog, (__skel)->maps.__ops_name,		\

				     #__ops_name);				\

	}									\

})



/*

 * New versions of bpftool now emit additional link placeholders for BPF maps,

 * and set up BPF skeleton in such a way that libbpf will auto-attach BPF maps

 * automatically, assumming libbpf is recent enough (v1.5+). Old libbpf will do

 * automatically, assuming libbpf is recent enough (v1.5+). Old libbpf will do

 * nothing with those links and won't attempt to auto-attach maps.

 *

 * To maintain compatibility with older libbpf while avoiding trying to attach