Commit 8ec3bf5c authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Martin KaFai Lau
Browse files

bpf: Add bpf_guard_preempt() convenience macro 



Add bpf_guard_preempt() macro that uses newly introduced
bpf_preempt_disable/enable() kfuncs to guard a critical section.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20240424225529.16782-1-alexei.starovoitov@gmail.com


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent 52578f7f

tools/testing/selftests/bpf/bpf_experimental.h

+22 −0
Original line number Diff line number Diff line
@@ -397,6 +397,28 @@ l_true: \ 
		     , [as]"i"((dst_as << 16) | src_as));

#endif



void bpf_preempt_disable(void) __weak __ksym;

void bpf_preempt_enable(void) __weak __ksym;



typedef struct {

} __bpf_preempt_t;



static inline __bpf_preempt_t __bpf_preempt_constructor(void)

{

	__bpf_preempt_t ret = {};



	bpf_preempt_disable();

	return ret;

}

static inline void __bpf_preempt_destructor(__bpf_preempt_t *t)

{

	bpf_preempt_enable();

}

#define bpf_guard_preempt() \

	__bpf_preempt_t ___bpf_apply(preempt, __COUNTER__)			\

	__attribute__((__unused__, __cleanup__(__bpf_preempt_destructor))) =	\

	__bpf_preempt_constructor()



/* Description

 *	Assert that a conditional expression is true.

 * Returns

tools/testing/selftests/bpf/progs/preempt_lock.c

+2 −5
Original line number Diff line number Diff line
@@ -3,9 +3,7 @@ 
#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "bpf_misc.h"



void bpf_preempt_disable(void) __ksym;

void bpf_preempt_enable(void) __ksym;

#include "bpf_experimental.h"



SEC("?tc")

__failure __msg("1 bpf_preempt_enable is missing")
@@ -92,8 +90,7 @@ static __noinline void preempt_balance_subprog(void) 
SEC("?tc")

__success int preempt_balance(struct __sk_buff *ctx)

{

	bpf_preempt_disable();

	bpf_preempt_enable();

	bpf_guard_preempt();

	return 0;

}