Commit cc487558 authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
Browse files

bpf: Add zero_map_value to zero map value with special fields 



We need this helper to skip over special fields (bpf_spin_lock,
bpf_timer, kptrs) while zeroing a map value. Use the same logic as
copy_map_value but memset instead of memcpy.

Currently, the code zeroing map value memory does not have to deal with
special fields, hence this is a prerequisite for introducing such
support.

Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220904204145.3089-4-memxor@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 6df4ea1f

include/linux/bpf.h

+19 −0
Original line number Diff line number Diff line
@@ -329,6 +329,25 @@ static inline void copy_map_value_long(struct bpf_map *map, void *dst, void *src 
	__copy_map_value(map, dst, src, true);

}



static inline void zero_map_value(struct bpf_map *map, void *dst)

{

	u32 curr_off = 0;

	int i;



	if (likely(!map->off_arr)) {

		memset(dst, 0, map->value_size);

		return;

	}



	for (i = 0; i < map->off_arr->cnt; i++) {

		u32 next_off = map->off_arr->field_off[i];



		memset(dst + curr_off, 0, next_off - curr_off);

		curr_off += map->off_arr->field_sz[i];

	}

	memset(dst + curr_off, 0, map->value_size - curr_off);

}



void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,

			   bool lock_src);

void bpf_timer_cancel_and_free(void *timer);