Commit b0e4701c authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann
Browse files

bpf: export bpf_map_inc_not_zero 



Rename existing bpf_map_inc_not_zero to __bpf_map_inc_not_zero to
indicate that it's caller's responsibility to do proper locking.
Create and export bpf_map_inc_not_zero wrapper that properly
locks map_idr_lock. Will be used in the next commit to
hold a map while cloning a socket.

Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent fae55527

include/linux/bpf.h

+2 −0
Original line number Diff line number Diff line
@@ -647,6 +647,8 @@ void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock); 
struct bpf_map *bpf_map_get_with_uref(u32 ufd);

struct bpf_map *__bpf_map_get(struct fd f);

struct bpf_map * __must_check bpf_map_inc(struct bpf_map *map, bool uref);

struct bpf_map * __must_check bpf_map_inc_not_zero(struct bpf_map *map,

						   bool uref);

void bpf_map_put_with_uref(struct bpf_map *map);

void bpf_map_put(struct bpf_map *map);

int bpf_map_charge_memlock(struct bpf_map *map, u32 pages);

kernel/bpf/syscall.c

+13 −3
Original line number Diff line number Diff line
@@ -683,7 +683,7 @@ struct bpf_map *bpf_map_get_with_uref(u32 ufd) 
}



/* map_idr_lock should have been held */

static struct bpf_map *bpf_map_inc_not_zero(struct bpf_map *map,

static struct bpf_map *__bpf_map_inc_not_zero(struct bpf_map *map,

					      bool uref)

{

	int refold;
@@ -704,6 +704,16 @@ static struct bpf_map *bpf_map_inc_not_zero(struct bpf_map *map, 
	return map;

}



struct bpf_map *bpf_map_inc_not_zero(struct bpf_map *map, bool uref)

{

	spin_lock_bh(&map_idr_lock);

	map = __bpf_map_inc_not_zero(map, uref);

	spin_unlock_bh(&map_idr_lock);



	return map;

}

EXPORT_SYMBOL_GPL(bpf_map_inc_not_zero);



int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)

{

	return -ENOTSUPP;
@@ -2177,7 +2187,7 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr) 
	spin_lock_bh(&map_idr_lock);

	map = idr_find(&map_idr, id);

	if (map)

		map = bpf_map_inc_not_zero(map, true);

		map = __bpf_map_inc_not_zero(map, true);

	else

		map = ERR_PTR(-ENOENT);

	spin_unlock_bh(&map_idr_lock);

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