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Commit 59d3656d authored by Brenden Blanco's avatar Brenden Blanco Committed by David S. Miller
Browse files

bpf: add bpf_prog_add api for bulk prog refcnt 



A subsystem may need to store many copies of a bpf program, each
deserving its own reference. Rather than requiring the caller to loop
one by one (with possible mid-loop failure), add a bulk bpf_prog_add
api.

Signed-off-by: default avatarBrenden Blanco <bblanco@plumgrid.com>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ddbcb794

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -224,6 +224,7 @@ void bpf_register_map_type(struct bpf_map_type_list *tl); 


struct bpf_prog *bpf_prog_get(u32 ufd);

struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type);

struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i);

struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);

void bpf_prog_put(struct bpf_prog *prog);

kernel/bpf/syscall.c

+9 −3
Original line number Diff line number Diff line
@@ -670,14 +670,20 @@ static struct bpf_prog *____bpf_prog_get(struct fd f) 
	return f.file->private_data;

}



struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)

struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i)

{

	if (atomic_inc_return(&prog->aux->refcnt) > BPF_MAX_REFCNT) {

		atomic_dec(&prog->aux->refcnt);

	if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) {

		atomic_sub(i, &prog->aux->refcnt);

		return ERR_PTR(-EBUSY);

	}

	return prog;

}

EXPORT_SYMBOL_GPL(bpf_prog_add);



struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)

{

	return bpf_prog_add(prog, 1);

}



static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type)

{