Commit 98868668 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

bpf: Abstract away entire bpf_link clean up procedure 



Instead of requiring users to do three steps for cleaning up bpf_link, its
anon_inode file, and unused fd, abstract that away into bpf_link_cleanup()
helper. bpf_link_defunct() is removed, as it shouldn't be needed as an
individual operation anymore.

v1->v2:
- keep bpf_link_cleanup() static for now (Daniel).

Signed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200313002128.2028680-1-andriin@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 4cd729fa

include/linux/bpf.h

+0 −1
Original line number Diff line number Diff line
@@ -1075,7 +1075,6 @@ struct bpf_link_ops { 


void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops,

		   struct bpf_prog *prog);

void bpf_link_defunct(struct bpf_link *link);

void bpf_link_inc(struct bpf_link *link);

void bpf_link_put(struct bpf_link *link);

int bpf_link_new_fd(struct bpf_link *link);

kernel/bpf/syscall.c

+11 −7
Original line number Diff line number Diff line
@@ -2188,9 +2188,17 @@ void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops, 
	link->prog = prog;

}



void bpf_link_defunct(struct bpf_link *link)

/* Clean up bpf_link and corresponding anon_inode file and FD. After

 * anon_inode is created, bpf_link can't be just kfree()'d due to deferred

 * anon_inode's release() call. This helper manages marking bpf_link as

 * defunct, releases anon_inode file and puts reserved FD.

 */

static void bpf_link_cleanup(struct bpf_link *link, struct file *link_file,

			     int link_fd)

{

	link->prog = NULL;

	fput(link_file);

	put_unused_fd(link_fd);

}



void bpf_link_inc(struct bpf_link *link)
@@ -2383,9 +2391,7 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog) 


	err = bpf_trampoline_link_prog(prog);

	if (err) {

		bpf_link_defunct(&link->link);

		fput(link_file);

		put_unused_fd(link_fd);

		bpf_link_cleanup(&link->link, link_file, link_fd);

		goto out_put_prog;

	}
@@ -2498,9 +2504,7 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr) 


	err = bpf_probe_register(link->btp, prog);

	if (err) {

		bpf_link_defunct(&link->link);

		fput(link_file);

		put_unused_fd(link_fd);

		bpf_link_cleanup(&link->link, link_file, link_fd);

		goto out_put_btp;

	}

CRA Git | Maintained and supported by SUSTech CRA and CCSE