From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
<daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH bpf-next] bpf: abstract away entire bpf_link clean up procedure
Date: Thu, 12 Mar 2020 13:39:14 -0700 [thread overview]
Message-ID: <20200312203914.1195762-1-andriin@fb.com> (raw)
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.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
include/linux/bpf.h | 3 ++-
kernel/bpf/syscall.c | 18 +++++++++++-------
2 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 4fd91b7c95ea..358f3eb07c01 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1075,7 +1075,8 @@ 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_cleanup(struct bpf_link *link, struct file *link_file,
+ int link_fd);
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);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b2f73ecacced..d2f49ae225b0 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -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.
+ */
+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;
}
--
2.17.1
next reply other threads:[~2020-03-12 20:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-12 20:39 Andrii Nakryiko [this message]
2020-03-12 23:22 ` [PATCH bpf-next] bpf: abstract away entire bpf_link clean up procedure Daniel Borkmann
2020-03-12 23:27 ` Andrii Nakryiko
2020-03-12 23:41 ` Daniel Borkmann
2020-03-12 23:47 ` Andrii Nakryiko
2020-03-12 23:38 ` Martin KaFai Lau
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200312203914.1195762-1-andriin@fb.com \
--to=andriin@fb.com \
--cc=andrii.nakryiko@gmail.com \
--cc=ast@fb.com \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=kernel-team@fb.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).