From: Daniel Colascione <dancol@google.com>
To: joelaf@google.com
Cc: linux-kernel@vger.kernel.org, timmurray@google.com,
netdev@vger.kernel.org,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Lorenzo Colitti <lorenzo@google.com>,
Chenbo Feng <fengc@google.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Alexei Starovoitov <ast@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Daniel Colascione <dancol@google.com>
Subject: [PATCH v3] Add BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES bpf(2) command
Date: Sun, 29 Jul 2018 13:58:35 -0700 [thread overview]
Message-ID: <20180729205835.34850-1-dancol@google.com> (raw)
In-Reply-To: <CAKOZuesQ6GdNTGDFsNi4o8LYzxLBtYZ=Cz4=aZbqqCNia+QFnQ@mail.gmail.com>
BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES waits for the release of all
references to maps active at the instant the
BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES is
issued. BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES waits only for the
expiration of map references obtained by BPF programs from other maps.
The purpose of this command is to provide a means for userspace to
replace a BPF map with another, newer version, then ensure that no
component is still using the "old" map before manipulating the "old"
map in some way.
Signed-off-by: Daniel Colascione <dancol@google.com>
---
include/uapi/linux/bpf.h | 14 ++++++++++++++
kernel/bpf/syscall.c | 13 +++++++++++++
2 files changed, 27 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index b7db3261c62d..ca3cfca76edc 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -75,6 +75,19 @@ struct bpf_lpm_trie_key {
__u8 data[0]; /* Arbitrary size */
};
+/* BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES waits for the release of all
+ * references to maps active at the instant the
+ * BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES is
+ * issued. BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES waits only for the
+ * expiration of map references obtained by BPF programs from
+ * other maps.
+ *
+ * The purpose of this command is to provide a means for userspace to
+ * replace a BPF map with another, newer version, then ensure that no
+ * component is still using the "old" map before manipulating the
+ * "old" map in some way.
+ */
+
/* BPF syscall commands, see bpf(2) man-page for details. */
enum bpf_cmd {
BPF_MAP_CREATE,
@@ -98,6 +111,7 @@ enum bpf_cmd {
BPF_BTF_LOAD,
BPF_BTF_GET_FD_BY_ID,
BPF_TASK_FD_QUERY,
+ BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES,
};
enum bpf_map_type {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a31a1ba0f8ea..bc9a0713f47d 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2274,6 +2274,19 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))
return -EPERM;
+ if (cmd == BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES) {
+ if (uattr != NULL || size != 0)
+ return -EINVAL;
+ err = security_bpf(cmd, NULL, 0);
+ if (err < 0)
+ return err;
+ /* BPF programs always enter a critical section while
+ * they have a map reference outstanding.
+ */
+ synchronize_rcu();
+ return 0;
+ }
+
err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);
if (err)
return err;
--
2.18.0.345.g5c9ce644c3-goog
next parent reply other threads:[~2018-07-29 20:58 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAKOZuesQ6GdNTGDFsNi4o8LYzxLBtYZ=Cz4=aZbqqCNia+QFnQ@mail.gmail.com>
2018-07-29 20:58 ` Daniel Colascione [this message]
2018-07-30 10:04 ` [PATCH v3] Add BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES bpf(2) command Daniel Borkmann
2018-07-30 10:25 ` Daniel Colascione
2018-07-31 0:26 ` Jakub Kicinski
2018-07-31 0:33 ` Daniel Colascione
2018-07-31 0:45 ` Jakub Kicinski
2018-07-31 0:50 ` Daniel Colascione
2018-07-31 1:14 ` Jakub Kicinski
2018-07-31 8:34 ` Daniel Borkmann
2018-07-31 9:36 ` Daniel Colascione
2018-08-10 22:52 ` Alexei Starovoitov
2018-08-14 20:37 ` Daniel Colascione
2018-08-16 4:01 ` Alexei Starovoitov
2018-10-12 10:54 ` [PATCH v4] Wait for running BPF programs when updating map-in-map Daniel Colascione
2018-10-12 20:54 ` Joel Fernandes
2018-10-13 2:31 ` Alexei Starovoitov
2018-10-16 17:39 ` Joel Fernandes
2018-10-18 15:46 ` Alexei Starovoitov
2018-10-18 23:36 ` Joel Fernandes
2018-11-10 2:01 ` Chenbo Feng
2018-11-10 15:22 ` Greg KH
2018-11-10 18:58 ` Chenbo Feng
[not found] ` <CAKOZues6SE_c=ix7ap6QaJHqd1TmYpWWMJiu3=TtuqgKuqOUCA@mail.gmail.com>
2018-08-10 22:29 ` [PATCH v3] Add BPF_SYNCHRONIZE_MAP_TO_MAP_REFERENCES bpf(2) command Alexei Starovoitov
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