diff options
| author | Song Liu <song@kernel.org> | 2025-06-22 23:38:52 -0700 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-07-02 14:18:20 +0200 |
| commit | b95ee9049c93b05da66599d6e0d1fcfea291360b (patch) | |
| tree | 38f0ba9d91654eb4c114ee2ca030349ba297cc2e /kernel | |
| parent | fb7b30cb0e31bce904b4ec6a20e863351f9fee82 (diff) | |
bpf: Introduce bpf_cgroup_read_xattr to read xattr of cgroup's node
BPF programs, such as LSM and sched_ext, would benefit from tags on
cgroups. One common practice to apply such tags is to set xattrs on
cgroupfs folders.
Introduce kfunc bpf_cgroup_read_xattr, which allows reading cgroup's
xattr.
Note that, we already have bpf_get_[file|dentry]_xattr. However, these
two APIs are not ideal for reading cgroupfs xattrs, because:
1) These two APIs only works in sleepable contexts;
2) There is no kfunc that matches current cgroup to cgroupfs dentry.
bpf_cgroup_read_xattr is generic and can be useful for many program
types. It is also safe, because it requires trusted or rcu protected
argument (KF_RCU). Therefore, we make it available to all program types.
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/20250623063854.1896364-3-song@kernel.org
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/helpers.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index b71e428ad936..9ff1b4090289 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3397,6 +3397,9 @@ BTF_ID_FLAGS(func, bpf_iter_dmabuf_next, KF_ITER_NEXT | KF_RET_NULL | KF_SLEEPAB BTF_ID_FLAGS(func, bpf_iter_dmabuf_destroy, KF_ITER_DESTROY | KF_SLEEPABLE) #endif BTF_ID_FLAGS(func, __bpf_trap) +#ifdef CONFIG_CGROUPS +BTF_ID_FLAGS(func, bpf_cgroup_read_xattr, KF_RCU) +#endif BTF_KFUNCS_END(common_btf_ids) static const struct btf_kfunc_id_set common_kfunc_set = { |