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| author | Tejun Heo <tj@kernel.org> | 2023-02-22 15:29:12 -1000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-02-23 08:33:05 -0800 |
| commit | 332ea1f697be148bd5e66475d82b5ecc5084da65 (patch) | |
| tree | 91c5b5b1138cc7fd1d210dfbaa161af0c9e0054e /Documentation/bpf | |
| parent | 746ce767128598711a00d8df5713d4c3b3d9e9a7 (diff) | |
| download | lwn-332ea1f697be148bd5e66475d82b5ecc5084da65.tar.gz lwn-332ea1f697be148bd5e66475d82b5ecc5084da65.zip | |
bpf: Add bpf_cgroup_from_id() kfunc
cgroup ID is an userspace-visible 64bit value uniquely identifying a given
cgroup. As the IDs are used widely, it's useful to be able to look up the
matching cgroups. Add bpf_cgroup_from_id().
v2: Separate out selftest into its own patch as suggested by Alexei.
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/Y/bBaG96t0/gQl9/@slm.duckdns.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'Documentation/bpf')
| -rw-r--r-- | Documentation/bpf/kfuncs.rst | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index ca96ef3f6896..226313747be5 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -583,13 +583,17 @@ Here's an example of how it can be used: ---- -Another kfunc available for interacting with ``struct cgroup *`` objects is -bpf_cgroup_ancestor(). This allows callers to access the ancestor of a cgroup, -and return it as a cgroup kptr. +Other kfuncs available for interacting with ``struct cgroup *`` objects are +bpf_cgroup_ancestor() and bpf_cgroup_from_id(), allowing callers to access +the ancestor of a cgroup and find a cgroup by its ID, respectively. Both +return a cgroup kptr. .. kernel-doc:: kernel/bpf/helpers.c :identifiers: bpf_cgroup_ancestor +.. kernel-doc:: kernel/bpf/helpers.c + :identifiers: bpf_cgroup_from_id + Eventually, BPF should be updated to allow this to happen with a normal memory load in the program itself. This is currently not possible without more work in the verifier. bpf_cgroup_ancestor() can be used as follows: |