[v3,bpf-next,0/2] Sleepable local storage

Message

KP Singh Dec. 24, 2021, 3:29 p.m. UTC

Local storage is currently unusable in sleepable helpers. One of the
important use cases of local_storage is to attach security (or
performance) contextual information to kernel objects in LSM / tracing
programs to be used later in the life-cyle of the object.

Sometimes this context can only be gathered from sleepable programs
(because it needs accesing __user pointers or helpers like
bpf_ima_inode_hash). Allowing local storage to be used from sleepable
programs allows such context to be managed with the benefits of
local_storage.

# v2 -> v3

* Fixed some RCU issues pointed by Martin
* Added Martin's ack

# v1 -> v2

* Generalize RCU checks (will send a separate patch for updating
  non local storage code where this can be used).
* Add missing RCU lock checks from v1


KP Singh (2):
  bpf: Allow bpf_local_storage to be used by sleepable programs
  bpf/selftests: Update local storage selftest for sleepable programs

 include/linux/bpf_local_storage.h             |  5 ++
 kernel/bpf/bpf_inode_storage.c                |  6 ++-
 kernel/bpf/bpf_local_storage.c                | 50 ++++++++++++++-----
 kernel/bpf/bpf_task_storage.c                 |  6 ++-
 kernel/bpf/verifier.c                         |  3 ++
 net/core/bpf_sk_storage.c                     |  8 ++-
 .../bpf/prog_tests/test_local_storage.c       | 20 +++-----
 .../selftests/bpf/progs/local_storage.c       | 24 ++-------
 8 files changed, 73 insertions(+), 49 deletions(-)

Comments

Alexei Starovoitov Dec. 30, 2021, 2:02 a.m. UTC | #1

On Fri, Dec 24, 2021 at 03:29:14PM +0000, KP Singh wrote:
> Local storage is currently unusable in sleepable helpers. One of the
> important use cases of local_storage is to attach security (or
> performance) contextual information to kernel objects in LSM / tracing
> programs to be used later in the life-cyle of the object.
> 
> Sometimes this context can only be gathered from sleepable programs
> (because it needs accesing __user pointers or helpers like
> bpf_ima_inode_hash). Allowing local storage to be used from sleepable
> programs allows such context to be managed with the benefits of
> local_storage.
> 
> # v2 -> v3
> 
> * Fixed some RCU issues pointed by Martin
> * Added Martin's ack

Applied, Thanks