[PATCH bpf-next 0/2] s390/bpf: Remove the orig_call NULL check

[Ilya Leoshkevich <iii@linux.ibm.com>]

Hi,

I've been looking at fixing the tailcall_bpf2bpf_hierarchy failures on
s390. One of the challenges is that when a BPF trampoline calls a BPF
prog A, the prologue of A sets the tail call count to 0. Therefore it
would be useful to know whether the trampoline is attached to some
other BPF prog B, in which case A should be called using an offset
equal to tail_call_start, bypassing the tail call count initialization.

The trampoline attachment point is passed to trampoline functions via
the orig_call variable. Unfortunately in the case of calculating the
size of a struct_ops trampoline it's NULL, and I could not think of a
good reason to have it this way. This series makes it always non-NULL.

Best regards,
Ilya

Ilya Leoshkevich (2):
  bpf: Pass the same orig_call value to trampoline functions
  s390/bpf: Remove the orig_call NULL check

 arch/s390/net/bpf_jit_comp.c | 5 ++---
 kernel/bpf/bpf_struct_ops.c  | 2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

-- 
2.49.0