selftests/bpf: Speed up module_attach test

The module_attach test contains subtests which check that unloading a
module while there are BPF programs attached to its functions is not
possible because the module is still referenced.

The problem is that the test calls the generic unload_module() helper
function which is used for module cleanup after test_progs terminate and
tries to wait until all module references are released. This
unnecessarily slows down the module_attach subtests since each
unsuccessful call to unload_module() takes about 1 second.

Introduce try_unload_module() which takes the number of retries as a
parameter. Make unload_module() call it with the currently used amount
of 10000 retries but call it with just 1 retry from module_attach tests
as it is always expected to fail. This speeds up the module_attach()
test significantly.

Before:

    # time ./test_progs -t module_attach
    [...]
    Summary: 1/14 PASSED, 0 SKIPPED, 0 FAILED

    real        0m5.011s
    user        0m0.293s
    sys         0m0.108s

After:

    # time ./test_progs -t module_attach
    [...]
    Summary: 1/14 PASSED, 0 SKIPPED, 0 FAILED

    real        0m0.350s
    user        0m0.197s
    sys         0m0.063s

Signed-off-by: Viktor Malik <vmalik@redhat.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260306101628.3822284-1-vmalik@redhat.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

0 files changed, 0 insertions, 0 deletions