selftests/bpf: Export map_update_retriable()

Export map_update_retriable() to make it usable for other map_test
cases. These cases may only need retry for specific errno, so add
a new callback parameter to let map_update_retriable() decide whether or
not the errno is retriable.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231101032455.3808547-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Add test result messages for test_task_storage_map_stress_lookup

Add test result message when test_task_storage_map_stress_lookup()
succeeds or is skipped. The test case can be skipped due to the choose
of preemption model in kernel config, so export skips in test_maps.c and
increase it when needed.

The following is the output of test_maps when the test case succeeds or
is skipped:

test_task_storage_map_stress_lookup:PASS
test_maps: OK, 0 SKIPPED

test_task_storage_map_stress_lookup SKIP (no CONFIG_PREEMPT)
test_maps: OK, 1 SKIPPED

Fixes: 73b97bc78b32 ("selftests/bpf: Test concurrent updates on bpf_task_storage_busy")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20220919035714.2195144-1-houtao@huaweicloud.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

bpf: Add BPF_MAP_TYPE_SK_STORAGE test to test_maps

This patch adds BPF_MAP_TYPE_SK_STORAGE test to test_maps.
The src file is rather long, so it is put into another dir map_tests/
and compile like the current prog_tests/ does. Other existing
tests in test_maps can also be re-factored into map_tests/ in the
future.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>