linux-stable.git/tools/testing/selftests/bpf/progs/mmap_inner_array.c, branch linux-rolling-stable Linux kernel stable tree selftests/bpf: Add a test for mmap-able map in map 2024-07-29T22:05:04+00:00 Song Liu song@kernel.org 2024-07-23T05:14:55+00:00 c7db4873fbd63918c124a5d67182492c78ba705b Regular BPF hash map is not mmap-able from user space. However, map-in-map with outer map of type BPF_MAP_TYPE_HASH_OF_MAPS and mmap-able array as inner map can perform similar operations as a mmap-able hash map. This can be used by applications that benefit from fast accesses to some local data. Add a selftest to show this use case. Signed-off-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20240723051455.1589192-1-song@kernel.org Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> 
Regular BPF hash map is not mmap-able from user space. However, map-in-map
with outer map of type BPF_MAP_TYPE_HASH_OF_MAPS and mmap-able array as
inner map can perform similar operations as a mmap-able hash map. This
can be used by applications that benefit from fast accesses to some local
data.

Add a selftest to show this use case.

Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240723051455.1589192-1-song@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>