On Tue, Jul 30, 2024 at 12:26 AM Shung-Hsi Yu <shung-hsi.yu@xxxxxxxx> wrote: [...] > That is great to hear and really boost the level of confidence. Though I > did made an update[1] to the patch such that implementation of > negative_bit_floor() is change from > > v &= v >> 1; > v &= v >> 2; > v &= v >> 4; > v &= v >> 8; > v &= v >> 16; > v &= v >> 32; > return v; > > to one that closer resembles tnum_range() > > u8 bits = fls64(~v); /* find most-significant unset bit */ > u64 delta; > > /* special case, needed because 1ULL << 64 is undefined */ > if (bits > 63) > return 0; > > delta = (1ULL << bits) - 1; > return ~delta; > This [1] is indeed the version of the patch that we checked: the one that uses fls and fls64 in negative_bit_floor and negative32_bit_floor . I replied here because you had CCed us in this thread. Note that for checking in Agni, the implementation of fls and fls64 were borrowed from asm-generic [2,3,4]. Having said that, the patch [1] looks good to me. Tested-by: Harishankar Vishwanathan <harishankar.vishwanathan@xxxxxxxxx> [1]: https://lore.kernel.org/bpf/20240719081702.137173-1-shung-hsi.yu@xxxxxxxx/ [2]: https://elixir.bootlin.com/linux/v6.10/source/include/asm-generic/bitops/fls.h#L43 [3]: https://elixir.bootlin.com/linux/v6.10/source/include/asm-generic/bitops/fls64.h#L19 [4]: https://elixir.bootlin.com/linux/v6.10/source/include/asm-generic/bitops/__fls.h#L45
