libbpf_set_strict_mode() checks that the passed mode doesn't contain extra bits for LIBBPF_STRICT_* flags that don't exist yet. It makes it difficult for applications to disable some strict flags as something like "LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS" is rejected by this check and they have to use a rather complicated formula to calculate it.[0] One possibility is to change LIBBPF_STRICT_ALL to only contain the bits of all existing LIBBPF_STRICT_* flags instead of 0xffffffff. However it's not possible because the idea is that applications compiled against older libbpf_legacy.h would still be opting into latest LIBBPF_STRICT_ALL features.[1] The other possibility is to remove that check so something like "LIBBPF_STRICT_ALL & ~LIBBPF_STRICT_MAP_DEFINITIONS" is allowed. It's what this commit does. [0]: https://lore.kernel.org/bpf/20220204220435.301896-1-mauricio@xxxxxxxxxx/ [1]: https://lore.kernel.org/bpf/CAEf4BzaTWa9fELJLh+bxnOb0P1EMQmaRbJVG0L+nXZdy0b8G3Q@xxxxxxxxxxxxxx/ Fixes: 93b8952d223a ("libbpf: deprecate legacy BPF map definitions") Signed-off-by: Mauricio Vásquez <mauricio@xxxxxxxxxx> --- tools/lib/bpf/libbpf.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 81605de8654e..d5bac4ed7023 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -156,14 +156,6 @@ enum libbpf_strict_mode libbpf_mode = LIBBPF_STRICT_NONE; int libbpf_set_strict_mode(enum libbpf_strict_mode mode) { - /* __LIBBPF_STRICT_LAST is the last power-of-2 value used + 1, so to - * get all possible values we compensate last +1, and then (2*x - 1) - * to get the bit mask - */ - if (mode != LIBBPF_STRICT_ALL - && (mode & ~((__LIBBPF_STRICT_LAST - 1) * 2 - 1))) - return errno = EINVAL, -EINVAL; - libbpf_mode = mode; return 0; } -- 2.25.1
