On (03/21/19 08:49), Stanislav Fomichev wrote: > On 03/21, Sergey Senozhatsky wrote: > > On (03/20/19 20:24), Alexei Starovoitov wrote: > > > On Wed, Mar 20, 2019 at 09:53:33PM +0900, Sergey Senozhatsky wrote: > > > > Not all compilers have __builtin_bswap16() and __builtin_bswap32(), > > > > thus not all compilers are able to compile the following code: > > > > > > > > (__builtin_constant_p(x) ? \ > > > > ___constant_swab16(x) : __builtin_bswap16(x)) > > > > > > > > That's the reason why bpf_ntohl() doesn't work on GCC < 4.8, for > > > > instance: > > > > > > nack to fixes to support such old compilers. > > > > Fair enough. > What is too old? Documentation/process/changes.rst says that minimum > supported gcc is 4.6, do we lift that requirement for the tests? Hmm, good point, Stanislav. I thought it was gcc 4.9 which introduced asm goto and hence 4.9 is the minimum supported version. But it seems that it was 4.5/4.6, so the min supported gcc version is 4.6. Which means that those bpf defines won't work on some compilers. Alexei, does your NACK still stand? -ss