On Thu, Oct 11, 2018 at 05:36:36PM -0500, Eric Sandeen wrote: > > > On 10/11/18 2:59 PM, Brian Norris wrote: > > On Wed, Oct 10, 2018 at 03:55:32PM -0500, Eric Sandeen wrote: > >> Brian Norris reported that "The $BUILD_CC toolchain might have an > >> older set of Linux headers than the $CC toolchain. It's generally > >> unsafe to try to build both with the same definitions, but in > >> particular, this one can cause compilation failures in the local > >> crc32selftest build: [failure to find fsmap.h]" > >> > >> It seems like the most straightforward thing to do here is include > >> a specific set of system headers, instead of pulling in the whole > >> xfs.h header chain which has multiple tests and definitions in > >> place for headers that may or may not be there during the build. > >> > >> Reported-by: Brian Norris <briannorris@xxxxxxxxxxxx> > >> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > >> --- > >> > >> Brian, here's try #3, does this also work for you? > > > > Tested-by: Brian Norris <briannorris@xxxxxxxxxxxx> > > > > This still leaves $BUILD_CFLAGS with bad entries, but as long as they > > don't get used anywhere that matters, it'll be OK. > > Thanks. At this point I think you have a better grasp of what all the > $FOO_FLAGS do than I do ;) It may be to keep things sorted > and separate, but it also seemed useful to get a giant tangle of > xfs header out of a non-xfs library file. > > I'm also on the fence about whether cross-compiling the self-check > really even gains us much, given that it may be built or optimized > completely differently from the code on the target arch ... So long as it's a software algorithm with a big lookup table I guess it's a serviceable sanity check that nobody totally goobered up the source code, but I don't know if it adds much value in the cross compilation case either. If you ever wanted to add a faster implementation in the built libxfs <cough> that would be more of an issue. (Granted, I've been running a patched xfsprogs with hw accelerated crc32c for a year now and haven't noticed any difference in runtime. Maybe now that I've finished upgrading everything to flash...) --D > -Eric
