On Tue, Feb 24, 2009 at 4:03 PM, Sam Ravnborg <sam@xxxxxxxxxxxx> wrote: > On Tue, Feb 24, 2009 at 02:05:25PM -0500, Fred Isaman wrote: >> The pnfs tree base of of 2.6.29-rc5 uses the new find_last_bit >> function (defined in >> lib/find_last_bit.c) in a file in the fs/nfs directory. Myself and >> another developer (though no one else so far) get the following error >> during compile: >> >> Kernel: arch/x86/boot/bzImage is ready (#5) >> Building modules, stage 2. >> MODPOST 515 modules >> ERROR: "find_last_bit" [fs/nfs/nfs.ko] undefined! >> make[2]: *** [__modpost] Error 1 >> make[1]: *** [modules] Error 2 >> make: *** [sub-make] Error 2 >> >> >> Note that find_last_bit() is not used in any file in the fs directory. >> If I add it to any function that is EXPORT_SYMBOL'ed >> from the fs directory, suddenly the compile errors go away. (See the >> below patch for a more concrete example.) >> >> I am not sure what is going on, and why it only affects some >> developers, but it looks a lot like the kbuild system >> is deciding that the library does not need to be included at the fs >> directory level, so isn't including it in fs/nfs where >> it is needed. > > kbuild only links in libaries if there is any users of siad library. > And your normal config has no users of lib/find_last_bit.c so > it is not linked into the kernel. > I don't understand your comment. There *is* a user of the library in the (modified) fs/nfs/nfs4proc.c. The problem is that it doesn't compile unless there is also a user in some fs/*.c. > The general rule is that if any in tree module uses a library > then the library is always linked in. > And to always link in a library you need to patch the Makefile > as Randy suggest in his mail. > > Sam > Again, I suspect I am misunderstanding. It seems you are suggesting that to compile the nfs code I have to alter lib/Makefile. While that is a useful workaround, that is certainly not a viable solution. Fred -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
