On Tue, 22 Dec 2015 19:40:39 +0800 Xunlei Pang <xlpang at redhat.com> wrote: > > Following functions will be used only in kexec_file. Please wrap them in > > CONFIG_KEXEC_FILE. > > > > int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, > > unsigned long buf_len); > > void * __weak arch_kexec_kernel_image_load(struct kimage *image); > > int __weak arch_kimage_file_post_load_cleanup(struct kimage *image); > > int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, > > unsigned long buf_len); > > int __weak arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, > > Elf_Shdr *sechdrs, unsigned int relsec); > > int __weak arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, > > unsigned int relsec); > > Thanks for the comment. > > I noticed this as well, but seems for the function declarations we don't need do this, > since they don't consume the actual space. > > For example, in the include/linux/timekeeping.h > /* > * RTC specific > */ > extern bool timekeeping_rtc_skipsuspend(void); > extern bool timekeeping_rtc_skipresume(void); > > extern void timekeeping_inject_sleeptime64(struct timespec64 *delta); > > also not embraced by the corresponding macros. Yes. If we add the ifdefs then a programming error will be detected at compile time. If we don't add the ifdefs then that error will be detected at link time. So the ifdefs provide a quite small advantage, while making the code harder to read and harder to maintain. I believe that "no ifdefs" is the better side of this tradeoff.
