Steven Rostedt <rostedt@xxxxxxxxxxx> writes: > On Fri, 09 Jun 2017 20:53:53 +0200 > Paul Bolle <pebolle@xxxxxxxxxx> wrote: > >> On Fri, 2017-06-09 at 14:32 -0400, Steven Rostedt wrote: >> > I'm sure it works, but it just adds one more way of doing the same >> > thing. I thought that was what perl was always criticized for, and why >> > people usually prefer python. Don't get me wrong, I prefer oysters over >> > snakes. But I just wanted to point out the lack of consistency here. >> >> A major benefit is that >> #if IS_ENABLED(CONFIG_HYPERV) >> >> is shorter than >> #if defined(CONFIG_HYPERV) || defined(CONFIG_HYPERV_MODULE) >> >> and less prone to typos. >> > > I don't believe the module version is needed here. Otherwise I would > question the #if altogether. Which now I'm looking at it, why is it > needed? > > What includes this header file that wouldn't have that set anyway? The > only place it is included is in: > > arch/x86/hyperv/mmu.c > > Is that compiled without CONFIG_HYPERV? No, it is not but as was already mentioned it is valid and common to have CONFIG_HYPERV=m (we should've probably done things differently in the past; CONFIG_HYPERV=y/n should've been used for indicating Hyper-V support and something like CONFIG_HYPERV_VMBUS=y/m/n to say if we want to have vmbus as a module but...). arch/x86/hyperv/mmu.c is compiled in vmlinux when CONFIG_HYPERV is enabled in any way, this is updated in PATCH8 of this series: diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild index 586b786..3e6f640 100644 --- a/arch/x86/Kbuild +++ b/arch/x86/Kbuild @@ -8,7 +8,7 @@ obj-$(CONFIG_KVM) += kvm/ obj-$(CONFIG_XEN) += xen/ # Hyper-V paravirtualization support -obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/ +obj-$(subst m,y,$(CONFIG_HYPERV)) += hyperv/ # lguest paravirtualization support obj-$(CONFIG_LGUEST_GUEST) += lguest/ (it was Andy who suggested we use 'subst', not me :-) So we can't just change IS_ENABLED -> ifdef in this patch. We can, of course, write " #if defined(CONFIG_HYPERV) || defined(CONFIG_HYPERV_MODULE)" but we were replacing it with IF_ENABLED in the past, not sure we should do that. Dropping the #if altogether is possible, but why having it when CONFIG_HYPERV=n? -- Vitaly _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
