Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 2 Jul 2021 12:42:57 -0700 | Subject | Re: [GIT PULL 1/2] asm-generic: rework PCI I/O space access |
| |
On Fri, Jul 2, 2021 at 6:48 AM Arnd Bergmann <arnd@kernel.org> wrote: > > A rework for PCI I/O space access from Niklas Schnelle:
I pulled this, but then I ended up unpulling.
I don't absolutely _hate_ the concept, but I really find this to be very unpalatable:
#if !defined(inb) && !defined(_inb) #define _inb _inb static inline u8 _inb(unsigned long addr) { #ifdef PCI_IOBASE u8 val;
__io_pbr(); val = __raw_readb(PCI_IOBASE + addr); __io_par(val); return val; #else WARN_ONCE(1, "No I/O port support\n"); return ~0; #endif } #endif
because honestly, the notion of a run-time warning for a compile-time "this cannot work" is just wrong.
If the platform doesn't have inb/outb, and you compile some driver that uses them, you don't want a run-time warning. Particularly since in many cases nobody will ever run it, and the main use case was to do compile-testing across a wide number of platforms.
So if the platform doesn't have inb/outb, they simply should not be declared, and there should be a *compile-time* error. That is literally a lot more useful, and it avoids this extra code.
Extra code that not only doesn't add value, but that actually *subtracts* value is not code I really want to pull.
Linus
| |