Re: [PATCH RFC v2] m68k: remove get_fs()/set_fs()

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Christoph,

Am 08.07.2021 um 16:31 schrieb Christoph Hellwig:
> On Wed, Jul 07, 2021 at 08:01:33PM -0700, Linus Torvalds wrote:
>> The '#' turns the argument into a string, but it was already
>> _supposed_ to be a string. But no, the problem is that it turns the
>> macro name MOVES into the _string_ "MOVES".
>>
>> Which happens to compile just fine, because "moves" is a real
>> instruction. But it's actually _meant_ to be a macro that expands to
>> either the string "moves" or "move".
>>
>> So what happens is that at least in Christoph's version, I think the
>> code _always_ uses "MOVES", even in configurations where the macro
>> MOVES should have just become "move".
>>
>> So it all builds fine, looks fine to the assembler, but it uses the
>> wrong instruction.
>>
>> Macro expansion with the '#' character and other macros used as
>> arguments is something people need to be very careful with.  It's why
>> we have a whole header file for just the "stringify" operation, see
>> <linux/stringify.h>
>>
>> But in this case, it shouldn't have used '#' at all, since the
>> argument was already a string, and never needed to be turned into a
>> string by the pre-processor.
>
> Yes, that problem exists, but just removing the # causes "inst" to go
> into the cpp output.  Let me brush up my cpp-foo.

Putting quotes around 'inst' makes it compile for me.

Cheers,

	Michael