Hi Günter,
On Fri, May 20, 2022 at 4:52 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
On 5/20/22 07:32, Geert Uytterhoeven wrote:
The macros implementing Atari ROM port I/O writes do not cast away their
output, unlike similar implementations for other I/O buses.
When they are combined using conditional expressions in the definitions of
outb() and friends, this triggers sparse warnings like:
drivers/net/appletalk/cops.c:382:17: error: incompatible types in conditional expression (different base types):
drivers/net/appletalk/cops.c:382:17: unsigned char
drivers/net/appletalk/cops.c:382:17: void
Fix this by adding casts to "void".
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Thanks!
Removing the casts instead causes issues with functions propagating void
return values (return expression in void function), which BTW sparse
complains about, too.
We live and learn. I didn't even know that this was valid syntax.
I knew about the syntax, but didn't realize immediately why it was
done that way.
Initially I thought it was some relic from the "always cast to void
to make it clear you do not care about the return value"-frenzy, which
are inside Linux visible mostly in the various "(void)acpi_<foo>(...);"
calls. AFAIK these are checked by some external tools.
In Linux, we have __must_check to annotate the important cases.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
