Messages in this thread | | | Subject | Re: [PATCH 34/36] tty: serial: pmac_zilog: Make disposable variable __always_unused | From | Jiri Slaby <> | Date | Thu, 5 Nov 2020 08:39:56 +0100 |
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On 05. 11. 20, 8:04, Christophe Leroy wrote: > > > Le 04/11/2020 à 20:35, Lee Jones a écrit : >> Fixes the following W=1 kernel build warning(s): >> >> drivers/tty/serial/pmac_zilog.h:365:58: warning: variable ‘garbage’ >> set but not used [-Wunused-but-set-variable] > > Explain how you are fixing this warning. > > Setting __always_unused is usually not the good solution for fixing > this warning, but here I guess this is likely the good solution. But it > should be explained why.
Or, why is the "garbage =" needed in the first place? read_zsdata is not defined with __warn_unused_result__. And even if it was, would (void)!read_zsdata(port) fix it?
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> Cc: Jiri Slaby <jirislaby@kernel.org> >> Cc: Michael Ellerman <mpe@ellerman.id.au> >> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> >> Cc: Paul Mackerras <paulus@samba.org> >> Cc: linux-serial@vger.kernel.org >> Cc: linuxppc-dev@lists.ozlabs.org >> Signed-off-by: Lee Jones <lee.jones@linaro.org> >> --- >> drivers/tty/serial/pmac_zilog.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/tty/serial/pmac_zilog.h >> b/drivers/tty/serial/pmac_zilog.h >> index bb874e76810e0..968aec7c1cf82 100644 >> --- a/drivers/tty/serial/pmac_zilog.h >> +++ b/drivers/tty/serial/pmac_zilog.h >> @@ -362,7 +362,7 @@ static inline void zssync(struct uart_pmac_port >> *port) >> /* Misc macros */ >> #define ZS_CLEARERR(port) (write_zsreg(port, 0, ERR_RES)) >> -#define ZS_CLEARFIFO(port) do { volatile unsigned char garbage; \ >> +#define ZS_CLEARFIFO(port) do { volatile unsigned char >> __always_unused garbage; \ >> garbage = read_zsdata(port); \ >> garbage = read_zsdata(port); \ >> garbage = read_zsdata(port); \ >>
thanks, -- js
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