* [PATCH] memstick: r592: ignore kfifo_out() return code again
@ 2021-04-21 13:51 Arnd Bergmann
2021-04-21 17:16 ` Nick Desaulniers
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Arnd Bergmann @ 2021-04-21 13:51 UTC (permalink / raw)
To: Maxim Levitsky, Alex Dubov, Ulf Hansson
Cc: Arnd Bergmann, Nathan Chancellor, Nick Desaulniers,
Jing Xiangfeng, Jiapeng Chong, linux-mmc, linux-kernel,
clang-built-linux
From: Arnd Bergmann <arnd@arndb.de>
A minor cleanup to address a clang warning removed an assigned
but unused local variable, but this now caused a gcc warning as
kfifo_out() is annotated to require checking its return code:
In file included from drivers/memstick/host/r592.h:13,
from drivers/memstick/host/r592.c:21:
drivers/memstick/host/r592.c: In function 'r592_flush_fifo_write':
include/linux/kfifo.h:588:1: error: ignoring return value of '__kfifo_uint_must_check_helper' declared with attribute 'warn_unused_result' [-Werror=unused-result]
588 | __kfifo_uint_must_check_helper( \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
589 | ({ \
| ~~~~
590 | typeof((fifo) + 1) __tmp = (fifo); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
591 | typeof(__tmp->ptr) __buf = (buf); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
592 | unsigned long __n = (n); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~
593 | const size_t __recsize = sizeof(*__tmp->rectype); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
594 | struct __kfifo *__kfifo = &__tmp->kfifo; \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
595 | (__recsize) ?\
| ~~~~~~~~~~~~~~
596 | __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
597 | __kfifo_out(__kfifo, __buf, __n); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
598 | }) \
| ~~~~
599 | )
| ~
drivers/memstick/host/r592.c:367:9: note: in expansion of macro 'kfifo_out'
367 | kfifo_out(&dev->pio_fifo, buffer, 4);
| ^~~~~~~~~
The value was never checked here, and the purpose of the function
is only to flush the contents, so restore the old behavior but
add a cast to void and a comment, which hopefully warns with neither
gcc nor clang now.
If anyone has an idea for how to fix it without ignoring the return
code, that is probably better.
Fixes: 4b00ed3c5072 ("memstick: r592: remove unused variable")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/memstick/host/r592.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/memstick/host/r592.c b/drivers/memstick/host/r592.c
index 026fadaa1d5d..615a83782e55 100644
--- a/drivers/memstick/host/r592.c
+++ b/drivers/memstick/host/r592.c
@@ -359,12 +359,15 @@ static void r592_write_fifo_pio(struct r592_device *dev,
/* Flushes the temporary FIFO used to make aligned DWORD writes */
static void r592_flush_fifo_write(struct r592_device *dev)
{
+ int ret;
u8 buffer[4] = { 0 };
if (kfifo_is_empty(&dev->pio_fifo))
return;
- kfifo_out(&dev->pio_fifo, buffer, 4);
+ ret = kfifo_out(&dev->pio_fifo, buffer, 4);
+ /* intentionally ignore __must_check return code */
+ (void)ret;
r592_write_reg_raw_be(dev, R592_FIFO_PIO, *(u32 *)buffer);
}
--
2.29.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] memstick: r592: ignore kfifo_out() return code again
2021-04-21 13:51 [PATCH] memstick: r592: ignore kfifo_out() return code again Arnd Bergmann
@ 2021-04-21 17:16 ` Nick Desaulniers
2021-04-21 19:27 ` Arnd Bergmann
2021-04-23 7:59 ` Ulf Hansson
2021-04-26 9:44 ` Ulf Hansson
2 siblings, 1 reply; 5+ messages in thread
From: Nick Desaulniers @ 2021-04-21 17:16 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Maxim Levitsky, Alex Dubov, Ulf Hansson, Arnd Bergmann,
Nathan Chancellor, Jing Xiangfeng, Jiapeng Chong, linux-mmc,
LKML, clang-built-linux
On Wed, Apr 21, 2021 at 6:52 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> A minor cleanup to address a clang warning removed an assigned
> but unused local variable, but this now caused a gcc warning as
> kfifo_out() is annotated to require checking its return code:
>
> In file included from drivers/memstick/host/r592.h:13,
> from drivers/memstick/host/r592.c:21:
> drivers/memstick/host/r592.c: In function 'r592_flush_fifo_write':
> include/linux/kfifo.h:588:1: error: ignoring return value of '__kfifo_uint_must_check_helper' declared with attribute 'warn_unused_result' [-Werror=unused-result]
> 588 | __kfifo_uint_must_check_helper( \
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 589 | ({ \
> | ~~~~
> 590 | typeof((fifo) + 1) __tmp = (fifo); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 591 | typeof(__tmp->ptr) __buf = (buf); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 592 | unsigned long __n = (n); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~
> 593 | const size_t __recsize = sizeof(*__tmp->rectype); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 594 | struct __kfifo *__kfifo = &__tmp->kfifo; \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 595 | (__recsize) ?\
> | ~~~~~~~~~~~~~~
> 596 | __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 597 | __kfifo_out(__kfifo, __buf, __n); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 598 | }) \
> | ~~~~
> 599 | )
> | ~
> drivers/memstick/host/r592.c:367:9: note: in expansion of macro 'kfifo_out'
> 367 | kfifo_out(&dev->pio_fifo, buffer, 4);
> | ^~~~~~~~~
>
> The value was never checked here, and the purpose of the function
> is only to flush the contents, so restore the old behavior but
> add a cast to void and a comment, which hopefully warns with neither
> gcc nor clang now.
>
> If anyone has an idea for how to fix it without ignoring the return
> code, that is probably better.
Should r592_flush_fifo_write be made to return an int, then callers of
r592_flush_fifo_write percolate up their return code?
r592_transfer_fifo_pio() seems to only return 0, but its callers are
doing return code checking.
>
> Fixes: 4b00ed3c5072 ("memstick: r592: remove unused variable")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/memstick/host/r592.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/memstick/host/r592.c b/drivers/memstick/host/r592.c
> index 026fadaa1d5d..615a83782e55 100644
> --- a/drivers/memstick/host/r592.c
> +++ b/drivers/memstick/host/r592.c
> @@ -359,12 +359,15 @@ static void r592_write_fifo_pio(struct r592_device *dev,
> /* Flushes the temporary FIFO used to make aligned DWORD writes */
> static void r592_flush_fifo_write(struct r592_device *dev)
> {
> + int ret;
> u8 buffer[4] = { 0 };
>
> if (kfifo_is_empty(&dev->pio_fifo))
> return;
>
> - kfifo_out(&dev->pio_fifo, buffer, 4);
> + ret = kfifo_out(&dev->pio_fifo, buffer, 4);
> + /* intentionally ignore __must_check return code */
> + (void)ret;
> r592_write_reg_raw_be(dev, R592_FIFO_PIO, *(u32 *)buffer);
> }
>
> --
> 2.29.2
>
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] memstick: r592: ignore kfifo_out() return code again
2021-04-21 17:16 ` Nick Desaulniers
@ 2021-04-21 19:27 ` Arnd Bergmann
0 siblings, 0 replies; 5+ messages in thread
From: Arnd Bergmann @ 2021-04-21 19:27 UTC (permalink / raw)
To: Nick Desaulniers
Cc: Maxim Levitsky, Alex Dubov, Ulf Hansson, Nathan Chancellor,
Jing Xiangfeng, Jiapeng Chong, linux-mmc, LKML,
clang-built-linux
On Wed, Apr 21, 2021 at 7:17 PM 'Nick Desaulniers' via Clang Built
Linux <clang-built-linux@googlegroups.com> wrote:
> On Wed, Apr 21, 2021 at 6:52 AM Arnd Bergmann <arnd@kernel.org> wrote:
> > The value was never checked here, and the purpose of the function
> > is only to flush the contents, so restore the old behavior but
> > add a cast to void and a comment, which hopefully warns with neither
> > gcc nor clang now.
> >
> > If anyone has an idea for how to fix it without ignoring the return
> > code, that is probably better.
>
> Should r592_flush_fifo_write be made to return an int, then callers of
> r592_flush_fifo_write percolate up their return code?
> r592_transfer_fifo_pio() seems to only return 0, but its callers are
> doing return code checking.
I looked into that but couldn't come up with anything useful to do with
the return code in the callers. kfifo_out() itself doesn't seem to
ever return an error but only the length.
Arnd
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] memstick: r592: ignore kfifo_out() return code again
2021-04-21 13:51 [PATCH] memstick: r592: ignore kfifo_out() return code again Arnd Bergmann
2021-04-21 17:16 ` Nick Desaulniers
@ 2021-04-23 7:59 ` Ulf Hansson
2021-04-26 9:44 ` Ulf Hansson
2 siblings, 0 replies; 5+ messages in thread
From: Ulf Hansson @ 2021-04-23 7:59 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Maxim Levitsky, Alex Dubov, Arnd Bergmann, Nathan Chancellor,
Nick Desaulniers, Jing Xiangfeng, Jiapeng Chong, linux-mmc,
Linux Kernel Mailing List, clang-built-linux
On Wed, 21 Apr 2021 at 15:52, Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> A minor cleanup to address a clang warning removed an assigned
> but unused local variable, but this now caused a gcc warning as
> kfifo_out() is annotated to require checking its return code:
>
> In file included from drivers/memstick/host/r592.h:13,
> from drivers/memstick/host/r592.c:21:
> drivers/memstick/host/r592.c: In function 'r592_flush_fifo_write':
> include/linux/kfifo.h:588:1: error: ignoring return value of '__kfifo_uint_must_check_helper' declared with attribute 'warn_unused_result' [-Werror=unused-result]
> 588 | __kfifo_uint_must_check_helper( \
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 589 | ({ \
> | ~~~~
> 590 | typeof((fifo) + 1) __tmp = (fifo); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 591 | typeof(__tmp->ptr) __buf = (buf); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 592 | unsigned long __n = (n); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~
> 593 | const size_t __recsize = sizeof(*__tmp->rectype); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 594 | struct __kfifo *__kfifo = &__tmp->kfifo; \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 595 | (__recsize) ?\
> | ~~~~~~~~~~~~~~
> 596 | __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 597 | __kfifo_out(__kfifo, __buf, __n); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 598 | }) \
> | ~~~~
> 599 | )
> | ~
> drivers/memstick/host/r592.c:367:9: note: in expansion of macro 'kfifo_out'
> 367 | kfifo_out(&dev->pio_fifo, buffer, 4);
> | ^~~~~~~~~
>
> The value was never checked here, and the purpose of the function
> is only to flush the contents, so restore the old behavior but
> add a cast to void and a comment, which hopefully warns with neither
> gcc nor clang now.
>
> If anyone has an idea for how to fix it without ignoring the return
> code, that is probably better.
Perhaps, if you can't do anything with return value, why is kfifo_out
declared like this?
>
> Fixes: 4b00ed3c5072 ("memstick: r592: remove unused variable")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Kind regards
Uffe
> ---
> drivers/memstick/host/r592.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/memstick/host/r592.c b/drivers/memstick/host/r592.c
> index 026fadaa1d5d..615a83782e55 100644
> --- a/drivers/memstick/host/r592.c
> +++ b/drivers/memstick/host/r592.c
> @@ -359,12 +359,15 @@ static void r592_write_fifo_pio(struct r592_device *dev,
> /* Flushes the temporary FIFO used to make aligned DWORD writes */
> static void r592_flush_fifo_write(struct r592_device *dev)
> {
> + int ret;
> u8 buffer[4] = { 0 };
>
> if (kfifo_is_empty(&dev->pio_fifo))
> return;
>
> - kfifo_out(&dev->pio_fifo, buffer, 4);
> + ret = kfifo_out(&dev->pio_fifo, buffer, 4);
> + /* intentionally ignore __must_check return code */
> + (void)ret;
> r592_write_reg_raw_be(dev, R592_FIFO_PIO, *(u32 *)buffer);
> }
>
> --
> 2.29.2
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] memstick: r592: ignore kfifo_out() return code again
2021-04-21 13:51 [PATCH] memstick: r592: ignore kfifo_out() return code again Arnd Bergmann
2021-04-21 17:16 ` Nick Desaulniers
2021-04-23 7:59 ` Ulf Hansson
@ 2021-04-26 9:44 ` Ulf Hansson
2 siblings, 0 replies; 5+ messages in thread
From: Ulf Hansson @ 2021-04-26 9:44 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Maxim Levitsky, Alex Dubov, Arnd Bergmann, Nathan Chancellor,
Nick Desaulniers, Jing Xiangfeng, Jiapeng Chong, linux-mmc,
Linux Kernel Mailing List, clang-built-linux
On Wed, 21 Apr 2021 at 15:52, Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> A minor cleanup to address a clang warning removed an assigned
> but unused local variable, but this now caused a gcc warning as
> kfifo_out() is annotated to require checking its return code:
>
> In file included from drivers/memstick/host/r592.h:13,
> from drivers/memstick/host/r592.c:21:
> drivers/memstick/host/r592.c: In function 'r592_flush_fifo_write':
> include/linux/kfifo.h:588:1: error: ignoring return value of '__kfifo_uint_must_check_helper' declared with attribute 'warn_unused_result' [-Werror=unused-result]
> 588 | __kfifo_uint_must_check_helper( \
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 589 | ({ \
> | ~~~~
> 590 | typeof((fifo) + 1) __tmp = (fifo); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 591 | typeof(__tmp->ptr) __buf = (buf); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 592 | unsigned long __n = (n); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~
> 593 | const size_t __recsize = sizeof(*__tmp->rectype); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 594 | struct __kfifo *__kfifo = &__tmp->kfifo; \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 595 | (__recsize) ?\
> | ~~~~~~~~~~~~~~
> 596 | __kfifo_out_r(__kfifo, __buf, __n, __recsize) : \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 597 | __kfifo_out(__kfifo, __buf, __n); \
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 598 | }) \
> | ~~~~
> 599 | )
> | ~
> drivers/memstick/host/r592.c:367:9: note: in expansion of macro 'kfifo_out'
> 367 | kfifo_out(&dev->pio_fifo, buffer, 4);
> | ^~~~~~~~~
>
> The value was never checked here, and the purpose of the function
> is only to flush the contents, so restore the old behavior but
> add a cast to void and a comment, which hopefully warns with neither
> gcc nor clang now.
>
> If anyone has an idea for how to fix it without ignoring the return
> code, that is probably better.
>
> Fixes: 4b00ed3c5072 ("memstick: r592: remove unused variable")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Applied for next, thanks!
Kind regards
Uffe
> ---
> drivers/memstick/host/r592.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/memstick/host/r592.c b/drivers/memstick/host/r592.c
> index 026fadaa1d5d..615a83782e55 100644
> --- a/drivers/memstick/host/r592.c
> +++ b/drivers/memstick/host/r592.c
> @@ -359,12 +359,15 @@ static void r592_write_fifo_pio(struct r592_device *dev,
> /* Flushes the temporary FIFO used to make aligned DWORD writes */
> static void r592_flush_fifo_write(struct r592_device *dev)
> {
> + int ret;
> u8 buffer[4] = { 0 };
>
> if (kfifo_is_empty(&dev->pio_fifo))
> return;
>
> - kfifo_out(&dev->pio_fifo, buffer, 4);
> + ret = kfifo_out(&dev->pio_fifo, buffer, 4);
> + /* intentionally ignore __must_check return code */
> + (void)ret;
> r592_write_reg_raw_be(dev, R592_FIFO_PIO, *(u32 *)buffer);
> }
>
> --
> 2.29.2
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2021-04-21 13:51 [PATCH] memstick: r592: ignore kfifo_out() return code again Arnd Bergmann
2021-04-21 17:16 ` Nick Desaulniers
2021-04-21 19:27 ` Arnd Bergmann
2021-04-23 7:59 ` Ulf Hansson
2021-04-26 9:44 ` Ulf Hansson
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