[PATCH] memstick: r592: ignore kfifo_out() return code again

From: Arnd Bergmann
Date: Wed Apr 21 2021 - 09:52:28 EST


From: Arnd Bergmann <arnd@xxxxxxxx>

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@xxxxxxxx>
---
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