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Fri, 23 Apr 2021 04:00:39 -0400 Received: from mail-vs1-xe2f.google.com (mail-vs1-xe2f.google.com [IPv6:2607:f8b0:4864:20::e2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65E40C06174A for ; Fri, 23 Apr 2021 01:00:01 -0700 (PDT) Received: by mail-vs1-xe2f.google.com with SMTP id w24so292351vsq.5 for ; Fri, 23 Apr 2021 01:00:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pmtAlemk9SkQiMZDpYGCeEcDtc4HAQA190oHucpZ6SI=; b=GxfOAh/M/OMPoZSX6vx3Y/rchiyiDt/hPaZ5VKds+a9vdawKMk+Hmy5u/asG8VI3LO we3/vg/JR9S0cIilK4a4sOuOE6wjMP/nDaQJkB1m/icFjhCxVvOcUd5ch0mrAEIMbpZz vtoZdDvHo5JeD6bmQT03VXdw4A+iSH4q5BRQWzPEtSy79W2Sixw4baXFX/jHtnoGdrit G+y8ubozgRrzmU7v22jIkAqlNIVmnfXrWvQf+AkAEX/YjqjPtnhvaXQLK163f8NG8i1j 50EqzRglaKnOArkqsYhHouaDe48OxH4koVEZadnoa7fPuGnOj1S3C6NUq8i4gy7I0x30 SS8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pmtAlemk9SkQiMZDpYGCeEcDtc4HAQA190oHucpZ6SI=; b=h6HiR77nJgQRritvIjIV/U015X4FfJ/EH/d4CHA9lucV2qEG/wCj4ixfNcrAqyRct3 r41GX36NcPuL0ruGlxouI/FfIJbdNZm3x5TkLTy6dv7v48EF1aNYWy6TGS+lr+jhQC4/ wbX/OA65fTdrUOdrSIDvvOW5Nkg8SMETuHnT0kcbcYooJcXq6wg93NCNbxSczXgCo1EO pmHiLWCzH0cS5xpQmpeB9fzXsj97XlVPGA3O0Pli4bZ7e1RHTtKOUluw46u4FYZ3kEmX Z1z+yPVXHGYM06AnQ+7dsDbJdfI3DKD/9YVANkVbl1RuwFc8PQolwG7e/5bTm5cytDou UztQ== X-Gm-Message-State: AOAM533pLJm0AYyQ/HwwIM0G+nZFbcwiaAVj4tHfwjMgF8IkyPr1N0VM MkLmpBd6Bsn8hb09UGrUaaHL9ulj7tlTwbt+cKO4bg== X-Google-Smtp-Source: ABdhPJw1eb9lAuquyTjGTAeDhOqfXxVOUgDPREXGno3kNAY+lV6q3CImbRpUTYs6UqoM7kV4bUn3Ho8EuYgbNwIiYy8= X-Received: by 2002:a67:e902:: with SMTP id c2mr2022417vso.42.1619164800544; Fri, 23 Apr 2021 01:00:00 -0700 (PDT) MIME-Version: 1.0 References: <20210421135215.3414589-1-arnd@kernel.org> In-Reply-To: <20210421135215.3414589-1-arnd@kernel.org> From: Ulf Hansson Date: Fri, 23 Apr 2021 09:59:24 +0200 Message-ID: Subject: Re: [PATCH] memstick: r592: ignore kfifo_out() return code again 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@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Apr 2021 at 15:52, Arnd Bergmann wrote: > > From: Arnd Bergmann > > 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 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 >