From: "Jonathan Lemon" <jonathan.lemon@gmail.com>
To: "Nathan Chancellor" <natechancellor@gmail.com>
Cc: "Björn Töpel" <bjorn.topel@intel.com>,
"Magnus Karlsson" <magnus.karlsson@intel.com>,
"David S. Miller" <davem@davemloft.net>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Jakub Kicinski" <jakub.kicinski@netronome.com>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"John Fastabend" <john.fastabend@gmail.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
xdp-newbies@vger.kernel.org, linux-kernel@vger.kernel.org,
clang-built-linux@googlegroups.com,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Nathan Huckleberry" <nhuck@google.com>
Subject: Re: [PATCH] xsk: Properly terminate assignment in xskq_produce_flush_desc
Date: Tue, 25 Jun 2019 12:46:02 -0700 [thread overview]
Message-ID: <34F07894-FDE7-44F8-B7F2-E2003D550AD2@gmail.com> (raw)
In-Reply-To: <20190625182352.13918-1-natechancellor@gmail.com>
On 25 Jun 2019, at 11:23, Nathan Chancellor wrote:
> Clang warns:
>
> In file included from net/xdp/xsk_queue.c:10:
> net/xdp/xsk_queue.h:292:2: warning: expression result unused
> [-Wunused-value]
> WRITE_ONCE(q->ring->producer, q->prod_tail);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/compiler.h:284:6: note: expanded from macro 'WRITE_ONCE'
> __u.__val; \
> ~~~ ^~~~~
> 1 warning generated.
>
> The q->prod_tail assignment has a comma at the end, not a semi-colon.
> Fix that so clang no longer warns and everything works as expected.
>
> Fixes: c497176cb2e4 ("xsk: add Rx receive functions and poll support")
> Link: https://github.com/ClangBuiltLinux/linux/issues/544
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Nice find.
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
> ---
> net/xdp/xsk_queue.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
> index 88b9ae24658d..cba4a640d5e8 100644
> --- a/net/xdp/xsk_queue.h
> +++ b/net/xdp/xsk_queue.h
> @@ -288,7 +288,7 @@ static inline void xskq_produce_flush_desc(struct
> xsk_queue *q)
> /* Order producer and data */
> smp_wmb(); /* B, matches C */
>
> - q->prod_tail = q->prod_head,
> + q->prod_tail = q->prod_head;
> WRITE_ONCE(q->ring->producer, q->prod_tail);
> }
>
> --
> 2.22.0
next prev parent reply other threads:[~2019-06-25 19:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 18:23 [PATCH] xsk: Properly terminate assignment in xskq_produce_flush_desc Nathan Chancellor
2019-06-25 18:32 ` Nick Desaulniers
2019-06-25 19:46 ` Jonathan Lemon [this message]
2019-06-25 20:49 ` Björn Töpel
2019-06-26 1:13 ` Song Liu
2019-06-26 14:30 ` Daniel Borkmann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=34F07894-FDE7-44F8-B7F2-E2003D550AD2@gmail.com \
--to=jonathan.lemon@gmail.com \
--cc=ast@kernel.org \
--cc=bjorn.topel@intel.com \
--cc=bpf@vger.kernel.org \
--cc=clang-built-linux@googlegroups.com \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=hawk@kernel.org \
--cc=jakub.kicinski@netronome.com \
--cc=john.fastabend@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=magnus.karlsson@intel.com \
--cc=natechancellor@gmail.com \
--cc=ndesaulniers@google.com \
--cc=netdev@vger.kernel.org \
--cc=nhuck@google.com \
--cc=xdp-newbies@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).