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From: Nathan Chancellor <natechancellor@gmail.com>
To: "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>
Cc: 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>,
	Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH] xsk: Properly terminate assignment in xskq_produce_flush_desc
Date: Tue, 25 Jun 2019 11:23:52 -0700	[thread overview]
Message-ID: <20190625182352.13918-1-natechancellor@gmail.com> (raw)

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>
---
 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


             reply	other threads:[~2019-06-25 18:24 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-25 18:23 Nathan Chancellor [this message]
2019-06-25 18:32 ` Nick Desaulniers
2019-06-25 19:46 ` Jonathan Lemon
2019-06-25 20:49   ` Björn Töpel
2019-06-26  1:13 ` Song Liu
2019-06-26 14:30 ` Daniel Borkmann

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