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From: Arnd Bergmann <arnd@arndb.de>
To: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	"David S. Miller" <davem@davemloft.net>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] vhost: silence an unused-variable warning
Date: Wed,  6 Mar 2019 12:05:49 +0100	[thread overview]
Message-ID: <20190306110602.2529137-1-arnd@arndb.de> (raw)

On some architectures, the MMU can be disabled, leading to access_ok()
becoming an empty macro that does not evaluate its size argument,
which in turn produces an unused-variable warning:

drivers/vhost/vhost.c:1191:9: error: unused variable 's' [-Werror,-Wunused-variable]
        size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;

Mark the variable as __maybe_unused to shut up that warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/vhost/vhost.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index a2e5dc7716e2..5ace833de746 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1188,7 +1188,7 @@ static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
 			 struct vring_used __user *used)
 
 {
-	size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
+	size_t s __maybe_unused = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
 
 	return access_ok(desc, num * sizeof *desc) &&
 	       access_ok(avail,
-- 
2.20.0


             reply	other threads:[~2019-03-06 11:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-06 11:05 Arnd Bergmann [this message]
2019-03-07  3:00 ` [PATCH] vhost: silence an unused-variable warning Jason Wang
2019-03-08 23:17 ` David Miller
2019-03-09 23:19   ` Michael S. Tsirkin

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