From: Jason Wang <jasowang@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: "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: Re: [PATCH] vhost: silence an unused-variable warning
Date: Thu, 7 Mar 2019 11:00:19 +0800 [thread overview]
Message-ID: <6b55ea04-72d7-6130-e29e-977c4afad0b5@redhat.com> (raw)
In-Reply-To: <20190306110602.2529137-1-arnd@arndb.de>
On 2019/3/6 下午7:05, Arnd Bergmann wrote:
> 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,
Acked-by: Jason Wang <jasowang@redhat.com>
next prev parent reply other threads:[~2019-03-07 3:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-06 11:05 [PATCH] vhost: silence an unused-variable warning Arnd Bergmann
2019-03-07 3:00 ` Jason Wang [this message]
2019-03-08 23:17 ` David Miller
2019-03-09 23:19 ` Michael S. Tsirkin
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