From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heinz Graalfs Subject: [PATCH V2 RFC 7/9] virtio_console: verify if queue is broken after virtqueue_get_buf() Date: Thu, 24 Oct 2013 17:23:18 +0200 Message-ID: <1382628200-42956-8-git-send-email-graalfs@linux.vnet.ibm.com> References: <1382628200-42956-1-git-send-email-graalfs@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1382628200-42956-1-git-send-email-graalfs@linux.vnet.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: rusty@rustcorp.com.au, mst@redhat.com, virtualization@lists.linux-foundation.org Cc: borntraeger@de.ibm.com List-Id: virtualization@lists.linuxfoundation.org If virtqueue_get_buf() returns with a NULL pointer it should be verified if the virtqueue is broken, in order to avoid loop calling cpu_relax(). Signed-off-by: Heinz Graalfs --- drivers/char/virtio_console.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 1b456fe..9dce2f0 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -574,7 +574,8 @@ static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id, spin_lock(&portdev->c_ovq_lock); if (virtqueue_add_outbuf(vq, sg, 1, &cpkt, GFP_ATOMIC) == 0) { virtqueue_kick(vq); - while (!virtqueue_get_buf(vq, &len)) + while (!virtqueue_get_buf(vq, &len) + && !virtqueue_is_broken(vq)) cpu_relax(); } spin_unlock(&portdev->c_ovq_lock); @@ -647,7 +648,8 @@ static ssize_t __send_to_port(struct port *port, struct scatterlist *sg, * we need to kmalloc a GFP_ATOMIC buffer each time the * console driver writes something out. */ - while (!virtqueue_get_buf(out_vq, &len)) + while (!virtqueue_get_buf(out_vq, &len) + && !virtqueue_is_broken(out_vq)) cpu_relax(); done: spin_unlock_irqrestore(&port->outvq_lock, flags); -- 1.8.3.1