If the host port is not open, a write() should either just return if the
file is opened in non-blocking mode, or block till the host port is
opened.
This is just half of the blocking/non-blocking story.
The other half will be addressed when we get rid of the cpu_relax() in
send_buf(). Add a fixme mentioning that case.
Signed-off-by: Amit Shah <amit.shah@xxxxxxxxxx>
---
drivers/char/virtio_console.c | 18 ++++++++++++++++++
1 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index f33ceaa..fa616aa 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -536,6 +536,24 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
port = filp->private_data;
+ if (!port->host_connected) {
+ /*
+ * FIXME: Also check if the vq has enough room to send
+ * this buffer out to the guest. Return EAGAIN or
+ * block in case there's no room. Currently the vq
+ * always has room because we only use one buffer (and
+ * cpu_relax()), but when send_buf() becomes
+ * non-spinning, we'll use more buffers.
+ */
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(port->waitqueue,
+ port->host_connected);
+ if (ret < 0)
+ return ret;
+ }
+
count = min((size_t)(32 * 1024), count);
buf = kmalloc(count, GFP_KERNEL);
--
1.6.2.5
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