virtio/console: Wait until the port is ready on splice

Wait if the port is not connected or full on splice
like as write is doing.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 27 insertions, 12 deletions

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 22b737353017..b2fc2abedc79 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -724,6 +724,26 @@ static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
         return fill_readbuf(port, ubuf, count, true);
 }
 
+static int wait_port_writable(struct port *port, bool nonblock)
+{
+        int ret;
+
+        if (will_write_block(port)) {
+                if (nonblock)
+                        return -EAGAIN;
+
+                ret = wait_event_freezable(port->waitqueue,
+                                           !will_write_block(port));
+                if (ret < 0)
+                        return ret;
+        }
+        /* Port got hot-unplugged. */
+        if (!port->guest_connected)
+                return -ENODEV;
+
+        return 0;
+}
+
 static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
                                size_t count, loff_t *offp)
 {
@@ -740,18 +760,9 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
 
         nonblock = filp->f_flags & O_NONBLOCK;
 
-        if (will_write_block(port)) {
-                if (nonblock)
-                        return -EAGAIN;
-
-                ret = wait_event_freezable(port->waitqueue,
-                                           !will_write_block(port));
-                if (ret < 0)
-                        return ret;
-        }
-        /* Port got hot-unplugged. */
-        if (!port->guest_connected)
-                return -ENODEV;
+        ret = wait_port_writable(port, nonblock);
+        if (ret < 0)
+                return ret;
 
         count = min((size_t)(32 * 1024), count);
 
@@ -851,6 +862,10 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
                 .u.data = &sgl,
         };
 
+        ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
+        if (ret < 0)
+                return ret;
+
         sgl.n = 0;
         sgl.len = 0;
         sgl.sg = kmalloc(sizeof(struct scatterlist) * MAX_SPLICE_PAGES,