Patchwork [3/3] virtio-serial-bus: let chardev know the exact number of bytes requested

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Submitter Amit Shah
Date July 6, 2012, 10:37 a.m.
Message ID <ee2f577604f4b423c5e85b823099d149326e08f5.1341569262.git.amit.shah@redhat.com>
Download mbox | patch
Permalink /patch/169408/
State New
Headers show

Comments

Amit Shah - July 6, 2012, 10:37 a.m.
Using the virtqueue_avail_bytes() function had an unnecessarily
crippling effect on the number of bytes needed by the guest as reported
to the chardev layer in the can_read() callback.

Using the new virtqueue_get_avail_bytes() function will let us advertise
the exact number of bytes we can send to the guest.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/virtio-serial-bus.c |   11 +++--------
 1 files changed, 3 insertions(+), 8 deletions(-)

Patch

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index 96382a4..44d5862 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -287,6 +287,7 @@  ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,
 size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
 {
     VirtQueue *vq = port->ivq;
+    unsigned int bytes;
 
     if (!virtio_queue_ready(vq) ||
         !(port->vser->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK) ||
@@ -296,14 +297,8 @@  size_t virtio_serial_guest_ready(VirtIOSerialPort *port)
     if (use_multiport(port->vser) && !port->guest_connected) {
         return 0;
     }
-
-    if (virtqueue_avail_bytes(vq, 4096, 0)) {
-        return 4096;
-    }
-    if (virtqueue_avail_bytes(vq, 1, 0)) {
-        return 1;
-    }
-    return 0;
+    virtqueue_get_avail_bytes(vq, &bytes, NULL);
+    return bytes;
 }
 
 static void flush_queued_data_bh(void *opaque)