Hey Rusty,
These are the patches to be replaced -- patches 19, 30, 31 from the
previous series. Patch 26 from the earlier series is to be dropped.
The diff to the previous version is:
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index e936026..4218cb9 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -195,9 +195,6 @@ struct port {
/* We should allow only one process to open a port */
bool guest_connected;
-
- /* Does the Host not want to accept more data currently? */
- bool host_throttled;
};
/* This is the very early arch-specified put chars function. */
@@ -414,17 +411,6 @@ static ssize_t send_buf(struct port *port, const char *in_buf, size_t in_count,
out_vq = port->out_vq;
buf = port->outbuf;
- if (buf->len) {
- /*
- * Nonzero buf->len means we had queued a buffer
- * earlier to the Host to be consumed. Get the buffer
- * back for this write request; wait while the Host
- * consumes it.
- */
- while (!out_vq->vq_ops->get_buf(out_vq, &tmplen))
- cpu_relax();
- }
-
if (in_count > buf->size)
in_count = buf->size;
@@ -448,9 +434,21 @@ static ssize_t send_buf(struct port *port, const char *in_buf, size_t in_count,
/* Tell Host to go! */
out_vq->vq_ops->kick(out_vq);
- if (ret < 0)
+ if (ret < 0) {
buf->len = 0;
+ goto fail;
+ }
+ /*
+ * Wait till the host acknowledges it pushed out the data we
+ * sent. Also ensure we return to userspace the number of
+ * bytes that were successfully consumed by the host.
+ */
+ while (!out_vq->vq_ops->get_buf(out_vq, &tmplen))
+ cpu_relax();
+
+ buf->len = tmplen;
+fail:
/* We're expected to return the amount of data we wrote */
return buf->len;
}
@@ -553,9 +551,6 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
port = filp->private_data;
- if (port->host_throttled)
- return -ENOSPC;
-
return send_buf(port, ubuf, count, true);
}
@@ -570,7 +565,7 @@ static unsigned int port_fops_poll(struct file *filp, poll_table *wait)
ret = 0;
if (port->inbuf)
ret |= POLLIN | POLLRDNORM;
- if (port->host_connected && !port->host_throttled)
+ if (port->host_connected)
ret |= POLLOUT;
if (!port->host_connected)
ret |= POLLHUP;
@@ -839,8 +834,6 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
out_offset += snprintf(buf + out_offset, out_count - out_offset,
"host_connected: %d\n", port->host_connected);
out_offset += snprintf(buf + out_offset, out_count - out_offset,
- "host_throttled: %d\n", port->host_throttled);
- out_offset += snprintf(buf + out_offset, out_count - out_offset,
"is_console: %s\n",
is_console_port(port) ? "yes" : "no");
out_offset += snprintf(buf + out_offset, out_count - out_offset,
@@ -961,18 +954,6 @@ static void handle_control_message(struct ports_device *portdev,
err);
break;
- case VIRTIO_CONSOLE_THROTTLE_PORT:
- /*
- * Hosts can govern some policy to disallow rogue
- * guest processes writing indefinitely to ports
- * leading to OOM situations. If we receive this
- * message here, it means the Host side of the port
- * either reached its max. limit to cache data or
- * signal to us that the host is ready to accept more
- * data.
- */
- port->host_throttled = cpkt->value;
- break;
case VIRTIO_CONSOLE_PORT_REMOVE:
/*
* Hot unplug the port. We don't decrement nr_ports
@@ -1130,7 +1111,6 @@ static int add_port(struct ports_device *portdev, u32 id)
port->cons.hvc = NULL;
port->host_connected = port->guest_connected = false;
- port->host_throttled = false;
port->in_vq = portdev->in_vqs[port->id];
port->out_vq = portdev->out_vqs[port->id];
diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h
index 96c5832..dd08675 100644
--- a/include/linux/virtio_console.h
+++ b/include/linux/virtio_console.h
@@ -41,8 +41,7 @@ struct virtio_console_control {
#define VIRTIO_CONSOLE_RESIZE 2
#define VIRTIO_CONSOLE_PORT_OPEN 3
#define VIRTIO_CONSOLE_PORT_NAME 4
-#define VIRTIO_CONSOLE_THROTTLE_PORT 5
-#define VIRTIO_CONSOLE_PORT_REMOVE 6
+#define VIRTIO_CONSOLE_PORT_REMOVE 5
#ifdef __KERNEL__
int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int));
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