On (Mon) Feb 01 2010 [10:49:51], Rusty Russell wrote:
> On Sat, 30 Jan 2010 12:12:40 am Amit Shah wrote:
> > When ports get advertised as char devices, the buffers will come from
> > userspace. Equip the fill_readbuf function with the ability to write
> > to userspace buffers.
> >
> > Signed-off-by: Amit Shah <amit.shah@xxxxxxxxxx>
> > ---
> > drivers/char/virtio_console.c | 20 ++++++++++++++------
> > 1 files changed, 14 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> > index 9d33239..5f61021 100644
> > --- a/drivers/char/virtio_console.c
> > +++ b/drivers/char/virtio_console.c
> > @@ -365,7 +365,8 @@ fail:
> > * Give out the data that's requested from the buffer that we have
> > * queued up.
> > */
> > -static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count)
> > +static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count,
> > + bool to_user)
>
> This patch does not apply: your previous 19/31 "Introduce a send_buf function
> for a common path for sending data to host" made this "void *out_buf". The
> rest I can't even sort out.
Sorry for that, Rusty.
I've sent you a tarball privately.
The tarball contains an additional patch (contained in the series
itself), that drops the use of outbuf for sending control messages
as well:
(The 'outbuf' was used earlier when we had multiple buffers that could
be queued up for the host to consume. We now only queue up one buffer at
a time and wait for the host to ack the buffer before we move along.
When we revisit the design to allow multiple out-buffers, we can go this
path again.)
drivers/char/virtio_console.c | 21 ++++-----------------
1 files changed, 4 insertions(+), 17 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 2c2de35..793285d 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -134,9 +134,6 @@ struct ports_device {
/* Array of per-port IO virtqueues */
struct virtqueue **in_vqs, **out_vqs;
- /* The control messages to the Host are sent via this buffer */
- struct port_buffer *outbuf;
-
/* Used for numbering devices for sysfs and debugfs */
unsigned int drv_index;
@@ -372,8 +369,7 @@ static ssize_t send_control_msg(struct port *port, unsigned int event,
struct scatterlist sg[1];
struct virtio_console_control cpkt;
struct virtqueue *vq;
- struct port_buffer *outbuf;
- int tmplen;
+ int len;
if (!use_multiport(port->portdev))
return 0;
@@ -383,14 +379,11 @@ static ssize_t send_control_msg(struct port *port, unsigned int event,
cpkt.value = value;
vq = port->portdev->c_ovq;
- outbuf = port->portdev->outbuf;
-
- memcpy(outbuf->buf, (void *)&cpkt, sizeof(cpkt));
- sg_init_one(sg, outbuf->buf, sizeof(cpkt));
- if (vq->vq_ops->add_buf(vq, sg, 1, 0, outbuf) >= 0) {
+ sg_init_one(sg, &cpkt, sizeof(cpkt));
+ if (vq->vq_ops->add_buf(vq, sg, 1, 0, &cpkt) >= 0) {
vq->vq_ops->kick(vq);
- while (!vq->vq_ops->get_buf(vq, &tmplen))
+ while (!vq->vq_ops->get_buf(vq, &len))
cpu_relax();
}
return 0;
@@ -1432,12 +1425,6 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
INIT_WORK(&portdev->control_work, &control_work_handler);
INIT_WORK(&portdev->config_work, &config_work_handler);
- portdev->outbuf = alloc_buf(PAGE_SIZE);
- if (!portdev->outbuf) {
- err = -ENOMEM;
- dev_err(&vdev->dev, "OOM for control outbuf\n");
- goto free_vqs;
- }
fill_queue(portdev->c_ivq, &portdev->cvq_lock);
}
Amit
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