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authorAmit Shah <amit.shah@redhat.com>2009-12-21 17:28:51 +0530
committerRusty Russell <rusty@rustcorp.com.au>2010-02-24 14:22:51 +1030
commitf997f00bf8c3ddf748d757105afa1a7dd5297208 (patch)
treeaedb212484ca3ff86ec5eb9c141a70e64df96f59 /drivers/char
parent203baab8ba3195dd929473ba95b91c2b838833e6 (diff)
downloadlinux-f997f00bf8c3ddf748d757105afa1a7dd5297208.tar.bz2
virtio: console: Introduce a send_buf function for a common path for sending data to host
Adding support for generic ports that will write to userspace will need some code changes. Consolidate the write routine into send_buf() and put_chars() now just calls into the new function. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/virtio_console.c50
1 files changed, 33 insertions, 17 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 5096d92f5b89..d01051060be3 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -233,6 +233,38 @@ static bool port_has_data(struct port *port)
return ret;
}
+static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count)
+{
+ struct scatterlist sg[1];
+ struct virtqueue *out_vq;
+ ssize_t ret;
+ unsigned int len;
+
+ out_vq = port->out_vq;
+
+ sg_init_one(sg, in_buf, in_count);
+ ret = out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, in_buf);
+
+ /* Tell Host to go! */
+ out_vq->vq_ops->kick(out_vq);
+
+ if (ret < 0) {
+ 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, &len))
+ cpu_relax();
+fail:
+ /* We're expected to return the amount of data we wrote */
+ return len;
+}
+
/*
* Give out the data that's requested from the buffer that we have
* queued up.
@@ -280,10 +312,7 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count)
*/
static int put_chars(u32 vtermno, const char *buf, int count)
{
- struct scatterlist sg[1];
struct port *port;
- struct virtqueue *out_vq;
- unsigned int len;
port = find_port_by_vtermno(vtermno);
if (!port)
@@ -292,20 +321,7 @@ static int put_chars(u32 vtermno, const char *buf, int count)
if (unlikely(early_put_chars))
return early_put_chars(vtermno, buf, count);
- out_vq = port->out_vq;
- /* This is a convenient routine to initialize a single-elem sg list */
- sg_init_one(sg, buf, count);
-
- /* This shouldn't fail: if it does, we lose chars. */
- if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, port) >= 0) {
- /* Tell Host to go! */
- out_vq->vq_ops->kick(out_vq);
- while (!out_vq->vq_ops->get_buf(out_vq, &len))
- cpu_relax();
- }
-
- /* We're expected to return the amount of data we wrote: all of it. */
- return count;
+ return send_buf(port, (void *)buf, count);
}
/*