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authorAmit Shah <amit.shah@redhat.com>2010-01-18 19:15:01 +0530
committerRusty Russell <rusty@rustcorp.com.au>2010-02-24 14:22:36 +1030
commitfdb9a054554e1e435e927c9a47a999f026abd408 (patch)
tree4ef632d26bf6068de7ab14f99547fd94e0c939b6
parent21206ede8826fd9d2eb72e05b429f3ccb1bdaff5 (diff)
virtio: console: encapsulate buffer information in a struct
Collect port buffer, used_len, offset fields into a single structure. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--drivers/char/virtio_console.c70
1 files changed, 55 insertions, 15 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 9ea9223c5c5..699fc98ec8d 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -21,12 +21,24 @@
#include <linux/virtio_console.h>
#include "hvc_console.h"
+struct port_buffer {
+ char *buf;
+
+ /* size of the buffer in *buf above */
+ size_t size;
+
+ /* used length of the buffer */
+ size_t len;
+ /* offset in the buf from which to consume data */
+ size_t offset;
+};
+
struct port {
struct virtqueue *in_vq, *out_vq;
struct virtio_device *vdev;
- /* This is our input buffer, and how much data is left in it. */
- char *inbuf;
- unsigned int used_len, offset;
+
+ /* The current buffer from which data has to be fed to readers */
+ struct port_buffer *inbuf;
/* The hvc device */
struct hvc_struct *hvc;
@@ -38,6 +50,33 @@ static struct port console;
/* This is the very early arch-specified put chars function. */
static int (*early_put_chars)(u32, const char *, int);
+static void free_buf(struct port_buffer *buf)
+{
+ kfree(buf->buf);
+ kfree(buf);
+}
+
+static struct port_buffer *alloc_buf(size_t buf_size)
+{
+ struct port_buffer *buf;
+
+ buf = kmalloc(sizeof(*buf), GFP_KERNEL);
+ if (!buf)
+ goto fail;
+ buf->buf = kzalloc(buf_size, GFP_KERNEL);
+ if (!buf->buf)
+ goto free_buf;
+ buf->len = 0;
+ buf->offset = 0;
+ buf->size = buf_size;
+ return buf;
+
+free_buf:
+ kfree(buf);
+fail:
+ return NULL;
+}
+
/*
* The put_chars() callback is pretty straightforward.
*
@@ -79,7 +118,7 @@ static int put_chars(u32 vtermno, const char *buf, int count)
static void add_inbuf(struct port *port)
{
struct scatterlist sg[1];
- sg_init_one(sg, port->inbuf, PAGE_SIZE);
+ sg_init_one(sg, port->inbuf->buf, PAGE_SIZE);
/* Should always be able to add one buffer to an empty queue. */
if (port->in_vq->vq_ops->add_buf(port->in_vq, sg, 0, 1, port) < 0)
@@ -98,6 +137,7 @@ static void add_inbuf(struct port *port)
static int get_chars(u32 vtermno, char *buf, int count)
{
struct port *port;
+ unsigned int len;
port = &console;
@@ -105,22 +145,23 @@ static int get_chars(u32 vtermno, char *buf, int count)
BUG_ON(!port->in_vq);
/* No more in buffer? See if they've (re)used it. */
- if (port->offset == port->used_len) {
- if (!port->in_vq->vq_ops->get_buf(port->in_vq, &port->used_len))
+ if (port->inbuf->offset == port->inbuf->len) {
+ if (!port->in_vq->vq_ops->get_buf(port->in_vq, &len))
return 0;
- port->offset = 0;
+ port->inbuf->offset = 0;
+ port->inbuf->len = len;
}
/* You want more than we have to give? Well, try wanting less! */
- if (port->offset + count > port->used_len)
- count = port->used_len - port->offset;
+ if (port->inbuf->offset + count > port->inbuf->len)
+ count = port->inbuf->len - port->inbuf->offset;
/* Copy across to their buffer and increment offset. */
- memcpy(buf, port->inbuf + port->offset, count);
- port->offset += count;
+ memcpy(buf, port->inbuf->buf + port->inbuf->offset, count);
+ port->inbuf->offset += count;
/* Finished? Re-register buffer so Host will use it again. */
- if (port->offset == port->used_len)
+ if (port->inbuf->offset == port->inbuf->len)
add_inbuf(port);
return count;
@@ -220,8 +261,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
port->vdev = vdev;
/* This is the scratch page we use to receive console input */
- port->used_len = 0;
- port->inbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ port->inbuf = alloc_buf(PAGE_SIZE);
if (!port->inbuf) {
err = -ENOMEM;
goto fail;
@@ -263,7 +303,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
free_vqs:
vdev->config->del_vqs(vdev);
free:
- kfree(port->inbuf);
+ free_buf(port->inbuf);
fail:
return err;
}