diff options
Diffstat (limited to 'drivers/char/virtio_console.c')
-rw-r--r-- | drivers/char/virtio_console.c | 70 |
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; } |