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Diffstat (limited to 'net/9p/trans_virtio.c')
-rw-r--r--net/9p/trans_virtio.c142
1 files changed, 91 insertions, 51 deletions
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index cb50f4ae5ee..afde1a89fbb 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -49,8 +49,6 @@
/* a single mutex to manage channel initialization and attachment */
static DEFINE_MUTEX(virtio_9p_lock);
-/* global which tracks highest initialized channel */
-static int chan_index;
/**
* struct virtio_chan - per-instance transport information
@@ -68,8 +66,7 @@ static int chan_index;
*
*/
-static struct virtio_chan {
- bool initialized;
+struct virtio_chan {
bool inuse;
spinlock_t lock;
@@ -80,7 +77,17 @@ static struct virtio_chan {
/* Scatterlist: can be too big for stack. */
struct scatterlist sg[VIRTQUEUE_NUM];
-} channels[MAX_9P_CHAN];
+
+ int tag_len;
+ /*
+ * tag name to identify a mount Non-null terminated
+ */
+ char *tag;
+
+ struct list_head chan_list;
+};
+
+static struct list_head virtio_chan_list;
/* How many bytes left in this page. */
static unsigned int rest_of_page(void *data)
@@ -213,30 +220,38 @@ p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
return 0;
}
+static ssize_t p9_mount_tag_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct virtio_chan *chan;
+ struct virtio_device *vdev;
+
+ vdev = dev_to_virtio(dev);
+ chan = vdev->priv;
+
+ return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
+}
+
+static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
+
/**
* p9_virtio_probe - probe for existence of 9P virtio channels
* @vdev: virtio device to probe
*
- * This probes for existing virtio channels. At present only
- * a single channel is in use, so in the future more work may need
- * to be done here.
+ * This probes for existing virtio channels.
*
*/
static int p9_virtio_probe(struct virtio_device *vdev)
{
+ __u16 tag_len;
+ char *tag;
int err;
struct virtio_chan *chan;
- int index;
- mutex_lock(&virtio_9p_lock);
- index = chan_index++;
- chan = &channels[index];
- mutex_unlock(&virtio_9p_lock);
-
- if (chan_index > MAX_9P_CHAN) {
- printk(KERN_ERR "9p: virtio: Maximum channels exceeded\n");
- BUG();
+ chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
+ if (!chan) {
+ printk(KERN_ERR "9p: Failed to allocate virtio 9P channel\n");
err = -ENOMEM;
goto fail;
}
@@ -255,15 +270,37 @@ static int p9_virtio_probe(struct virtio_device *vdev)
sg_init_table(chan->sg, VIRTQUEUE_NUM);
chan->inuse = false;
- chan->initialized = true;
+ if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
+ vdev->config->get(vdev,
+ offsetof(struct virtio_9p_config, tag_len),
+ &tag_len, sizeof(tag_len));
+ } else {
+ err = -EINVAL;
+ goto out_free_vq;
+ }
+ tag = kmalloc(tag_len, GFP_KERNEL);
+ if (!tag) {
+ err = -ENOMEM;
+ goto out_free_vq;
+ }
+ vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag),
+ tag, tag_len);
+ chan->tag = tag;
+ chan->tag_len = tag_len;
+ err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
+ if (err) {
+ kfree(tag);
+ goto out_free_vq;
+ }
+ mutex_lock(&virtio_9p_lock);
+ list_add_tail(&chan->chan_list, &virtio_chan_list);
+ mutex_unlock(&virtio_9p_lock);
return 0;
out_free_vq:
vdev->config->del_vqs(vdev);
+ kfree(chan);
fail:
- mutex_lock(&virtio_9p_lock);
- chan_index--;
- mutex_unlock(&virtio_9p_lock);
return err;
}
@@ -280,35 +317,31 @@ fail:
* We use a simple reference count mechanism to ensure that only a single
* mount has a channel open at a time.
*
- * Bugs: doesn't allow identification of a specific channel
- * to allocate, channels are allocated sequentially. This was
- * a pragmatic decision to get things rolling, but ideally some
- * way of identifying the channel to attach to would be nice
- * if we are going to support multiple channels.
- *
*/
static int
p9_virtio_create(struct p9_client *client, const char *devname, char *args)
{
- struct virtio_chan *chan = channels;
- int index = 0;
+ struct virtio_chan *chan;
+ int ret = -ENOENT;
+ int found = 0;
mutex_lock(&virtio_9p_lock);
- while (index < MAX_9P_CHAN) {
- if (chan->initialized && !chan->inuse) {
- chan->inuse = true;
- break;
- } else {
- index++;
- chan = &channels[index];
+ list_for_each_entry(chan, &virtio_chan_list, chan_list) {
+ if (!strncmp(devname, chan->tag, chan->tag_len)) {
+ if (!chan->inuse) {
+ chan->inuse = true;
+ found = 1;
+ break;
+ }
+ ret = -EBUSY;
}
}
mutex_unlock(&virtio_9p_lock);
- if (index >= MAX_9P_CHAN) {
+ if (!found) {
printk(KERN_ERR "9p: no channels available\n");
- return -ENODEV;
+ return ret;
}
client->trans = (void *)chan;
@@ -329,11 +362,15 @@ static void p9_virtio_remove(struct virtio_device *vdev)
struct virtio_chan *chan = vdev->priv;
BUG_ON(chan->inuse);
+ vdev->config->del_vqs(vdev);
+
+ mutex_lock(&virtio_9p_lock);
+ list_del(&chan->chan_list);
+ mutex_unlock(&virtio_9p_lock);
+ sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
+ kfree(chan->tag);
+ kfree(chan);
- if (chan->initialized) {
- vdev->config->del_vqs(vdev);
- chan->initialized = false;
- }
}
static struct virtio_device_id id_table[] = {
@@ -341,13 +378,19 @@ static struct virtio_device_id id_table[] = {
{ 0 },
};
+static unsigned int features[] = {
+ VIRTIO_9P_MOUNT_TAG,
+};
+
/* The standard "struct lguest_driver": */
static struct virtio_driver p9_virtio_drv = {
- .driver.name = KBUILD_MODNAME,
- .driver.owner = THIS_MODULE,
- .id_table = id_table,
- .probe = p9_virtio_probe,
- .remove = p9_virtio_remove,
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = p9_virtio_probe,
+ .remove = p9_virtio_remove,
};
static struct p9_trans_module p9_virtio_trans = {
@@ -364,10 +407,7 @@ static struct p9_trans_module p9_virtio_trans = {
/* The standard init function */
static int __init p9_virtio_init(void)
{
- int count;
-
- for (count = 0; count < MAX_9P_CHAN; count++)
- channels[count].initialized = false;
+ INIT_LIST_HEAD(&virtio_chan_list);
v9fs_register_trans(&p9_virtio_trans);
return register_virtio_driver(&p9_virtio_drv);