X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=net%2F9p%2Ftrans_virtio.c;h=afde1a89fbb328d1dbda695c6824e205c7997e1a;hb=d6a8536a93a3d14b6e5e3e3a59b9fb2bca6e8df2;hp=cb50f4ae5eefa1f5cde720f43daaf6f19e9034eb;hpb=eca281aad0c293e7698edea5834c252dd8108afa;p=~andy%2Flinux 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);