net/9p: Use the tag name in the config space for identifying mount point
This patch use the tag name in the config space to identify the
mount device. The the virtio device name depend on the enumeration
order of the device and may not remain the same across multiple boots
So we use the tag name which is set via qemu option to uniquely identify
the mount device
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 0aaed48..026775a 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -78,6 +78,12 @@
/* Scatterlist: can be too big for stack. */
struct scatterlist sg[VIRTQUEUE_NUM];
+ int tag_len;
+ /*
+ * tag name to identify a mount Non-null terminated
+ */
+ char *tag;
+
struct list_head chan_list;
};
@@ -224,6 +230,8 @@
static int p9_virtio_probe(struct virtio_device *vdev)
{
+ __u16 tag_len;
+ char *tag;
int err;
struct virtio_chan *chan;
@@ -248,6 +256,23 @@
sg_init_table(chan->sg, VIRTQUEUE_NUM);
chan->inuse = false;
+ 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;
mutex_lock(&virtio_9p_lock);
list_add_tail(&chan->chan_list, &virtio_chan_list);
mutex_unlock(&virtio_9p_lock);
@@ -284,7 +309,7 @@
mutex_lock(&virtio_9p_lock);
list_for_each_entry(chan, &virtio_chan_list, chan_list) {
- if (!strcmp(devname, dev_name(&chan->vdev->dev))) {
+ if (!strncmp(devname, chan->tag, chan->tag_len)) {
if (!chan->inuse) {
chan->inuse = true;
found = 1;
@@ -323,6 +348,7 @@
mutex_lock(&virtio_9p_lock);
list_del(&chan->chan_list);
mutex_unlock(&virtio_9p_lock);
+ kfree(chan->tag);
kfree(chan);
}
@@ -332,13 +358,19 @@
{ 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 = {
