[V9fs-developer,2/2] net/9p: Support variable size mount_tag names

Commit Message

Aneesh Kumar K.V Feb. 19, 2010, 5:45 a.m. UTC

None

Patch

diff --git a/include/linux/virtio_9p.h b/include/linux/virtio_9p.h
index 46ed18f..e7fb078 100644
--- a/include/linux/virtio_9p.h
+++ b/include/linux/virtio_9p.h
@@ -4,11 +4,12 @@ 
  * compatible drivers/servers. */
 #include <linux/virtio_ids.h>
 #include <linux/virtio_config.h>
-#define MAX_TAG_LEN 8
 
 struct virtio_9p_config {
-	/* tag name for the mount point */
-	__u8 tag[MAX_TAG_LEN];
+	/* length of the tag name */
+	__u16 tag_len;
+	/* non-NULL terminated tag name */
+	__u8 tag[0];
 } __attribute__((packed));
 
 #endif /* _LINUX_VIRTIO_9P_H */
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 7ae27d2..a04a7e4 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -78,8 +78,11 @@  struct virtio_chan {
 	/* Scatterlist: can be too big for stack. */
 	struct scatterlist sg[VIRTQUEUE_NUM];
 
-	/* tag name to identify a mount */
-	__u8 tag[MAX_TAG_LEN];
+	int tag_len;
+	/*
+	 * tag name to identify a mount Non-null terminated
+	 */
+	char *tag;
 
 	struct list_head chan_list;
 };
@@ -227,7 +230,8 @@  p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
 
 static int p9_virtio_probe(struct virtio_device *vdev)
 {
-	__u8 tag[MAX_TAG_LEN];
+	__u16 tag_len;
+	char *tag;
 	int err;
 	struct virtio_chan *chan;
 
@@ -252,9 +256,17 @@  static int p9_virtio_probe(struct virtio_device *vdev)
 	sg_init_table(chan->sg, VIRTQUEUE_NUM);
 
 	chan->inuse = false;
+	vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag_len),
+			&tag_len, sizeof(tag_len));
+	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, sizeof(tag));
-	memcpy(chan->tag, tag, MAX_TAG_LEN);
+			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);
@@ -291,7 +303,7 @@  p9_virtio_create(struct p9_client *client, const char *devname, char *args)
 
 	mutex_lock(&virtio_9p_lock);
 	list_for_each_entry(chan, &virtio_chan_list, chan_list) {
-		if (!strncmp(devname, chan->tag, MAX_TAG_LEN)) {
+		if (!strncmp(devname, chan->tag, chan->tag_len)) {
 			if (!chan->inuse) {
 				chan->inuse = true;
 				found = 1;
@@ -330,6 +342,7 @@  static void p9_virtio_remove(struct virtio_device *vdev)
 	mutex_lock(&virtio_9p_lock);
 	list_del(&chan->chan_list);
 	mutex_unlock(&virtio_9p_lock);
+	kfree(chan->tag);
 	kfree(chan);
 
 }