nbd: prevent IDR lookups from finding partially initialized devices

[linux-2.6-microblaze.git] / drivers / block / nbd.c

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 938ca7f..b1ed236 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1747,7 +1747,11 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
 
        mutex_init(&nbd->config_lock);
        refcount_set(&nbd->config_refs, 0);
-       refcount_set(&nbd->refs, refs);
+       /*
+        * Start out with a zero references to keep other threads from using
+        * this device until it is fully initialized.
+        */
+       refcount_set(&nbd->refs, 0);
        INIT_LIST_HEAD(&nbd->list);
        disk->major = NBD_MAJOR;
 
@@ -1766,6 +1770,11 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
        disk->private_data = nbd;
        sprintf(disk->disk_name, "nbd%d", index);
        add_disk(disk);
+
+       /*
+        * Now publish the device.
+        */
+       refcount_set(&nbd->refs, refs);
        nbd_total_devices++;
        return nbd;