+static int
+revalidate(const char __user *str, size_t size)
+{
+ int major, minor, n;
+ ulong flags;
+ struct aoedev *d;
+ char buf[16];
+
+ if (size >= sizeof buf)
+ return -EINVAL;
+ buf[sizeof buf - 1] = '\0';
+ if (copy_from_user(buf, str, size))
+ return -EFAULT;
+
+ /* should be e%d.%d format */
+ n = sscanf(buf, "e%d.%d", &major, &minor);
+ if (n != 2) {
+ printk(KERN_ERR "aoe: invalid device specification\n");
+ return -EINVAL;
+ }
+ d = aoedev_by_aoeaddr(major, minor);
+ if (!d)
+ return -EINVAL;
+
+ spin_lock_irqsave(&d->lock, flags);
+ d->flags &= ~DEVFL_MAXBCNT;
+ d->flags |= DEVFL_PAUSE;
+ spin_unlock_irqrestore(&d->lock, flags);
+ aoecmd_cfg(major, minor);
+
+ return 0;
+}
+