[PATCH] aoe [2/8]: support dynamic resizing of AoE devices

Allow the driver to recognize AoE devices that have changed size.
Devices not in use are updated automatically, and devices that are in
use are updated at user request.

Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/block/aoe/aoechr.c b/drivers/block/aoe/aoechr.c
index 41ae0ed..5327f55 100644
--- a/drivers/block/aoe/aoechr.c
+++ b/drivers/block/aoe/aoechr.c
@@ -13,6 +13,7 @@
 	MINOR_ERR = 2,
 	MINOR_DISCOVER,
 	MINOR_INTERFACES,
+	MINOR_REVALIDATE,
 	MSGSZ = 2048,
 	NARGS = 10,
 	NMSG = 100,		/* message backlog to retain */
@@ -41,6 +42,7 @@
 	{ MINOR_ERR, "err" },
 	{ MINOR_DISCOVER, "discover" },
 	{ MINOR_INTERFACES, "interfaces" },
+	{ MINOR_REVALIDATE, "revalidate" },
 };
 
 static int
@@ -62,6 +64,39 @@
 	return 0;
 }
 
+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: %s: invalid device specification\n",
+			__FUNCTION__);
+		return -EINVAL;
+	}
+	d = aoedev_by_aoeaddr(major, minor);
+	if (!d)
+		return -EINVAL;
+
+	spin_lock_irqsave(&d->lock, flags);
+	d->flags |= DEVFL_PAUSE;
+	spin_unlock_irqrestore(&d->lock, flags);
+	aoecmd_cfg(major, minor);
+
+	return 0;
+}
+
 void
 aoechr_error(char *msg)
 {
@@ -114,6 +149,8 @@
 	case MINOR_INTERFACES:
 		ret = interfaces(buf, cnt);
 		break;
+	case MINOR_REVALIDATE:
+		ret = revalidate(buf, cnt);
 	}
 	if (ret == 0)
 		ret = cnt;