aoe: update and specify AoE address guards and error messages

In general, specific is better when it comes to messages about AoE usage
problems.  Also, explicit checks for the AoE broadcast addresses are
added.

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/block/aoe/aoe.h

@@ -49,8 +49,6 @@ struct aoe_hdr {
 	__be32 tag;
 };
 
-#define AOE_MAXSHELF (0xffff-1)	/* one less than the broadcast shelf address */
-
 struct aoe_atahdr {
 	unsigned char aflags;
 	unsigned char errfeat;

drivers/block/aoe/aoecmd.c

@@ -1349,15 +1349,14 @@ aoecmd_cfg_rsp(struct sk_buff *skb)
 			"Check shelf dip switches.\n");
 		return;
 	}
-	if (aoemajor > AOE_MAXSHELF) {
-		pr_info("aoe: e%ld.%d: shelf number too large\n",
+	if (aoemajor == 0xffff) {
+		pr_info("aoe: e%ld.%d: broadcast shelf number invalid\n",
 			aoemajor, (int) h->minor);
 		return;
 	}
-
-	d = aoedev_by_aoeaddr(aoemajor, h->minor, 1);
-	if (d == NULL) {
-		pr_info("aoe: device allocation failure\n");
+	if (h->minor == 0xff) {
+		pr_info("aoe: e%ld.%d: broadcast slot number invalid\n",
+			aoemajor, (int) h->minor);
 		return;
 	}
 
@@ -1365,6 +1364,12 @@ aoecmd_cfg_rsp(struct sk_buff *skb)
 	if (n > aoe_maxout)	/* keep it reasonable */
 		n = aoe_maxout;
 
+	d = aoedev_by_aoeaddr(aoemajor, h->minor, 1);
+	if (d == NULL) {
+		pr_info("aoe: device allocation failure\n");
+		return;
+	}
+
 	spin_lock_irqsave(&d->lock, flags);
 
 	t = gettgt(d, h->src);