aoe: use dynamic number of remote ports for AoE storage target

Many AoE targets have four or fewer network ports, but some existing
storage devices have many, and the AoE protocol sets no limit.

This patch allows the use of more than eight remote MAC addresses per AoE
target, while reducing the amount of memory used by the aoe driver in
cases where there are many AoE targets with fewer than eight MAC addresses
each.

Signed-off-by: Ed Cashin <[e-mail]>
Cc: Jens Axboe <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/block/aoe/aoe.h

···
 enum {
 	DEFAULTBCNT = 2 * 512,	/* 2 sectors */
 	MIN_BUFS = 16,
-	NTARGETS = 8,
+	NTARGETS = 4,
 	NAOEIFS = 8,
 	NSKBPOOLMAX = 256,
 	NFACTIVE = 61,
···
 	ulong maxbcnt;
 	struct list_head factive[NFACTIVE];	/* hash of active frames */
 	struct list_head rexmitq; /* deferred retransmissions */
-	struct aoetgt *targets[NTARGETS];
+	struct aoetgt **targets;
+	ulong ntargets;		/* number of allocated aoetgt pointers */
 	struct aoetgt **tgt;	/* target in use when working */
-	ulong ntargets;
 	ulong kicked;
 	char ident[512];
 };

drivers/block/aoe/aoeblk.c

···
 	nd = nds;
 	ne = nd + ARRAY_SIZE(nds);
 	t = d->targets;
-	te = t + NTARGETS;
+	te = t + d->ntargets;
 	for (; t < te && *t; t++) {
 		ifp = (*t)->ifs;
 		e = ifp + NAOEIFS;

drivers/block/aoe/aoecmd.c

···
 	int use_tainted;
 	int has_untainted;
 
-	if (d->targets[0] == NULL) {	/* shouldn't happen, but I'm paranoid */
+	if (!d->targets || !d->targets[0]) {
 		printk(KERN_ERR "aoe: NULL TARGETS!\n");
 		return NULL;
 	}
 	tt = d->tgt;	/* last used target */
 	for (use_tainted = 0, has_untainted = 0;;) {
 		tt++;
-		if (tt >= &d->targets[NTARGETS] || !*tt)
+		if (tt >= &d->targets[d->ntargets] || !*tt)
 			tt = d->targets;
 		t = *tt;
 		if (!t->taint) {
···
 	struct aoetgt **t, **e;
 
 	t = d->targets;
-	e = t + NTARGETS;
+	e = t + d->ntargets;
 	for (; t < e && *t; t++)
 		if (memcmp((*t)->addr, addr, sizeof((*t)->addr)) == 0)
 			return *t;
···
 	return skb;
 }
 
+static struct aoetgt **
+grow_targets(struct aoedev *d)
+{
+	ulong oldn, newn;
+	struct aoetgt **tt;
+
+	oldn = d->ntargets;
+	newn = oldn * 2;
+	tt = kcalloc(newn, sizeof(*d->targets), GFP_ATOMIC);
+	if (!tt)
+		return NULL;
+	memmove(tt, d->targets, sizeof(*d->targets) * oldn);
+	d->tgt = tt + (d->tgt - d->targets);
+	kfree(d->targets);
+	d->targets = tt;
+	d->ntargets = newn;
+
+	return &d->targets[oldn];
+}
+
 static struct aoetgt *
 addtgt(struct aoedev *d, char *addr, ulong nframes)
 {
 	struct aoetgt *t, **tt, **te;
 
 	tt = d->targets;
-	te = tt + NTARGETS;
+	te = tt + d->ntargets;
 	for (; tt < te && *tt; tt++)
 		;
 
 	if (tt == te) {
-		printk(KERN_INFO
-			"aoe: device addtgt failure; too many targets\n");
-		return NULL;
+		tt = grow_targets(d);
+		if (!tt)
+			goto nomem;
 	}
 	t = kzalloc(sizeof(*t), GFP_ATOMIC);
-	if (!t) {
-		printk(KERN_INFO "aoe: cannot allocate memory to add target\n");
-		return NULL;
-	}
-
-	d->ntargets++;
+	if (!t)
+		goto nomem;
 	t->nframes = nframes;
 	t->d = d;
 	memcpy(t->addr, addr, sizeof t->addr);
···
 	t->maxout = t->nframes / 2;
 	INIT_LIST_HEAD(&t->ffree);
 	return *tt = t;
+
+ nomem:
+	pr_info("aoe: cannot allocate memory to add target\n");
+	return NULL;
 }
 
 static void
···
 	int bcnt = 0;
 
 	t = d->targets;
-	e = t + NTARGETS;
+	e = t + d->ntargets;
 	for (; t < e && *t; t++)
 		if (bcnt == 0 || bcnt > (*t)->minbcnt)
 			bcnt = (*t)->minbcnt;
···
 	d->maxbcnt = 0;
 
 	t = d->targets;
-	te = t + NTARGETS;
+	te = t + d->ntargets;
 	for (; t < te && *t; t++)
 		aoecmd_wreset(*t);
 }

drivers/block/aoe/aoedev.c

···
 
 	/* reset window dressings */
 	tt = d->targets;
-	te = tt + NTARGETS;
+	te = tt + d->ntargets;
 	for (; tt < te && (t = *tt); tt++) {
 		aoecmd_wreset(t);
 		t->nout = 0;
···
 		blk_cleanup_queue(d->blkq);
 	}
 	t = d->targets;
-	e = t + NTARGETS;
+	e = t + d->ntargets;
 	for (; t < e && *t; t++)
 		freetgt(d, *t);
 	if (d->bufpool)
···
 			dd = &d->next;
 		}
 		spin_unlock(&d->lock);
+		if (doomed)
+			kfree(doomed->targets);
 		kfree(doomed);
 	}
 	spin_unlock_irqrestore(&devlist_lock, flags);
···
 	d = kcalloc(1, sizeof *d, GFP_ATOMIC);
 	if (!d)
 		goto out;
+	d->targets = kcalloc(NTARGETS, sizeof(*d->targets), GFP_ATOMIC);
+	if (!d->targets) {
+		kfree(d);
+		goto out;
+	}
+	d->ntargets = NTARGETS;
 	INIT_WORK(&d->work, aoecmd_sleepwork);
 	spin_lock_init(&d->lock);
 	skb_queue_head_init(&d->skbpool);