aoe: remove vestigial request queue allocation

Before the aoe driver was an I/O request handler, it was a
make_request-style block driver.  Even so, there was a problem where
sysfs expected a request queue to exist, so one was provided in commit
7135a71b ("aoe: allocate unused request_queue for sysfs").

During the transition to the request-handler style, a patch was merged
that was based on a driver without the noop queue, and the noop queue
remained in place after the patch was merged, even though a new
functional queue was introduced by the patch, allocated through
blk_init_queue.

The user impact is a memory leak proportional to the number of AoE
targets discovered.  This patch removes the memory leak and cleans up
vestiges of the old do-nothing queue from the aoeblk_gdalloc function.
Signed-off-by: NEd Cashin <ecashin@coraid.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/block/aoe/aoeblk.c

@@ -278,18 +278,12 @@ aoeblk_gdalloc(void *vp)
 	if (q == NULL) {
 		pr_err("aoe: cannot allocate block queue for %ld.%d\n",
 			d->aoemajor, d->aoeminor);
-		mempool_destroy(mp);
-		goto err_disk;
+		goto err_mempool;
 	}
 
-	d->blkq = blk_alloc_queue(GFP_KERNEL);
-	if (!d->blkq)
-		goto err_mempool;
-	d->blkq->backing_dev_info.name = "aoe";
-	if (bdi_init(&d->blkq->backing_dev_info))
-		goto err_blkq;
 	spin_lock_irqsave(&d->lock, flags);
-	blk_queue_max_hw_sectors(d->blkq, BLK_DEF_MAX_SECTORS);
+	blk_queue_max_hw_sectors(q, BLK_DEF_MAX_SECTORS);
+	q->backing_dev_info.name = "aoe";
 	q->backing_dev_info.ra_pages = READ_AHEAD / PAGE_CACHE_SIZE;
 	d->bufpool = mp;
 	d->blkq = gd->queue = q;
@@ -314,11 +308,8 @@ aoeblk_gdalloc(void *vp)
 	aoedisk_add_sysfs(d);
 	return;
 
-err_blkq:
-	blk_cleanup_queue(d->blkq);
-	d->blkq = NULL;
 err_mempool:
-	mempool_destroy(d->bufpool);
+	mempool_destroy(mp);
 err_disk:
 	put_disk(gd);
 err: