btrfs: remove pointless local variable in lock_stripe_add()

In lock_stripe_add() we're caching the bucket for the stripe hash table
just for a single call to dereference the stripe hash.

If we just directly call rbio_bucket() we can safe the pointless local
variable.

Also move the dereferencing of the stripe hash outside of the variable
declaration block to not break over the 80 characters limit.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/raid56.c

@@ -671,8 +671,7 @@ static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
  */
 static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
 {
-	int bucket = rbio_bucket(rbio);
-	struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
+	struct btrfs_stripe_hash *h;
 	struct btrfs_raid_bio *cur;
 	struct btrfs_raid_bio *pending;
 	unsigned long flags;
@@ -680,6 +679,8 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
 	struct btrfs_raid_bio *cache_drop = NULL;
 	int ret = 0;
 
+	h = rbio->fs_info->stripe_hash_table->table + rbio_bucket(rbio);
+
 	spin_lock_irqsave(&h->lock, flags);
 	list_for_each_entry(cur, &h->hash_list, hash_list) {
 		if (cur->bbio->raid_map[0] != rbio->bbio->raid_map[0])