lightnvm: pblk: set line bitmap check under debug

Do bitmap checks only when debug mode is enable. The line bitmap used
for mapping to physical addresses is fairly large (~512KB) and it is
expensive to do this checks on the fast path.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/lightnvm/pblk-core.c

@@ -1561,11 +1561,14 @@ static void pblk_line_should_sync_meta(struct pblk *pblk)
 void pblk_line_close(struct pblk *pblk, struct pblk_line *line)
 {
 	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
-	struct pblk_line_meta *lm = &pblk->lm;
 	struct list_head *move_list;
 
+#ifdef CONFIG_NVM_DEBUG
+	struct pblk_line_meta *lm = &pblk->lm;
+
 	WARN(!bitmap_full(line->map_bitmap, lm->sec_per_line),
 				"pblk: corrupt closed line %d\n", line->id);
+#endif
 
 	spin_lock(&l_mg->free_lock);
 	WARN_ON(!test_and_clear_bit(line->meta_line, &l_mg->meta_bitmap));