lightnvm: don't print a warning for ADDR_EMPTY

Reading from ADDR_EMPTY is out of bounds.  The current code generates a
static checker warning because we check for out of bounds "lba" before
we check for ADDR_EMPTY, so the second check is always false.  It looks
like we intended ADDR_EMPTY to be a no-op without printing a warning.

Fixes: a4bd217 ("lightnvm: physical block device (pblk) target")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/lightnvm/pblk-read.c

@@ -410,15 +410,15 @@ static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 	struct ppa_addr ppa;
 	int valid_secs = 0;
 
+	if (lba == ADDR_EMPTY)
+		goto out;
+
 	/* logic error: lba out-of-bounds */
 	if (lba >= pblk->rl.nr_secs) {
 		WARN(1, "pblk: read lba out of bounds\n");
 		goto out;
 	}
 
-	if (lba == ADDR_EMPTY)
-		goto out;
-
 	spin_lock(&pblk->trans_lock);
 	ppa = pblk_trans_map_get(pblk, lba);
 	spin_unlock(&pblk->trans_lock);