lightnvm: pblk: simplify meta. memory allocation

smeta size will always be suitable for a kmalloc allocation. Simplify
the code and leave the vmalloc fallback only for emeta, where the pblk
configuration has an impact.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
index a29a347..3db2cbe 100644
--- a/drivers/lightnvm/pblk-write.c
+++ b/drivers/lightnvm/pblk-write.c
@@ -442,7 +442,8 @@ int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 	list_add(&meta_line->list, &meta_line->list);
 	spin_unlock(&l_mg->close_lock);
 fail_free_bio:
-	bio_put(bio);
+	if (likely(l_mg->emeta_alloc_type == PBLK_VMALLOC_META))
+		bio_put(bio);
 fail_free_rqd:
 	pblk_free_rqd(pblk, rqd, READ);
 	return ret;