lightnvm: make ppa_list const in nvm_set_rqd_list

The passed by reference ppa list in nvm_set_rqd_list() is updated when
multiple planes are available. In that case, each PPA plane is
incremented when the device side PPA list is created. This prevents the
caller to rely on the PPA list to be unmodified after a call.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index ddc8098..00b64f7 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -237,9 +237,10 @@
 EXPORT_SYMBOL(nvm_generic_to_addr_mode);
 
 int nvm_set_rqd_ppalist(struct nvm_dev *dev, struct nvm_rq *rqd,
-				struct ppa_addr *ppas, int nr_ppas, int vblk)
+			const struct ppa_addr *ppas, int nr_ppas, int vblk)
 {
 	int i, plane_cnt, pl_idx;
+	struct ppa_addr ppa;
 
 	if ((!vblk || dev->plane_mode == NVM_PLANE_SINGLE) && nr_ppas == 1) {
 		rqd->nr_ppas = nr_ppas;
@@ -264,8 +265,9 @@
 
 		for (i = 0; i < nr_ppas; i++) {
 			for (pl_idx = 0; pl_idx < plane_cnt; pl_idx++) {
-				ppas[i].g.pl = pl_idx;
-				rqd->ppa_list[(pl_idx * nr_ppas) + i] = ppas[i];
+				ppa = ppas[i];
+				ppa.g.pl = pl_idx;
+				rqd->ppa_list[(pl_idx * nr_ppas) + i] = ppa;
 			}
 		}
 	}