lightnvm: pblk: fix resubmission of overwritten write err lbas

[ Upstream commit c12fa401ac8c94a74aff68bb5736b3f1dc695fa8 ]

Make sure we only look up valid lba addresses on the resubmission path.

If an lba is invalidated in the write buffer, that sector will be
submitted to disk (as it is already mapped to a ppa), and that write
might fail, resulting in a crash when trying to look up the lba in the
mapping table (as the lba is marked as invalid).
Signed-off-by: NHans Holmberg <hans.holmberg@cnexlabs.com>
Reviewed-by: NJavier González <javier@javigon.com>
Signed-off-by: NMatias Bjørling <mb@lightnvm.io>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NSasha Levin <sashal@kernel.org>

drivers/lightnvm/pblk-write.c

@@ -158,9 +158,11 @@ static void pblk_prepare_resubmit(struct pblk *pblk, unsigned int sentry,
 		w_ctx = &entry->w_ctx;
 
 		/* Check if the lba has been overwritten */
-		ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
-		if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
-			w_ctx->lba = ADDR_EMPTY;
+		if (w_ctx->lba != ADDR_EMPTY) {
+			ppa_l2p = pblk_trans_map_get(pblk, w_ctx->lba);
+			if (!pblk_ppa_comp(ppa_l2p, entry->cacheline))
+				w_ctx->lba = ADDR_EMPTY;
+		}
 
 		/* Mark up the entry as submittable again */
 		flags = READ_ONCE(w_ctx->flags);