[PATCH 2/2] lightNVM: register bm in nvm_create_target if dev->bm is NULL

[Dongsheng Yang]

When we create target, we need to make sure dev->bm is not NULL.
If it's NULL try to register bm again. If we still fail to find
a proper bm for this dev, return error rather than continue to
provide a NULL pointer dereference problem later.

Signed-off-by: Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx>
---
 drivers/lightnvm/core.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 5e4c2b8..9c75ea4 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -293,10 +293,30 @@ static int nvm_create_target(struct nvm_dev *dev, char *ttname, char *tname,
 						int lun_begin, int lun_end)
 {
 	struct request_queue *tqueue;
+	struct nvm_bm_type *bt;
 	struct gendisk *tdisk;
 	struct nvm_tgt_type *tt;
 	struct nvm_target *t;
 	void *targetdata;
+	int ret = 0;
+
+	if (!dev->bm) {
+		/* register with device with a supported BM */
+		list_for_each_entry(bt, &nvm_bms, list) {
+			ret = bt->register_bm(dev);
+			if (ret < 0)
+				return ret; /* initialization failed */
+			if (ret > 0) {
+				dev->bm = bt;
+				break; /* successfully initialized */
+			}
+		}
+
+		if (!ret) {
+			pr_info("nvm: no compatible bm was found.\n");
+			return -ENODEV;
+		}
+	}
 
 	tt = nvm_find_target_type(ttname);
 	if (!tt) {
-- 
1.8.4.2


--------------000500080007030902000901
Content-Type: text/x-patch;
	name="0001-lightNVM-fix-a-compatibility-problem-in-compiling.patch"
Content-Transfer-Encoding: 8bit
Content-Disposition: attachment;
	filename="0001-lightNVM-fix-a-compatibility-problem-in-compiling.patch"