lightnvm: allow to init targets on factory mode

Target initialization has two responsibilities: creating the target
partition and instantiating the target. This patch enables to create a
factory partition (e.g., do not trigger recovery on the given target).
This is useful for target development and for being able to restore the
device state at any moment in time without requiring a full-device
erase.

Signed-off-by: Javier González <[e-mail]>
Signed-off-by: Matias Bjørling <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

drivers/lightnvm/core.c

···
 	tdisk->fops = &nvm_fops;
 	tdisk->queue = tqueue;
 
-	targetdata = tt->init(tgt_dev, tdisk);
+	targetdata = tt->init(tgt_dev, tdisk, create->flags);
 	if (IS_ERR(targetdata))
 		goto err_init;
 
···
 	create.tgtname[DISK_NAME_LEN - 1] = '\0';
 
 	if (create.flags != 0) {
-		pr_err("nvm: no flags supported\n");
-		return -EINVAL;
+		__u32 flags = create.flags;
+
+		/* Check for valid flags */
+		if (flags & NVM_TARGET_FACTORY)
+			flags &= ~NVM_TARGET_FACTORY;
+
+		if (flags) {
+			pr_err("nvm: flag not supported\n");
+			return -EINVAL;
+		}
 	}
 
 	return __nvm_configure_create(&create);

drivers/lightnvm/rrpc.c

···
 
 static struct nvm_tgt_type tt_rrpc;
 
-static void *rrpc_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk)
+static void *rrpc_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
+		       int flags)
 {
 	struct request_queue *bqueue = dev->q;
 	struct request_queue *tqueue = tdisk->queue;

include/linux/lightnvm.h

···
 
 typedef blk_qc_t (nvm_tgt_make_rq_fn)(struct request_queue *, struct bio *);
 typedef sector_t (nvm_tgt_capacity_fn)(void *);
-typedef void *(nvm_tgt_init_fn)(struct nvm_tgt_dev *, struct gendisk *);
+typedef void *(nvm_tgt_init_fn)(struct nvm_tgt_dev *, struct gendisk *,
+				int flags);
 typedef void (nvm_tgt_exit_fn)(void *);
 typedef int (nvm_tgt_sysfs_init_fn)(struct gendisk *);
 typedef void (nvm_tgt_sysfs_exit_fn)(struct gendisk *);

include/uapi/linux/lightnvm.h

···
 	};
 };
 
+enum {
+	NVM_TARGET_FACTORY = 1 << 0,	/* Init target in factory mode */
+};
+
 struct nvm_ioctl_create {
 	char dev[DISK_NAME_LEN];		/* open-channel SSD device */
 	char tgttype[NVM_TTYPE_NAME_MAX];	/* target type name */