nvme: make nvme_identify_ns propagate errors back

right now callers of nvme_identify_ns only know that it failed,
but don't know why. Make nvme_identify_ns propagate the error back.
Because nvme_submit_sync_cmd may return a positive status code, we
make nvme_identify_ns receive the id by reference and return that
status up the call chain, but make sure not to leak positive nvme
status codes to the upper layers.
Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

drivers/nvme/host/core.c

@@ -1096,10 +1096,9 @@ static int nvme_identify_ns_list(struct nvme_ctrl *dev, unsigned nsid, __le32 *n
 				    NVME_IDENTIFY_DATA_SIZE);
 }
 
-static struct nvme_id_ns *nvme_identify_ns(struct nvme_ctrl *ctrl,
-		unsigned nsid)
+static int nvme_identify_ns(struct nvme_ctrl *ctrl,
+		unsigned nsid, struct nvme_id_ns **id)
 {
-	struct nvme_id_ns *id;
 	struct nvme_command c = { };
 	int error;
 
@@ -1108,18 +1107,17 @@ static struct nvme_id_ns *nvme_identify_ns(struct nvme_ctrl *ctrl,
 	c.identify.nsid = cpu_to_le32(nsid);
 	c.identify.cns = NVME_ID_CNS_NS;
 
-	id = kmalloc(sizeof(*id), GFP_KERNEL);
-	if (!id)
-		return NULL;
+	*id = kmalloc(sizeof(**id), GFP_KERNEL);
+	if (!*id)
+		return -ENOMEM;
 
-	error = nvme_submit_sync_cmd(ctrl->admin_q, &c, id, sizeof(*id));
+	error = nvme_submit_sync_cmd(ctrl->admin_q, &c, *id, sizeof(**id));
 	if (error) {
 		dev_warn(ctrl->device, "Identify namespace failed (%d)\n", error);
-		kfree(id);
-		return NULL;
+		kfree(*id);
 	}
 
-	return id;
+	return error;
 }
 
 static int nvme_features(struct nvme_ctrl *dev, u8 op, unsigned int fid,
@@ -1740,13 +1738,13 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 		return -ENODEV;
 	}
 
-	id = nvme_identify_ns(ctrl, ns->head->ns_id);
-	if (!id)
-		return -ENODEV;
+	ret = nvme_identify_ns(ctrl, ns->head->ns_id, &id);
+	if (ret)
+		goto out;
 
 	if (id->ncap == 0) {
 		ret = -ENODEV;
-		goto out;
+		goto free_id;
 	}
 
 	__nvme_revalidate_disk(disk, id);
@@ -1757,8 +1755,11 @@ static int nvme_revalidate_disk(struct gendisk *disk)
 		ret = -ENODEV;
 	}
 
-out:
+free_id:
 	kfree(id);
+out:
+	if (ret > 0)
+		ret = blk_status_to_errno(nvme_error_status(ret));
 	return ret;
 }
 
@@ -3329,11 +3330,9 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	blk_queue_logical_block_size(ns->queue, 1 << ns->lba_shift);
 	nvme_set_queue_limits(ctrl, ns->queue);
 
-	id = nvme_identify_ns(ctrl, nsid);
-	if (!id) {
-		ret = -EIO;
+	ret = nvme_identify_ns(ctrl, nsid, &id);
+	if (ret)
 		goto out_free_queue;
-	}
 
 	if (id->ncap == 0) {
 		ret = -EINVAL;
@@ -3395,6 +3394,8 @@ static int nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 	blk_cleanup_queue(ns->queue);
  out_free_ns:
 	kfree(ns);
+	if (ret > 0)
+		ret = blk_status_to_errno(nvme_error_status(ret));
 	return ret;
 }