nvme: make sure ns head inherits underlying device limits

[ Upstream commit 8f676b8508c250bbe255096522fdefb73f1ea0b9 ]

Whenever we update ns_head info, we need to make sure it is still
compatible with all underlying backing devices because although nvme
multipath doesn't have any explicit use of these limits, other devices
can still be stacked on top of it which may rely on the underlying limits.
Start with unlimited stacking limits, and every info update iterate over
siblings and adjust queue limits.
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NSasha Levin <sashal@kernel.org>

drivers/nvme/host/core.c

@@ -1519,8 +1519,10 @@ static void __nvme_revalidate_disk(struct gendisk *disk, struct nvme_id_ns *id)
 	if (ns->ndev)
 		nvme_nvm_update_nvm_info(ns);
 #ifdef CONFIG_NVME_MULTIPATH
-	if (ns->head->disk)
+	if (ns->head->disk) {
 		nvme_update_disk_info(ns->head->disk, ns, id);
+		blk_queue_stack_limits(ns->head->disk->queue, ns->queue);
+	}
 #endif
 }
 

drivers/nvme/host/multipath.c

@@ -257,6 +257,7 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
 	/* set to a default value for 512 until disk is validated */
 	blk_queue_logical_block_size(q, 512);
+	blk_set_stacking_limits(&q->limits);
 
 	/* we need to propagate up the VMC settings */
 	if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)