Merge tag 'nvme-6.1-2022-01-02' of git://git.infradead.org/nvme into block-6.1

Pull NVMe fixes from Christoph:

"nvme fixes for Linux 6.1

 - fix SRCU protection of nvme_ns_head list (Caleb Sander)
 - clear the prp2 field when not used (Lei Rao)"

* tag 'nvme-6.1-2022-01-02' of git://git.infradead.org/nvme:
  nvme: fix SRCU protection of nvme_ns_head list
  nvme-pci: clear the prp2 field when not used

Author: axboe

drivers/nvme/host/core.c

@@ -4304,7 +4304,7 @@ static void nvme_ns_remove(struct nvme_ns *ns)
 	mutex_unlock(&ns->ctrl->subsys->lock);
 
 	/* guarantee not available in head->list */
-	synchronize_rcu();
+	synchronize_srcu(&ns->head->srcu);
 
 	if (!nvme_ns_head_multipath(ns->head))
 		nvme_cdev_del(&ns->cdev, &ns->cdev_device);

drivers/nvme/host/multipath.c

@@ -174,11 +174,14 @@ void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
 	struct nvme_ns_head *head = ns->head;
 	sector_t capacity = get_capacity(head->disk);
 	int node;
+	int srcu_idx;
 
+	srcu_idx = srcu_read_lock(&head->srcu);
 	list_for_each_entry_rcu(ns, &head->list, siblings) {
 		if (capacity != get_capacity(ns->disk))
 			clear_bit(NVME_NS_READY, &ns->flags);
 	}
+	srcu_read_unlock(&head->srcu, srcu_idx);
 
 	for_each_node(node)
 		rcu_assign_pointer(head->current_path[node], NULL);

drivers/nvme/host/pci.c

@@ -797,6 +797,8 @@ static blk_status_t nvme_setup_prp_simple(struct nvme_dev *dev,
 	cmnd->dptr.prp1 = cpu_to_le64(iod->first_dma);
 	if (bv->bv_len > first_prp_len)
 		cmnd->dptr.prp2 = cpu_to_le64(iod->first_dma + first_prp_len);
+	else
+		cmnd->dptr.prp2 = 0;
 	return BLK_STS_OK;
 }