Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 930 insertions, 0 deletions

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
new file mode 100644
index 000000000..f96d330d3
--- /dev/null
+++ b/drivers/nvme/host/multipath.c
@@ -0,0 +1,930 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2017-2018 Christoph Hellwig.
+ */
+
+#include <linux/backing-dev.h>
+#include <linux/moduleparam.h>
+#include <linux/vmalloc.h>
+#include <trace/events/block.h>
+#include "nvme.h"
+
+bool multipath = true;
+module_param(multipath, bool, 0444);
+MODULE_PARM_DESC(multipath,
+	"turn on native support for multiple controllers per subsystem");
+
+static const char *nvme_iopolicy_names[] = {
+	[NVME_IOPOLICY_NUMA]	= "numa",
+	[NVME_IOPOLICY_RR]	= "round-robin",
+};
+
+static int iopolicy = NVME_IOPOLICY_NUMA;
+
+static int nvme_set_iopolicy(const char *val, const struct kernel_param *kp)
+{
+	if (!val)
+		return -EINVAL;
+	if (!strncmp(val, "numa", 4))
+		iopolicy = NVME_IOPOLICY_NUMA;
+	else if (!strncmp(val, "round-robin", 11))
+		iopolicy = NVME_IOPOLICY_RR;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int nvme_get_iopolicy(char *buf, const struct kernel_param *kp)
+{
+	return sprintf(buf, "%s\n", nvme_iopolicy_names[iopolicy]);
+}
+
+module_param_call(iopolicy, nvme_set_iopolicy, nvme_get_iopolicy,
+	&iopolicy, 0644);
+MODULE_PARM_DESC(iopolicy,
+	"Default multipath I/O policy; 'numa' (default) or 'round-robin'");
+
+void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys)
+{
+	subsys->iopolicy = iopolicy;
+}
+
+void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
+{
+	struct nvme_ns_head *h;
+
+	lockdep_assert_held(&subsys->lock);
+	list_for_each_entry(h, &subsys->nsheads, entry)
+		if (h->disk)
+			blk_mq_unfreeze_queue(h->disk->queue);
+}
+
+void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys)
+{
+	struct nvme_ns_head *h;
+
+	lockdep_assert_held(&subsys->lock);
+	list_for_each_entry(h, &subsys->nsheads, entry)
+		if (h->disk)
+			blk_mq_freeze_queue_wait(h->disk->queue);
+}
+
+void nvme_mpath_start_freeze(struct nvme_subsystem *subsys)
+{
+	struct nvme_ns_head *h;
+
+	lockdep_assert_held(&subsys->lock);
+	list_for_each_entry(h, &subsys->nsheads, entry)
+		if (h->disk)
+			blk_freeze_queue_start(h->disk->queue);
+}
+
+void nvme_failover_req(struct request *req)
+{
+	struct nvme_ns *ns = req->q->queuedata;
+	u16 status = nvme_req(req)->status & 0x7ff;
+	unsigned long flags;
+	struct bio *bio;
+
+	nvme_mpath_clear_current_path(ns);
+
+	/*
+	 * If we got back an ANA error, we know the controller is alive but not
+	 * ready to serve this namespace.  Kick of a re-read of the ANA
+	 * information page, and just try any other available path for now.
+	 */
+	if (nvme_is_ana_error(status) && ns->ctrl->ana_log_buf) {
+		set_bit(NVME_NS_ANA_PENDING, &ns->flags);
+		queue_work(nvme_wq, &ns->ctrl->ana_work);
+	}
+
+	spin_lock_irqsave(&ns->head->requeue_lock, flags);
+	for (bio = req->bio; bio; bio = bio->bi_next) {
+		bio_set_dev(bio, ns->head->disk->part0);
+		if (bio->bi_opf & REQ_POLLED) {
+			bio->bi_opf &= ~REQ_POLLED;
+			bio->bi_cookie = BLK_QC_T_NONE;
+		}
+	}
+	blk_steal_bios(&ns->head->requeue_list, req);
+	spin_unlock_irqrestore(&ns->head->requeue_lock, flags);
+
+	blk_mq_end_request(req, 0);
+	kblockd_schedule_work(&ns->head->requeue_work);
+}
+
+void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
+{
+	struct nvme_ns *ns;
+
+	down_read(&ctrl->namespaces_rwsem);
+	list_for_each_entry(ns, &ctrl->namespaces, list) {
+		if (!ns->head->disk)
+			continue;
+		kblockd_schedule_work(&ns->head->requeue_work);
+		if (ctrl->state == NVME_CTRL_LIVE)
+			disk_uevent(ns->head->disk, KOBJ_CHANGE);
+	}
+	up_read(&ctrl->namespaces_rwsem);
+}
+
+static const char *nvme_ana_state_names[] = {
+	[0]				= "invalid state",
+	[NVME_ANA_OPTIMIZED]		= "optimized",
+	[NVME_ANA_NONOPTIMIZED]		= "non-optimized",
+	[NVME_ANA_INACCESSIBLE]		= "inaccessible",
+	[NVME_ANA_PERSISTENT_LOSS]	= "persistent-loss",
+	[NVME_ANA_CHANGE]		= "change",
+};
+
+bool nvme_mpath_clear_current_path(struct nvme_ns *ns)
+{
+	struct nvme_ns_head *head = ns->head;
+	bool changed = false;
+	int node;
+
+	if (!head)
+		goto out;
+
+	for_each_node(node) {
+		if (ns == rcu_access_pointer(head->current_path[node])) {
+			rcu_assign_pointer(head->current_path[node], NULL);
+			changed = true;
+		}
+	}
+out:
+	return changed;
+}
+
+void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)
+{
+	struct nvme_ns *ns;
+
+	down_read(&ctrl->namespaces_rwsem);
+	list_for_each_entry(ns, &ctrl->namespaces, list) {
+		nvme_mpath_clear_current_path(ns);
+		kblockd_schedule_work(&ns->head->requeue_work);
+	}
+	up_read(&ctrl->namespaces_rwsem);
+}
+
+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);
+	kblockd_schedule_work(&head->requeue_work);
+}
+
+static bool nvme_path_is_disabled(struct nvme_ns *ns)
+{
+	/*
+	 * We don't treat NVME_CTRL_DELETING as a disabled path as I/O should
+	 * still be able to complete assuming that the controller is connected.
+	 * Otherwise it will fail immediately and return to the requeue list.
+	 */
+	if (ns->ctrl->state != NVME_CTRL_LIVE &&
+	    ns->ctrl->state != NVME_CTRL_DELETING)
+		return true;
+	if (test_bit(NVME_NS_ANA_PENDING, &ns->flags) ||
+	    !test_bit(NVME_NS_READY, &ns->flags))
+		return true;
+	return false;
+}
+
+static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
+{
+	int found_distance = INT_MAX, fallback_distance = INT_MAX, distance;
+	struct nvme_ns *found = NULL, *fallback = NULL, *ns;
+
+	list_for_each_entry_rcu(ns, &head->list, siblings) {
+		if (nvme_path_is_disabled(ns))
+			continue;
+
+		if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
+			distance = node_distance(node, ns->ctrl->numa_node);
+		else
+			distance = LOCAL_DISTANCE;
+
+		switch (ns->ana_state) {
+		case NVME_ANA_OPTIMIZED:
+			if (distance < found_distance) {
+				found_distance = distance;
+				found = ns;
+			}
+			break;
+		case NVME_ANA_NONOPTIMIZED:
+			if (distance < fallback_distance) {
+				fallback_distance = distance;
+				fallback = ns;
+			}
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (!found)
+		found = fallback;
+	if (found)
+		rcu_assign_pointer(head->current_path[node], found);
+	return found;
+}
+
+static struct nvme_ns *nvme_next_ns(struct nvme_ns_head *head,
+		struct nvme_ns *ns)
+{
+	ns = list_next_or_null_rcu(&head->list, &ns->siblings, struct nvme_ns,
+			siblings);
+	if (ns)
+		return ns;
+	return list_first_or_null_rcu(&head->list, struct nvme_ns, siblings);
+}
+
+static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
+		int node, struct nvme_ns *old)
+{
+	struct nvme_ns *ns, *found = NULL;
+
+	if (list_is_singular(&head->list)) {
+		if (nvme_path_is_disabled(old))
+			return NULL;
+		return old;
+	}
+
+	for (ns = nvme_next_ns(head, old);
+	     ns && ns != old;
+	     ns = nvme_next_ns(head, ns)) {
+		if (nvme_path_is_disabled(ns))
+			continue;
+
+		if (ns->ana_state == NVME_ANA_OPTIMIZED) {
+			found = ns;
+			goto out;
+		}
+		if (ns->ana_state == NVME_ANA_NONOPTIMIZED)
+			found = ns;
+	}
+
+	/*
+	 * The loop above skips the current path for round-robin semantics.
+	 * Fall back to the current path if either:
+	 *  - no other optimized path found and current is optimized,
+	 *  - no other usable path found and current is usable.
+	 */
+	if (!nvme_path_is_disabled(old) &&
+	    (old->ana_state == NVME_ANA_OPTIMIZED ||
+	     (!found && old->ana_state == NVME_ANA_NONOPTIMIZED)))
+		return old;
+
+	if (!found)
+		return NULL;
+out:
+	rcu_assign_pointer(head->current_path[node], found);
+	return found;
+}
+
+static inline bool nvme_path_is_optimized(struct nvme_ns *ns)
+{
+	return ns->ctrl->state == NVME_CTRL_LIVE &&
+		ns->ana_state == NVME_ANA_OPTIMIZED;
+}
+
+inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
+{
+	int node = numa_node_id();
+	struct nvme_ns *ns;
+
+	ns = srcu_dereference(head->current_path[node], &head->srcu);
+	if (unlikely(!ns))
+		return __nvme_find_path(head, node);
+
+	if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR)
+		return nvme_round_robin_path(head, node, ns);
+	if (unlikely(!nvme_path_is_optimized(ns)))
+		return __nvme_find_path(head, node);
+	return ns;
+}
+
+static bool nvme_available_path(struct nvme_ns_head *head)
+{
+	struct nvme_ns *ns;
+
+	list_for_each_entry_rcu(ns, &head->list, siblings) {
+		if (test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ns->ctrl->flags))
+			continue;
+		switch (ns->ctrl->state) {
+		case NVME_CTRL_LIVE:
+		case NVME_CTRL_RESETTING:
+		case NVME_CTRL_CONNECTING:
+			/* fallthru */
+			return true;
+		default:
+			break;
+		}
+	}
+	return false;
+}
+
+static void nvme_ns_head_submit_bio(struct bio *bio)
+{
+	struct nvme_ns_head *head = bio->bi_bdev->bd_disk->private_data;
+	struct device *dev = disk_to_dev(head->disk);
+	struct nvme_ns *ns;
+	int srcu_idx;
+
+	/*
+	 * The namespace might be going away and the bio might be moved to a
+	 * different queue via blk_steal_bios(), so we need to use the bio_split
+	 * pool from the original queue to allocate the bvecs from.
+	 */
+	bio = bio_split_to_limits(bio);
+	if (!bio)
+		return;
+
+	srcu_idx = srcu_read_lock(&head->srcu);
+	ns = nvme_find_path(head);
+	if (likely(ns)) {
+		bio_set_dev(bio, ns->disk->part0);
+		bio->bi_opf |= REQ_NVME_MPATH;
+		trace_block_bio_remap(bio, disk_devt(ns->head->disk),
+				      bio->bi_iter.bi_sector);
+		submit_bio_noacct(bio);
+	} else if (nvme_available_path(head)) {
+		dev_warn_ratelimited(dev, "no usable path - requeuing I/O\n");
+
+		spin_lock_irq(&head->requeue_lock);
+		bio_list_add(&head->requeue_list, bio);
+		spin_unlock_irq(&head->requeue_lock);
+	} else {
+		dev_warn_ratelimited(dev, "no available path - failing I/O\n");
+
+		bio_io_error(bio);
+	}
+
+	srcu_read_unlock(&head->srcu, srcu_idx);
+}
+
+static int nvme_ns_head_open(struct block_device *bdev, fmode_t mode)
+{
+	if (!nvme_tryget_ns_head(bdev->bd_disk->private_data))
+		return -ENXIO;
+	return 0;
+}
+
+static void nvme_ns_head_release(struct gendisk *disk, fmode_t mode)
+{
+	nvme_put_ns_head(disk->private_data);
+}
+
+#ifdef CONFIG_BLK_DEV_ZONED
+static int nvme_ns_head_report_zones(struct gendisk *disk, sector_t sector,
+		unsigned int nr_zones, report_zones_cb cb, void *data)
+{
+	struct nvme_ns_head *head = disk->private_data;
+	struct nvme_ns *ns;
+	int srcu_idx, ret = -EWOULDBLOCK;
+
+	srcu_idx = srcu_read_lock(&head->srcu);
+	ns = nvme_find_path(head);
+	if (ns)
+		ret = nvme_ns_report_zones(ns, sector, nr_zones, cb, data);
+	srcu_read_unlock(&head->srcu, srcu_idx);
+	return ret;
+}
+#else
+#define nvme_ns_head_report_zones	NULL
+#endif /* CONFIG_BLK_DEV_ZONED */
+
+const struct block_device_operations nvme_ns_head_ops = {
+	.owner		= THIS_MODULE,
+	.submit_bio	= nvme_ns_head_submit_bio,
+	.open		= nvme_ns_head_open,
+	.release	= nvme_ns_head_release,
+	.ioctl		= nvme_ns_head_ioctl,
+	.compat_ioctl	= blkdev_compat_ptr_ioctl,
+	.getgeo		= nvme_getgeo,
+	.report_zones	= nvme_ns_head_report_zones,
+	.pr_ops		= &nvme_pr_ops,
+};
+
+static inline struct nvme_ns_head *cdev_to_ns_head(struct cdev *cdev)
+{
+	return container_of(cdev, struct nvme_ns_head, cdev);
+}
+
+static int nvme_ns_head_chr_open(struct inode *inode, struct file *file)
+{
+	if (!nvme_tryget_ns_head(cdev_to_ns_head(inode->i_cdev)))
+		return -ENXIO;
+	return 0;
+}
+
+static int nvme_ns_head_chr_release(struct inode *inode, struct file *file)
+{
+	nvme_put_ns_head(cdev_to_ns_head(inode->i_cdev));
+	return 0;
+}
+
+static const struct file_operations nvme_ns_head_chr_fops = {
+	.owner		= THIS_MODULE,
+	.open		= nvme_ns_head_chr_open,
+	.release	= nvme_ns_head_chr_release,
+	.unlocked_ioctl	= nvme_ns_head_chr_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.uring_cmd	= nvme_ns_head_chr_uring_cmd,
+	.uring_cmd_iopoll = nvme_ns_head_chr_uring_cmd_iopoll,
+};
+
+static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
+{
+	int ret;
+
+	head->cdev_device.parent = &head->subsys->dev;
+	ret = dev_set_name(&head->cdev_device, "ng%dn%d",
+			   head->subsys->instance, head->instance);
+	if (ret)
+		return ret;
+	ret = nvme_cdev_add(&head->cdev, &head->cdev_device,
+			    &nvme_ns_head_chr_fops, THIS_MODULE);
+	return ret;
+}
+
+static void nvme_requeue_work(struct work_struct *work)
+{
+	struct nvme_ns_head *head =
+		container_of(work, struct nvme_ns_head, requeue_work);
+	struct bio *bio, *next;
+
+	spin_lock_irq(&head->requeue_lock);
+	next = bio_list_get(&head->requeue_list);
+	spin_unlock_irq(&head->requeue_lock);
+
+	while ((bio = next) != NULL) {
+		next = bio->bi_next;
+		bio->bi_next = NULL;
+
+		submit_bio_noacct(bio);
+	}
+}
+
+int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
+{
+	bool vwc = false;
+
+	mutex_init(&head->lock);
+	bio_list_init(&head->requeue_list);
+	spin_lock_init(&head->requeue_lock);
+	INIT_WORK(&head->requeue_work, nvme_requeue_work);
+
+	/*
+	 * Add a multipath node if the subsystems supports multiple controllers.
+	 * We also do this for private namespaces as the namespace sharing flag
+	 * could change after a rescan.
+	 */
+	if (!(ctrl->subsys->cmic & NVME_CTRL_CMIC_MULTI_CTRL) ||
+	    !nvme_is_unique_nsid(ctrl, head) || !multipath)
+		return 0;
+
+	head->disk = blk_alloc_disk(ctrl->numa_node);
+	if (!head->disk)
+		return -ENOMEM;
+	head->disk->fops = &nvme_ns_head_ops;
+	head->disk->private_data = head;
+	sprintf(head->disk->disk_name, "nvme%dn%d",
+			ctrl->subsys->instance, head->instance);
+
+	blk_queue_flag_set(QUEUE_FLAG_NONROT, head->disk->queue);
+	blk_queue_flag_set(QUEUE_FLAG_NOWAIT, head->disk->queue);
+	/*
+	 * This assumes all controllers that refer to a namespace either
+	 * support poll queues or not.  That is not a strict guarantee,
+	 * but if the assumption is wrong the effect is only suboptimal
+	 * performance but not correctness problem.
+	 */
+	if (ctrl->tagset->nr_maps > HCTX_TYPE_POLL &&
+	    ctrl->tagset->map[HCTX_TYPE_POLL].nr_queues)
+		blk_queue_flag_set(QUEUE_FLAG_POLL, head->disk->queue);
+
+	/* set to a default value of 512 until the disk is validated */
+	blk_queue_logical_block_size(head->disk->queue, 512);
+	blk_set_stacking_limits(&head->disk->queue->limits);
+	blk_queue_dma_alignment(head->disk->queue, 3);
+
+	/* we need to propagate up the VMC settings */
+	if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
+		vwc = true;
+	blk_queue_write_cache(head->disk->queue, vwc, vwc);
+	return 0;
+}
+
+static void nvme_mpath_set_live(struct nvme_ns *ns)
+{
+	struct nvme_ns_head *head = ns->head;
+	int rc;
+
+	if (!head->disk)
+		return;
+
+	/*
+	 * test_and_set_bit() is used because it is protecting against two nvme
+	 * paths simultaneously calling device_add_disk() on the same namespace
+	 * head.
+	 */
+	if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
+		rc = device_add_disk(&head->subsys->dev, head->disk,
+				     nvme_ns_id_attr_groups);
+		if (rc) {
+			clear_bit(NVME_NSHEAD_DISK_LIVE, &ns->flags);
+			return;
+		}
+		nvme_add_ns_head_cdev(head);
+	}
+
+	mutex_lock(&head->lock);
+	if (nvme_path_is_optimized(ns)) {
+		int node, srcu_idx;
+
+		srcu_idx = srcu_read_lock(&head->srcu);
+		for_each_node(node)
+			__nvme_find_path(head, node);
+		srcu_read_unlock(&head->srcu, srcu_idx);
+	}
+	mutex_unlock(&head->lock);
+
+	synchronize_srcu(&head->srcu);
+	kblockd_schedule_work(&head->requeue_work);
+}
+
+static int nvme_parse_ana_log(struct nvme_ctrl *ctrl, void *data,
+		int (*cb)(struct nvme_ctrl *ctrl, struct nvme_ana_group_desc *,
+			void *))
+{
+	void *base = ctrl->ana_log_buf;
+	size_t offset = sizeof(struct nvme_ana_rsp_hdr);
+	int error, i;
+
+	lockdep_assert_held(&ctrl->ana_lock);
+
+	for (i = 0; i < le16_to_cpu(ctrl->ana_log_buf->ngrps); i++) {
+		struct nvme_ana_group_desc *desc = base + offset;
+		u32 nr_nsids;
+		size_t nsid_buf_size;
+
+		if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
+			return -EINVAL;
+
+		nr_nsids = le32_to_cpu(desc->nnsids);
+		nsid_buf_size = flex_array_size(desc, nsids, nr_nsids);
+
+		if (WARN_ON_ONCE(desc->grpid == 0))
+			return -EINVAL;
+		if (WARN_ON_ONCE(le32_to_cpu(desc->grpid) > ctrl->anagrpmax))
+			return -EINVAL;
+		if (WARN_ON_ONCE(desc->state == 0))
+			return -EINVAL;
+		if (WARN_ON_ONCE(desc->state > NVME_ANA_CHANGE))
+			return -EINVAL;
+
+		offset += sizeof(*desc);
+		if (WARN_ON_ONCE(offset > ctrl->ana_log_size - nsid_buf_size))
+			return -EINVAL;
+
+		error = cb(ctrl, desc, data);
+		if (error)
+			return error;
+
+		offset += nsid_buf_size;
+	}
+
+	return 0;
+}
+
+static inline bool nvme_state_is_live(enum nvme_ana_state state)
+{
+	return state == NVME_ANA_OPTIMIZED || state == NVME_ANA_NONOPTIMIZED;
+}
+
+static void nvme_update_ns_ana_state(struct nvme_ana_group_desc *desc,
+		struct nvme_ns *ns)
+{
+	ns->ana_grpid = le32_to_cpu(desc->grpid);
+	ns->ana_state = desc->state;
+	clear_bit(NVME_NS_ANA_PENDING, &ns->flags);
+	/*
+	 * nvme_mpath_set_live() will trigger I/O to the multipath path device
+	 * and in turn to this path device.  However we cannot accept this I/O
+	 * if the controller is not live.  This may deadlock if called from
+	 * nvme_mpath_init_identify() and the ctrl will never complete
+	 * initialization, preventing I/O from completing.  For this case we
+	 * will reprocess the ANA log page in nvme_mpath_update() once the
+	 * controller is ready.
+	 */
+	if (nvme_state_is_live(ns->ana_state) &&
+	    ns->ctrl->state == NVME_CTRL_LIVE)
+		nvme_mpath_set_live(ns);
+}
+
+static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
+		struct nvme_ana_group_desc *desc, void *data)
+{
+	u32 nr_nsids = le32_to_cpu(desc->nnsids), n = 0;
+	unsigned *nr_change_groups = data;
+	struct nvme_ns *ns;
+
+	dev_dbg(ctrl->device, "ANA group %d: %s.\n",
+			le32_to_cpu(desc->grpid),
+			nvme_ana_state_names[desc->state]);
+
+	if (desc->state == NVME_ANA_CHANGE)
+		(*nr_change_groups)++;
+
+	if (!nr_nsids)
+		return 0;
+
+	down_read(&ctrl->namespaces_rwsem);
+	list_for_each_entry(ns, &ctrl->namespaces, list) {
+		unsigned nsid;
+again:
+		nsid = le32_to_cpu(desc->nsids[n]);
+		if (ns->head->ns_id < nsid)
+			continue;
+		if (ns->head->ns_id == nsid)
+			nvme_update_ns_ana_state(desc, ns);
+		if (++n == nr_nsids)
+			break;
+		if (ns->head->ns_id > nsid)
+			goto again;
+	}
+	up_read(&ctrl->namespaces_rwsem);
+	return 0;
+}
+
+static int nvme_read_ana_log(struct nvme_ctrl *ctrl)
+{
+	u32 nr_change_groups = 0;
+	int error;
+
+	mutex_lock(&ctrl->ana_lock);
+	error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA, 0, NVME_CSI_NVM,
+			ctrl->ana_log_buf, ctrl->ana_log_size, 0);
+	if (error) {
+		dev_warn(ctrl->device, "Failed to get ANA log: %d\n", error);
+		goto out_unlock;
+	}
+
+	error = nvme_parse_ana_log(ctrl, &nr_change_groups,
+			nvme_update_ana_state);
+	if (error)
+		goto out_unlock;
+
+	/*
+	 * In theory we should have an ANATT timer per group as they might enter
+	 * the change state at different times.  But that is a lot of overhead
+	 * just to protect against a target that keeps entering new changes
+	 * states while never finishing previous ones.  But we'll still
+	 * eventually time out once all groups are in change state, so this
+	 * isn't a big deal.
+	 *
+	 * We also double the ANATT value to provide some slack for transports
+	 * or AEN processing overhead.
+	 */
+	if (nr_change_groups)
+		mod_timer(&ctrl->anatt_timer, ctrl->anatt * HZ * 2 + jiffies);
+	else
+		del_timer_sync(&ctrl->anatt_timer);
+out_unlock:
+	mutex_unlock(&ctrl->ana_lock);
+	return error;
+}
+
+static void nvme_ana_work(struct work_struct *work)
+{
+	struct nvme_ctrl *ctrl = container_of(work, struct nvme_ctrl, ana_work);
+
+	if (ctrl->state != NVME_CTRL_LIVE)
+		return;
+
+	nvme_read_ana_log(ctrl);
+}
+
+void nvme_mpath_update(struct nvme_ctrl *ctrl)
+{
+	u32 nr_change_groups = 0;
+
+	if (!ctrl->ana_log_buf)
+		return;
+
+	mutex_lock(&ctrl->ana_lock);
+	nvme_parse_ana_log(ctrl, &nr_change_groups, nvme_update_ana_state);
+	mutex_unlock(&ctrl->ana_lock);
+}
+
+static void nvme_anatt_timeout(struct timer_list *t)
+{
+	struct nvme_ctrl *ctrl = from_timer(ctrl, t, anatt_timer);
+
+	dev_info(ctrl->device, "ANATT timeout, resetting controller.\n");
+	nvme_reset_ctrl(ctrl);
+}
+
+void nvme_mpath_stop(struct nvme_ctrl *ctrl)
+{
+	if (!nvme_ctrl_use_ana(ctrl))
+		return;
+	del_timer_sync(&ctrl->anatt_timer);
+	cancel_work_sync(&ctrl->ana_work);
+}
+
+#define SUBSYS_ATTR_RW(_name, _mode, _show, _store)  \
+	struct device_attribute subsys_attr_##_name =	\
+		__ATTR(_name, _mode, _show, _store)
+
+static ssize_t nvme_subsys_iopolicy_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvme_subsystem *subsys =
+		container_of(dev, struct nvme_subsystem, dev);
+
+	return sysfs_emit(buf, "%s\n",
+			  nvme_iopolicy_names[READ_ONCE(subsys->iopolicy)]);
+}
+
+static ssize_t nvme_subsys_iopolicy_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct nvme_subsystem *subsys =
+		container_of(dev, struct nvme_subsystem, dev);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(nvme_iopolicy_names); i++) {
+		if (sysfs_streq(buf, nvme_iopolicy_names[i])) {
+			WRITE_ONCE(subsys->iopolicy, i);
+			return count;
+		}
+	}
+
+	return -EINVAL;
+}
+SUBSYS_ATTR_RW(iopolicy, S_IRUGO | S_IWUSR,
+		      nvme_subsys_iopolicy_show, nvme_subsys_iopolicy_store);
+
+static ssize_t ana_grpid_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	return sysfs_emit(buf, "%d\n", nvme_get_ns_from_dev(dev)->ana_grpid);
+}
+DEVICE_ATTR_RO(ana_grpid);
+
+static ssize_t ana_state_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
+
+	return sysfs_emit(buf, "%s\n", nvme_ana_state_names[ns->ana_state]);
+}
+DEVICE_ATTR_RO(ana_state);
+
+static int nvme_lookup_ana_group_desc(struct nvme_ctrl *ctrl,
+		struct nvme_ana_group_desc *desc, void *data)
+{
+	struct nvme_ana_group_desc *dst = data;
+
+	if (desc->grpid != dst->grpid)
+		return 0;
+
+	*dst = *desc;
+	return -ENXIO; /* just break out of the loop */
+}
+
+void nvme_mpath_add_disk(struct nvme_ns *ns, __le32 anagrpid)
+{
+	if (nvme_ctrl_use_ana(ns->ctrl)) {
+		struct nvme_ana_group_desc desc = {
+			.grpid = anagrpid,
+			.state = 0,
+		};
+
+		mutex_lock(&ns->ctrl->ana_lock);
+		ns->ana_grpid = le32_to_cpu(anagrpid);
+		nvme_parse_ana_log(ns->ctrl, &desc, nvme_lookup_ana_group_desc);
+		mutex_unlock(&ns->ctrl->ana_lock);
+		if (desc.state) {
+			/* found the group desc: update */
+			nvme_update_ns_ana_state(&desc, ns);
+		} else {
+			/* group desc not found: trigger a re-read */
+			set_bit(NVME_NS_ANA_PENDING, &ns->flags);
+			queue_work(nvme_wq, &ns->ctrl->ana_work);
+		}
+	} else {
+		ns->ana_state = NVME_ANA_OPTIMIZED;
+		nvme_mpath_set_live(ns);
+	}
+
+	if (blk_queue_stable_writes(ns->queue) && ns->head->disk)
+		blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES,
+				   ns->head->disk->queue);
+#ifdef CONFIG_BLK_DEV_ZONED
+	if (blk_queue_is_zoned(ns->queue) && ns->head->disk)
+		ns->head->disk->nr_zones = ns->disk->nr_zones;
+#endif
+}
+
+void nvme_mpath_shutdown_disk(struct nvme_ns_head *head)
+{
+	if (!head->disk)
+		return;
+	kblockd_schedule_work(&head->requeue_work);
+	if (test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
+		nvme_cdev_del(&head->cdev, &head->cdev_device);
+		del_gendisk(head->disk);
+	}
+}
+
+void nvme_mpath_remove_disk(struct nvme_ns_head *head)
+{
+	if (!head->disk)
+		return;
+	/* make sure all pending bios are cleaned up */
+	kblockd_schedule_work(&head->requeue_work);
+	flush_work(&head->requeue_work);
+	put_disk(head->disk);
+}
+
+void nvme_mpath_init_ctrl(struct nvme_ctrl *ctrl)
+{
+	mutex_init(&ctrl->ana_lock);
+	timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
+	INIT_WORK(&ctrl->ana_work, nvme_ana_work);
+}
+
+int nvme_mpath_init_identify(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
+{
+	size_t max_transfer_size = ctrl->max_hw_sectors << SECTOR_SHIFT;
+	size_t ana_log_size;
+	int error = 0;
+
+	/* check if multipath is enabled and we have the capability */
+	if (!multipath || !ctrl->subsys ||
+	    !(ctrl->subsys->cmic & NVME_CTRL_CMIC_ANA))
+		return 0;
+
+	if (!ctrl->max_namespaces ||
+	    ctrl->max_namespaces > le32_to_cpu(id->nn)) {
+		dev_err(ctrl->device,
+			"Invalid MNAN value %u\n", ctrl->max_namespaces);
+		return -EINVAL;
+	}
+
+	ctrl->anacap = id->anacap;
+	ctrl->anatt = id->anatt;
+	ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
+	ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);
+
+	ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
+		ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc) +
+		ctrl->max_namespaces * sizeof(__le32);
+	if (ana_log_size > max_transfer_size) {
+		dev_err(ctrl->device,
+			"ANA log page size (%zd) larger than MDTS (%zd).\n",
+			ana_log_size, max_transfer_size);
+		dev_err(ctrl->device, "disabling ANA support.\n");
+		goto out_uninit;
+	}
+	if (ana_log_size > ctrl->ana_log_size) {
+		nvme_mpath_stop(ctrl);
+		nvme_mpath_uninit(ctrl);
+		ctrl->ana_log_buf = kvmalloc(ana_log_size, GFP_KERNEL);
+		if (!ctrl->ana_log_buf)
+			return -ENOMEM;
+	}
+	ctrl->ana_log_size = ana_log_size;
+	error = nvme_read_ana_log(ctrl);
+	if (error)
+		goto out_uninit;
+	return 0;
+
+out_uninit:
+	nvme_mpath_uninit(ctrl);
+	return error;
+}
+
+void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
+{
+	kvfree(ctrl->ana_log_buf);
+	ctrl->ana_log_buf = NULL;
+	ctrl->ana_log_size = 0;
+}