blob: 74896be40c17699f5f2453620abaaae02b56fcb7 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2017-2018 Christoph Hellwig.
*/
#include <linux/backing-dev.h>
#include <linux/moduleparam.h>
#include <trace/events/block.h>
#include "nvme.h"
static bool multipath = true;
module_param(multipath, bool, 0444);
MODULE_PARM_DESC(multipath,
"turn on native support for multiple controllers per subsystem");
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);
}
/*
* If multipathing is enabled we need to always use the subsystem instance
* number for numbering our devices to avoid conflicts between subsystems that
* have multiple controllers and thus use the multipath-aware subsystem node
* and those that have a single controller and use the controller node
* directly.
*/
void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
struct nvme_ctrl *ctrl, int *flags)
{
if (!multipath) {
sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
} else if (ns->head->disk) {
sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
ctrl->instance, ns->head->instance);
*flags = GENHD_FL_HIDDEN;
} else {
sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
ns->head->instance);
}
}
void nvme_failover_req(struct request *req)
{
struct nvme_ns *ns = req->q->queuedata;
u16 status = nvme_req(req)->status & 0x7ff;
unsigned long flags;
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);
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)
kblockd_schedule_work(&ns->head->requeue_work);
}
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;
mutex_lock(&ctrl->scan_lock);
down_read(&ctrl->namespaces_rwsem);
list_for_each_entry(ns, &ctrl->namespaces, list)
if (nvme_mpath_clear_current_path(ns))
kblockd_schedule_work(&ns->head->requeue_work);
up_read(&ctrl->namespaces_rwsem);
mutex_unlock(&ctrl->scan_lock);
}
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_REMOVING, &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 != 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) {
switch (ns->ctrl->state) {
case NVME_CTRL_LIVE:
case NVME_CTRL_RESETTING:
case NVME_CTRL_CONNECTING:
/* fallthru */
return true;
default:
break;
}
}
return false;
}
blk_qc_t nvme_ns_head_submit_bio(struct bio *bio)
{
struct nvme_ns_head *head = bio->bi_disk->private_data;
struct device *dev = disk_to_dev(head->disk);
struct nvme_ns *ns;
blk_qc_t ret = BLK_QC_T_NONE;
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.
*/
blk_queue_split(&bio);
srcu_idx = srcu_read_lock(&head->srcu);
ns = nvme_find_path(head);
if (likely(ns)) {
bio->bi_disk = ns->disk;
bio->bi_opf |= REQ_NVME_MPATH;
trace_block_bio_remap(bio->bi_disk->queue, bio,
disk_devt(ns->head->disk),
bio->bi_iter.bi_sector);
ret = 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->bi_status = BLK_STS_IOERR;
bio_endio(bio);
}
srcu_read_unlock(&head->srcu, srcu_idx);
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;
/*
* Reset disk to the mpath node and resubmit to select a new
* path.
*/
bio->bi_disk = head->disk;
submit_bio_noacct(bio);
}
}
int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
{
struct request_queue *q;
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 data could
* change after a rescan.
*/
if (!(ctrl->subsys->cmic & NVME_CTRL_CMIC_MULTI_CTRL) || !multipath)
return 0;
q = blk_alloc_queue(ctrl->numa_node);
if (!q)
goto out;
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)
vwc = true;
blk_queue_write_cache(q, vwc, vwc);
head->disk = alloc_disk(0);
if (!head->disk)
goto out_cleanup_queue;
head->disk->fops = &nvme_ns_head_ops;
head->disk->private_data = head;
head->disk->queue = q;
head->disk->flags = GENHD_FL_EXT_DEVT;
sprintf(head->disk->disk_name, "nvme%dn%d",
ctrl->subsys->instance, head->instance);
return 0;
out_cleanup_queue:
blk_cleanup_queue(q);
out:
return -ENOMEM;
}
static void nvme_mpath_set_live(struct nvme_ns *ns)
{
struct nvme_ns_head *head = ns->head;
if (!head->disk)
return;
if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags))
device_add_disk(&head->subsys->dev, head->disk,
nvme_ns_id_attr_groups);
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 = nr_nsids * sizeof(__le32);
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);
if (nvme_state_is_live(ns->ana_state))
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 = 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;
}
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);
}
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 const char *nvme_iopolicy_names[] = {
[NVME_IOPOLICY_NUMA] = "numa",
[NVME_IOPOLICY_RR] = "round-robin",
};
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 sprintf(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 sprintf(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 sprintf(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, struct nvme_id_ns *id)
{
if (nvme_ctrl_use_ana(ns->ctrl)) {
struct nvme_ana_group_desc desc = {
.grpid = id->anagrpid,
.state = 0,
};
mutex_lock(&ns->ctrl->ana_lock);
ns->ana_grpid = le32_to_cpu(id->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 {
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);
}
void nvme_mpath_remove_disk(struct nvme_ns_head *head)
{
if (!head->disk)
return;
if (head->disk->flags & GENHD_FL_UP)
del_gendisk(head->disk);
blk_set_queue_dying(head->disk->queue);
/* make sure all pending bios are cleaned up */
kblockd_schedule_work(&head->requeue_work);
flush_work(&head->requeue_work);
blk_cleanup_queue(head->disk->queue);
if (!test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
/*
* if device_add_disk wasn't called, prevent
* disk release to put a bogus reference on the
* request queue
*/
head->disk->queue = NULL;
}
put_disk(head->disk);
}
int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
{
int error;
/* check if multipath is enabled and we have the capability */
if (!multipath || !ctrl->subsys ||
!(ctrl->subsys->cmic & NVME_CTRL_CMIC_ANA))
return 0;
ctrl->anacap = id->anacap;
ctrl->anatt = id->anatt;
ctrl->nanagrpid = le32_to_cpu(id->nanagrpid);
ctrl->anagrpmax = le32_to_cpu(id->anagrpmax);
mutex_init(&ctrl->ana_lock);
timer_setup(&ctrl->anatt_timer, nvme_anatt_timeout, 0);
ctrl->ana_log_size = sizeof(struct nvme_ana_rsp_hdr) +
ctrl->nanagrpid * sizeof(struct nvme_ana_group_desc);
ctrl->ana_log_size += ctrl->max_namespaces * sizeof(__le32);
if (ctrl->ana_log_size > ctrl->max_hw_sectors << SECTOR_SHIFT) {
dev_err(ctrl->device,
"ANA log page size (%zd) larger than MDTS (%d).\n",
ctrl->ana_log_size,
ctrl->max_hw_sectors << SECTOR_SHIFT);
dev_err(ctrl->device, "disabling ANA support.\n");
return 0;
}
INIT_WORK(&ctrl->ana_work, nvme_ana_work);
kfree(ctrl->ana_log_buf);
ctrl->ana_log_buf = kmalloc(ctrl->ana_log_size, GFP_KERNEL);
if (!ctrl->ana_log_buf) {
error = -ENOMEM;
goto out;
}
error = nvme_read_ana_log(ctrl);
if (error)
goto out_free_ana_log_buf;
return 0;
out_free_ana_log_buf:
kfree(ctrl->ana_log_buf);
ctrl->ana_log_buf = NULL;
out:
return error;
}
void nvme_mpath_uninit(struct nvme_ctrl *ctrl)
{
kfree(ctrl->ana_log_buf);
ctrl->ana_log_buf = NULL;
}