swh:1:snp:3c665ee4f67729f27f2e40193ab88e7298cf0fef
Tip revision: a188339ca5a396acc588e5851ed7e19f66b0ebd9 authored by Linus Torvalds on 19 May 2019, 22:47:09 UTC
Linux 5.2-rc1
Linux 5.2-rc1
Tip revision: a188339
multipath.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2017-2018 Christoph Hellwig.
*/
#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");
inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
{
return multipath && ctrl->subsys && (ctrl->subsys->cmic & (1 << 3));
}
/*
* 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;
unsigned long flags;
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);
switch (status & 0x7ff) {
case NVME_SC_ANA_TRANSITION:
case NVME_SC_ANA_INACCESSIBLE:
case NVME_SC_ANA_PERSISTENT_LOSS:
/*
* If we got back an ANA error we know the controller is alive,
* but not ready to serve this namespaces. The spec suggests
* we should update our general state here, but due to the fact
* that the admin and I/O queues are not serialized that is
* fundamentally racy. So instead just clear the current path,
* mark the the path as pending and kick of a re-read of the ANA
* log page ASAP.
*/
nvme_mpath_clear_current_path(ns);
if (ns->ctrl->ana_log_buf) {
set_bit(NVME_NS_ANA_PENDING, &ns->flags);
queue_work(nvme_wq, &ns->ctrl->ana_work);
}
break;
case NVME_SC_HOST_PATH_ERROR:
/*
* Temporary transport disruption in talking to the controller.
* Try to send on a new path.
*/
nvme_mpath_clear_current_path(ns);
break;
default:
/*
* Reset the controller for any non-ANA error as we don't know
* what caused the error.
*/
nvme_reset_ctrl(ns->ctrl);
break;
}
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",
};
void nvme_mpath_clear_current_path(struct nvme_ns *ns)
{
struct nvme_ns_head *head = ns->head;
int node;
if (!head)
return;
for_each_node(node) {
if (ns == rcu_access_pointer(head->current_path[node]))
rcu_assign_pointer(head->current_path[node], NULL);
}
}
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 (ns->ctrl->state != NVME_CTRL_LIVE ||
test_bit(NVME_NS_ANA_PENDING, &ns->flags))
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, *fallback = NULL;
if (list_is_singular(&head->list))
return old;
for (ns = nvme_next_ns(head, old);
ns != old;
ns = nvme_next_ns(head, ns)) {
if (ns->ctrl->state != NVME_CTRL_LIVE ||
test_bit(NVME_NS_ANA_PENDING, &ns->flags))
continue;
if (ns->ana_state == NVME_ANA_OPTIMIZED) {
found = ns;
goto out;
}
if (ns->ana_state == NVME_ANA_NONOPTIMIZED)
fallback = ns;
}
if (!fallback)
return NULL;
found = fallback;
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 (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR && ns)
ns = nvme_round_robin_path(head, node, ns);
if (unlikely(!ns || !nvme_path_is_optimized(ns)))
ns = __nvme_find_path(head, node);
return ns;
}
static blk_qc_t nvme_ns_head_make_request(struct request_queue *q,
struct bio *bio)
{
struct nvme_ns_head *head = q->queuedata;
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(q, &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 = direct_make_request(bio);
} else if (!list_empty_careful(&head->list)) {
dev_warn_ratelimited(dev, "no path available - 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 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;
generic_make_request(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 & (1 << 1)) || !multipath)
return 0;
q = blk_alloc_queue_node(GFP_KERNEL, ctrl->numa_node);
if (!q)
goto out;
q->queuedata = head;
blk_queue_make_request(q, nvme_ns_head_make_request);
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;
lockdep_assert_held(&ns->head->lock);
if (!head->disk)
return;
if (!(head->disk->flags & GENHD_FL_UP))
device_add_disk(&head->subsys->dev, head->disk,
nvme_ns_id_attr_groups);
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);
}
kblockd_schedule_work(&ns->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 = le32_to_cpu(desc->nnsids);
size_t 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;
if (WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc)))
return -EINVAL;
}
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)
{
mutex_lock(&ns->head->lock);
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);
mutex_unlock(&ns->head->lock);
}
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_write(&ctrl->namespaces_rwsem);
list_for_each_entry(ns, &ctrl->namespaces, list) {
if (ns->head->ns_id != le32_to_cpu(desc->nsids[n]))
continue;
nvme_update_ns_ana_state(desc, ns);
if (++n == nr_nsids)
break;
}
up_write(&ctrl->namespaces_rwsem);
WARN_ON_ONCE(n < nr_nsids);
return 0;
}
static int nvme_read_ana_log(struct nvme_ctrl *ctrl, bool groups_only)
{
u32 nr_change_groups = 0;
int error;
mutex_lock(&ctrl->ana_lock);
error = nvme_get_log(ctrl, NVME_NSID_ALL, NVME_LOG_ANA,
groups_only ? NVME_ANA_LOG_RGO : 0,
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);
nvme_read_ana_log(ctrl, false);
}
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_set_ns_ana_state(struct nvme_ctrl *ctrl,
struct nvme_ana_group_desc *desc, void *data)
{
struct nvme_ns *ns = data;
if (ns->ana_grpid == le32_to_cpu(desc->grpid)) {
nvme_update_ns_ana_state(desc, ns);
return -ENXIO; /* just break out of the loop */
}
return 0;
}
void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id)
{
if (nvme_ctrl_use_ana(ns->ctrl)) {
mutex_lock(&ns->ctrl->ana_lock);
ns->ana_grpid = le32_to_cpu(id->anagrpid);
nvme_parse_ana_log(ns->ctrl, ns, nvme_set_ns_ana_state);
mutex_unlock(&ns->ctrl->ana_lock);
} else {
mutex_lock(&ns->head->lock);
ns->ana_state = NVME_ANA_OPTIMIZED;
nvme_mpath_set_live(ns);
mutex_unlock(&ns->head->lock);
}
}
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);
put_disk(head->disk);
}
int nvme_mpath_init(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
{
int error;
if (!nvme_ctrl_use_ana(ctrl))
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);
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, true);
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;
}