md: protect md_thread with rcu

Currently, there are many places that md_thread can be accessed without
protection, following are known scenarios that can cause
null-ptr-dereference or uaf:

1) sync_thread that is allocated and started from md_start_sync()
2) mddev->thread can be accessed directly from timeout_store() and
   md_bitmap_daemon_work()
3) md_unregister_thread() from action_store().

Currently, a global spinlock 'pers_lock' is borrowed to protect
'mddev->thread' in some places, this problem can be fixed likewise,
however, use a global lock for all the cases is not good.

Fix this problem by protecting all md_thread with rcu.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230523021017.3048783-6-yukuai1@huaweicloud.com
This commit is contained in:
Yu Kuai 2023-05-23 10:10:17 +08:00 committed by Song Liu
parent 4eeb6535cd
commit 4469315439
12 changed files with 97 additions and 81 deletions

View File

@ -1237,13 +1237,19 @@ static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
static void mddev_set_timeout(struct mddev *mddev, unsigned long timeout, static void mddev_set_timeout(struct mddev *mddev, unsigned long timeout,
bool force) bool force)
{ {
struct md_thread *thread = mddev->thread; struct md_thread *thread;
rcu_read_lock();
thread = rcu_dereference(mddev->thread);
if (!thread) if (!thread)
return; goto out;
if (force || thread->timeout < MAX_SCHEDULE_TIMEOUT) if (force || thread->timeout < MAX_SCHEDULE_TIMEOUT)
thread->timeout = timeout; thread->timeout = timeout;
out:
rcu_read_unlock();
} }
/* /*

View File

@ -75,14 +75,14 @@ struct md_cluster_info {
sector_t suspend_hi; sector_t suspend_hi;
int suspend_from; /* the slot which broadcast suspend_lo/hi */ int suspend_from; /* the slot which broadcast suspend_lo/hi */
struct md_thread *recovery_thread; struct md_thread __rcu *recovery_thread;
unsigned long recovery_map; unsigned long recovery_map;
/* communication loc resources */ /* communication loc resources */
struct dlm_lock_resource *ack_lockres; struct dlm_lock_resource *ack_lockres;
struct dlm_lock_resource *message_lockres; struct dlm_lock_resource *message_lockres;
struct dlm_lock_resource *token_lockres; struct dlm_lock_resource *token_lockres;
struct dlm_lock_resource *no_new_dev_lockres; struct dlm_lock_resource *no_new_dev_lockres;
struct md_thread *recv_thread; struct md_thread __rcu *recv_thread;
struct completion newdisk_completion; struct completion newdisk_completion;
wait_queue_head_t wait; wait_queue_head_t wait;
unsigned long state; unsigned long state;
@ -362,8 +362,8 @@ static void __recover_slot(struct mddev *mddev, int slot)
set_bit(slot, &cinfo->recovery_map); set_bit(slot, &cinfo->recovery_map);
if (!cinfo->recovery_thread) { if (!cinfo->recovery_thread) {
cinfo->recovery_thread = md_register_thread(recover_bitmaps, rcu_assign_pointer(cinfo->recovery_thread,
mddev, "recover"); md_register_thread(recover_bitmaps, mddev, "recover"));
if (!cinfo->recovery_thread) { if (!cinfo->recovery_thread) {
pr_warn("md-cluster: Could not create recovery thread\n"); pr_warn("md-cluster: Could not create recovery thread\n");
return; return;
@ -526,11 +526,15 @@ static void process_add_new_disk(struct mddev *mddev, struct cluster_msg *cmsg)
static void process_metadata_update(struct mddev *mddev, struct cluster_msg *msg) static void process_metadata_update(struct mddev *mddev, struct cluster_msg *msg)
{ {
int got_lock = 0; int got_lock = 0;
struct md_thread *thread;
struct md_cluster_info *cinfo = mddev->cluster_info; struct md_cluster_info *cinfo = mddev->cluster_info;
mddev->good_device_nr = le32_to_cpu(msg->raid_slot); mddev->good_device_nr = le32_to_cpu(msg->raid_slot);
dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR); dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
wait_event(mddev->thread->wqueue,
/* daemaon thread must exist */
thread = rcu_dereference_protected(mddev->thread, true);
wait_event(thread->wqueue,
(got_lock = mddev_trylock(mddev)) || (got_lock = mddev_trylock(mddev)) ||
test_bit(MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD, &cinfo->state)); test_bit(MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD, &cinfo->state));
md_reload_sb(mddev, mddev->good_device_nr); md_reload_sb(mddev, mddev->good_device_nr);
@ -889,7 +893,8 @@ static int join(struct mddev *mddev, int nodes)
} }
/* Initiate the communication resources */ /* Initiate the communication resources */
ret = -ENOMEM; ret = -ENOMEM;
cinfo->recv_thread = md_register_thread(recv_daemon, mddev, "cluster_recv"); rcu_assign_pointer(cinfo->recv_thread,
md_register_thread(recv_daemon, mddev, "cluster_recv"));
if (!cinfo->recv_thread) { if (!cinfo->recv_thread) {
pr_err("md-cluster: cannot allocate memory for recv_thread!\n"); pr_err("md-cluster: cannot allocate memory for recv_thread!\n");
goto err; goto err;

View File

@ -400,8 +400,8 @@ static int multipath_run (struct mddev *mddev)
if (ret) if (ret)
goto out_free_conf; goto out_free_conf;
mddev->thread = md_register_thread(multipathd, mddev, rcu_assign_pointer(mddev->thread,
"multipath"); md_register_thread(multipathd, mddev, "multipath"));
if (!mddev->thread) if (!mddev->thread)
goto out_free_conf; goto out_free_conf;

View File

@ -70,11 +70,7 @@
#include "md-bitmap.h" #include "md-bitmap.h"
#include "md-cluster.h" #include "md-cluster.h"
/* pers_list is a list of registered personalities protected /* pers_list is a list of registered personalities protected by pers_lock. */
* by pers_lock.
* pers_lock does extra service to protect accesses to
* mddev->thread when the mutex cannot be held.
*/
static LIST_HEAD(pers_list); static LIST_HEAD(pers_list);
static DEFINE_SPINLOCK(pers_lock); static DEFINE_SPINLOCK(pers_lock);
@ -92,7 +88,7 @@ static int remove_and_add_spares(struct mddev *mddev,
struct md_rdev *this); struct md_rdev *this);
static void mddev_detach(struct mddev *mddev); static void mddev_detach(struct mddev *mddev);
static void export_rdev(struct md_rdev *rdev, struct mddev *mddev); static void export_rdev(struct md_rdev *rdev, struct mddev *mddev);
static void md_wakeup_thread_directly(struct md_thread *thread); static void md_wakeup_thread_directly(struct md_thread __rcu *thread);
/* /*
* Default number of read corrections we'll attempt on an rdev * Default number of read corrections we'll attempt on an rdev
@ -442,8 +438,10 @@ static void md_submit_bio(struct bio *bio)
*/ */
void mddev_suspend(struct mddev *mddev) void mddev_suspend(struct mddev *mddev)
{ {
WARN_ON_ONCE(mddev->thread && current == mddev->thread->tsk); struct md_thread *thread = rcu_dereference_protected(mddev->thread,
lockdep_assert_held(&mddev->reconfig_mutex); lockdep_is_held(&mddev->reconfig_mutex));
WARN_ON_ONCE(thread && current == thread->tsk);
if (mddev->suspended++) if (mddev->suspended++)
return; return;
wake_up(&mddev->sb_wait); wake_up(&mddev->sb_wait);
@ -811,13 +809,8 @@ void mddev_unlock(struct mddev *mddev)
md_free_rdev(mddev); md_free_rdev(mddev);
/* As we've dropped the mutex we need a spinlock to
* make sure the thread doesn't disappear
*/
spin_lock(&pers_lock);
md_wakeup_thread(mddev->thread); md_wakeup_thread(mddev->thread);
wake_up(&mddev->sb_wait); wake_up(&mddev->sb_wait);
spin_unlock(&pers_lock);
} }
EXPORT_SYMBOL_GPL(mddev_unlock); EXPORT_SYMBOL_GPL(mddev_unlock);
@ -7903,19 +7896,29 @@ static int md_thread(void *arg)
return 0; return 0;
} }
static void md_wakeup_thread_directly(struct md_thread *thread) static void md_wakeup_thread_directly(struct md_thread __rcu *thread)
{ {
if (thread) struct md_thread *t;
wake_up_process(thread->tsk);
rcu_read_lock();
t = rcu_dereference(thread);
if (t)
wake_up_process(t->tsk);
rcu_read_unlock();
} }
void md_wakeup_thread(struct md_thread *thread) void md_wakeup_thread(struct md_thread __rcu *thread)
{ {
if (thread) { struct md_thread *t;
pr_debug("md: waking up MD thread %s.\n", thread->tsk->comm);
set_bit(THREAD_WAKEUP, &thread->flags); rcu_read_lock();
wake_up(&thread->wqueue); t = rcu_dereference(thread);
if (t) {
pr_debug("md: waking up MD thread %s.\n", t->tsk->comm);
set_bit(THREAD_WAKEUP, &t->flags);
wake_up(&t->wqueue);
} }
rcu_read_unlock();
} }
EXPORT_SYMBOL(md_wakeup_thread); EXPORT_SYMBOL(md_wakeup_thread);
@ -7945,22 +7948,15 @@ struct md_thread *md_register_thread(void (*run) (struct md_thread *),
} }
EXPORT_SYMBOL(md_register_thread); EXPORT_SYMBOL(md_register_thread);
void md_unregister_thread(struct md_thread **threadp) void md_unregister_thread(struct md_thread __rcu **threadp)
{ {
struct md_thread *thread; struct md_thread *thread = rcu_dereference_protected(*threadp, true);
/* if (!thread)
* Locking ensures that mddev_unlock does not wake_up a
* non-existent thread
*/
spin_lock(&pers_lock);
thread = *threadp;
if (!thread) {
spin_unlock(&pers_lock);
return; return;
}
*threadp = NULL; rcu_assign_pointer(*threadp, NULL);
spin_unlock(&pers_lock); synchronize_rcu();
pr_debug("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk)); pr_debug("interrupting MD-thread pid %d\n", task_pid_nr(thread->tsk));
kthread_stop(thread->tsk); kthread_stop(thread->tsk);
@ -9226,9 +9222,8 @@ static void md_start_sync(struct work_struct *ws)
{ {
struct mddev *mddev = container_of(ws, struct mddev, del_work); struct mddev *mddev = container_of(ws, struct mddev, del_work);
mddev->sync_thread = md_register_thread(md_do_sync, rcu_assign_pointer(mddev->sync_thread,
mddev, md_register_thread(md_do_sync, mddev, "resync"));
"resync");
if (!mddev->sync_thread) { if (!mddev->sync_thread) {
pr_warn("%s: could not start resync thread...\n", pr_warn("%s: could not start resync thread...\n",
mdname(mddev)); mdname(mddev));

View File

@ -365,8 +365,8 @@ struct mddev {
int new_chunk_sectors; int new_chunk_sectors;
int reshape_backwards; int reshape_backwards;
struct md_thread *thread; /* management thread */ struct md_thread __rcu *thread; /* management thread */
struct md_thread *sync_thread; /* doing resync or reconstruct */ struct md_thread __rcu *sync_thread; /* doing resync or reconstruct */
/* 'last_sync_action' is initialized to "none". It is set when a /* 'last_sync_action' is initialized to "none". It is set when a
* sync operation (i.e "data-check", "requested-resync", "resync", * sync operation (i.e "data-check", "requested-resync", "resync",
@ -758,8 +758,8 @@ extern struct md_thread *md_register_thread(
void (*run)(struct md_thread *thread), void (*run)(struct md_thread *thread),
struct mddev *mddev, struct mddev *mddev,
const char *name); const char *name);
extern void md_unregister_thread(struct md_thread **threadp); extern void md_unregister_thread(struct md_thread __rcu **threadp);
extern void md_wakeup_thread(struct md_thread *thread); extern void md_wakeup_thread(struct md_thread __rcu *thread);
extern void md_check_recovery(struct mddev *mddev); extern void md_check_recovery(struct mddev *mddev);
extern void md_reap_sync_thread(struct mddev *mddev); extern void md_reap_sync_thread(struct mddev *mddev);
extern int mddev_init_writes_pending(struct mddev *mddev); extern int mddev_init_writes_pending(struct mddev *mddev);

View File

@ -3087,7 +3087,8 @@ static struct r1conf *setup_conf(struct mddev *mddev)
} }
err = -ENOMEM; err = -ENOMEM;
conf->thread = md_register_thread(raid1d, mddev, "raid1"); rcu_assign_pointer(conf->thread,
md_register_thread(raid1d, mddev, "raid1"));
if (!conf->thread) if (!conf->thread)
goto abort; goto abort;
@ -3180,8 +3181,8 @@ static int raid1_run(struct mddev *mddev)
/* /*
* Ok, everything is just fine now * Ok, everything is just fine now
*/ */
mddev->thread = conf->thread; rcu_assign_pointer(mddev->thread, conf->thread);
conf->thread = NULL; rcu_assign_pointer(conf->thread, NULL);
mddev->private = conf; mddev->private = conf;
set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags); set_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);

View File

@ -130,7 +130,7 @@ struct r1conf {
/* When taking over an array from a different personality, we store /* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array. * the new thread here until we fully activate the array.
*/ */
struct md_thread *thread; struct md_thread __rcu *thread;
/* Keep track of cluster resync window to send to other /* Keep track of cluster resync window to send to other
* nodes. * nodes.

View File

@ -982,6 +982,7 @@ static void lower_barrier(struct r10conf *conf)
static bool stop_waiting_barrier(struct r10conf *conf) static bool stop_waiting_barrier(struct r10conf *conf)
{ {
struct bio_list *bio_list = current->bio_list; struct bio_list *bio_list = current->bio_list;
struct md_thread *thread;
/* barrier is dropped */ /* barrier is dropped */
if (!conf->barrier) if (!conf->barrier)
@ -997,12 +998,14 @@ static bool stop_waiting_barrier(struct r10conf *conf)
(!bio_list_empty(&bio_list[0]) || !bio_list_empty(&bio_list[1]))) (!bio_list_empty(&bio_list[0]) || !bio_list_empty(&bio_list[1])))
return true; return true;
/* daemon thread must exist while handling io */
thread = rcu_dereference_protected(conf->mddev->thread, true);
/* /*
* move on if io is issued from raid10d(), nr_pending is not released * move on if io is issued from raid10d(), nr_pending is not released
* from original io(see handle_read_error()). All raise barrier is * from original io(see handle_read_error()). All raise barrier is
* blocked until this io is done. * blocked until this io is done.
*/ */
if (conf->mddev->thread->tsk == current) { if (thread->tsk == current) {
WARN_ON_ONCE(atomic_read(&conf->nr_pending) == 0); WARN_ON_ONCE(atomic_read(&conf->nr_pending) == 0);
return true; return true;
} }
@ -4107,7 +4110,8 @@ static struct r10conf *setup_conf(struct mddev *mddev)
atomic_set(&conf->nr_pending, 0); atomic_set(&conf->nr_pending, 0);
err = -ENOMEM; err = -ENOMEM;
conf->thread = md_register_thread(raid10d, mddev, "raid10"); rcu_assign_pointer(conf->thread,
md_register_thread(raid10d, mddev, "raid10"));
if (!conf->thread) if (!conf->thread)
goto out; goto out;
@ -4152,8 +4156,8 @@ static int raid10_run(struct mddev *mddev)
if (!conf) if (!conf)
goto out; goto out;
mddev->thread = conf->thread; rcu_assign_pointer(mddev->thread, conf->thread);
conf->thread = NULL; rcu_assign_pointer(conf->thread, NULL);
if (mddev_is_clustered(conf->mddev)) { if (mddev_is_clustered(conf->mddev)) {
int fc, fo; int fc, fo;
@ -4296,8 +4300,8 @@ static int raid10_run(struct mddev *mddev)
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev, rcu_assign_pointer(mddev->sync_thread,
"reshape"); md_register_thread(md_do_sync, mddev, "reshape"));
if (!mddev->sync_thread) if (!mddev->sync_thread)
goto out_free_conf; goto out_free_conf;
} }
@ -4698,8 +4702,8 @@ out:
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev, rcu_assign_pointer(mddev->sync_thread,
"reshape"); md_register_thread(md_do_sync, mddev, "reshape"));
if (!mddev->sync_thread) { if (!mddev->sync_thread) {
ret = -EAGAIN; ret = -EAGAIN;
goto abort; goto abort;

View File

@ -100,7 +100,7 @@ struct r10conf {
/* When taking over an array from a different personality, we store /* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array. * the new thread here until we fully activate the array.
*/ */
struct md_thread *thread; struct md_thread __rcu *thread;
/* /*
* Keep track of cluster resync window to send to other nodes. * Keep track of cluster resync window to send to other nodes.

View File

@ -120,7 +120,7 @@ struct r5l_log {
struct bio_set bs; struct bio_set bs;
mempool_t meta_pool; mempool_t meta_pool;
struct md_thread *reclaim_thread; struct md_thread __rcu *reclaim_thread;
unsigned long reclaim_target; /* number of space that need to be unsigned long reclaim_target; /* number of space that need to be
* reclaimed. if it's 0, reclaim spaces * reclaimed. if it's 0, reclaim spaces
* used by io_units which are in * used by io_units which are in
@ -1576,17 +1576,18 @@ void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
void r5l_quiesce(struct r5l_log *log, int quiesce) void r5l_quiesce(struct r5l_log *log, int quiesce)
{ {
struct mddev *mddev; struct mddev *mddev = log->rdev->mddev;
struct md_thread *thread = rcu_dereference_protected(
log->reclaim_thread, lockdep_is_held(&mddev->reconfig_mutex));
if (quiesce) { if (quiesce) {
/* make sure r5l_write_super_and_discard_space exits */ /* make sure r5l_write_super_and_discard_space exits */
mddev = log->rdev->mddev;
wake_up(&mddev->sb_wait); wake_up(&mddev->sb_wait);
kthread_park(log->reclaim_thread->tsk); kthread_park(thread->tsk);
r5l_wake_reclaim(log, MaxSector); r5l_wake_reclaim(log, MaxSector);
r5l_do_reclaim(log); r5l_do_reclaim(log);
} else } else
kthread_unpark(log->reclaim_thread->tsk); kthread_unpark(thread->tsk);
} }
bool r5l_log_disk_error(struct r5conf *conf) bool r5l_log_disk_error(struct r5conf *conf)
@ -3063,6 +3064,7 @@ void r5c_update_on_rdev_error(struct mddev *mddev, struct md_rdev *rdev)
int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
{ {
struct r5l_log *log; struct r5l_log *log;
struct md_thread *thread;
int ret; int ret;
pr_debug("md/raid:%s: using device %pg as journal\n", pr_debug("md/raid:%s: using device %pg as journal\n",
@ -3121,11 +3123,13 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
spin_lock_init(&log->tree_lock); spin_lock_init(&log->tree_lock);
INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN); INIT_RADIX_TREE(&log->big_stripe_tree, GFP_NOWAIT | __GFP_NOWARN);
log->reclaim_thread = md_register_thread(r5l_reclaim_thread, thread = md_register_thread(r5l_reclaim_thread, log->rdev->mddev,
log->rdev->mddev, "reclaim"); "reclaim");
if (!log->reclaim_thread) if (!thread)
goto reclaim_thread; goto reclaim_thread;
log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
rcu_assign_pointer(log->reclaim_thread, thread);
init_waitqueue_head(&log->iounit_wait); init_waitqueue_head(&log->iounit_wait);

View File

@ -7731,7 +7731,8 @@ static struct r5conf *setup_conf(struct mddev *mddev)
} }
sprintf(pers_name, "raid%d", mddev->new_level); sprintf(pers_name, "raid%d", mddev->new_level);
conf->thread = md_register_thread(raid5d, mddev, pers_name); rcu_assign_pointer(conf->thread,
md_register_thread(raid5d, mddev, pers_name));
if (!conf->thread) { if (!conf->thread) {
pr_warn("md/raid:%s: couldn't allocate thread.\n", pr_warn("md/raid:%s: couldn't allocate thread.\n",
mdname(mddev)); mdname(mddev));
@ -7954,8 +7955,8 @@ static int raid5_run(struct mddev *mddev)
} }
conf->min_offset_diff = min_offset_diff; conf->min_offset_diff = min_offset_diff;
mddev->thread = conf->thread; rcu_assign_pointer(mddev->thread, conf->thread);
conf->thread = NULL; rcu_assign_pointer(conf->thread, NULL);
mddev->private = conf; mddev->private = conf;
for (i = 0; i < conf->raid_disks && conf->previous_raid_disks; for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
@ -8052,8 +8053,8 @@ static int raid5_run(struct mddev *mddev)
clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev, rcu_assign_pointer(mddev->sync_thread,
"reshape"); md_register_thread(md_do_sync, mddev, "reshape"));
if (!mddev->sync_thread) if (!mddev->sync_thread)
goto abort; goto abort;
} }
@ -8631,8 +8632,8 @@ static int raid5_start_reshape(struct mddev *mddev)
clear_bit(MD_RECOVERY_DONE, &mddev->recovery); clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
mddev->sync_thread = md_register_thread(md_do_sync, mddev, rcu_assign_pointer(mddev->sync_thread,
"reshape"); md_register_thread(md_do_sync, mddev, "reshape"));
if (!mddev->sync_thread) { if (!mddev->sync_thread) {
mddev->recovery = 0; mddev->recovery = 0;
spin_lock_irq(&conf->device_lock); spin_lock_irq(&conf->device_lock);

View File

@ -679,7 +679,7 @@ struct r5conf {
/* When taking over an array from a different personality, we store /* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array. * the new thread here until we fully activate the array.
*/ */
struct md_thread *thread; struct md_thread __rcu *thread;
struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS];
struct r5worker_group *worker_groups; struct r5worker_group *worker_groups;
int group_cnt; int group_cnt;