From: Yu Kuai <yukuai3@xxxxxxxxxx>
In some context it's safe to access md_thread directly without
protection, this patch add a helper to do that. There are no functional
changes, prepare to protect md_thread with rcu.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/md-bitmap.c | 7 ++++---
drivers/md/md.c | 4 +++-
drivers/md/md.h | 6 ++++++
drivers/md/raid10.c | 2 +-
drivers/md/raid5-cache.c | 7 ++++---
5 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index e7cc6ba1b657..f670c72d97be 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -1246,7 +1246,7 @@ void md_bitmap_daemon_work(struct mddev *mddev)
bitmap->daemon_lastrun = jiffies;
if (bitmap->allclean) {
- mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
+ get_md_thread(mddev->thread)->timeout = MAX_SCHEDULE_TIMEOUT;
goto done;
}
bitmap->allclean = 1;
@@ -1343,7 +1343,7 @@ void md_bitmap_daemon_work(struct mddev *mddev)
done:
if (bitmap->allclean == 0)
- mddev->thread->timeout =
+ get_md_thread(mddev->thread)->timeout =
mddev->bitmap_info.daemon_sleep;
mutex_unlock(&mddev->bitmap_info.mutex);
}
@@ -1941,7 +1941,8 @@ int md_bitmap_load(struct mddev *mddev)
/* Kick recovery in case any bits were set */
set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
- mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
+ get_md_thread(mddev->thread)->timeout =
+ mddev->bitmap_info.daemon_sleep;
md_wakeup_thread(mddev->thread);
md_bitmap_update_sb(bitmap);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 139c7b0202e3..d5a29ccb24ec 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -458,7 +458,9 @@ static void md_submit_bio(struct bio *bio)
*/
void mddev_suspend(struct mddev *mddev)
{
- WARN_ON_ONCE(mddev->thread && current == mddev->thread->tsk);
+ struct md_thread *thread = get_md_thread(mddev->thread);
+
+ WARN_ON_ONCE(thread && current == thread->tsk);
lockdep_assert_held(&mddev->reconfig_mutex);
if (mddev->suspended++)
return;
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 344e055e4d0f..5acdd704a922 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -718,6 +718,12 @@ struct md_io_acct {
#define THREAD_WAKEUP 0
+/* caller need to make sured returned md_thread won't be freed */
+static inline struct md_thread *get_md_thread(struct md_thread *t)
+{
+ return t;
+}
+
static inline void safe_put_page(struct page *p)
{
if (p) put_page(p);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 0171ba4f19b0..fc8d07fb1c7d 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -996,7 +996,7 @@ static bool stop_waiting_barrier(struct r10conf *conf)
return true;
/* move on if recovery thread is blocked by us */
- if (conf->mddev->thread->tsk == current &&
+ if (get_md_thread(conf->mddev->thread)->tsk == current &&
test_bit(MD_RECOVERY_RUNNING, &conf->mddev->recovery) &&
conf->nr_queued > 0)
return true;
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 0464d4d551fc..7e45df3e093f 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -1582,11 +1582,11 @@ void r5l_quiesce(struct r5l_log *log, int quiesce)
/* make sure r5l_write_super_and_discard_space exits */
mddev = log->rdev->mddev;
wake_up(&mddev->sb_wait);
- kthread_park(log->reclaim_thread->tsk);
+ kthread_park(get_md_thread(log->reclaim_thread)->tsk);
r5l_wake_reclaim(log, MaxSector);
r5l_do_reclaim(log);
} else
- kthread_unpark(log->reclaim_thread->tsk);
+ kthread_unpark(get_md_thread(log->reclaim_thread)->tsk);
}
bool r5l_log_disk_error(struct r5conf *conf)
@@ -3124,7 +3124,8 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
if (md_register_thread(&log->reclaim_thread, r5l_reclaim_thread,
log->rdev->mddev, "reclaim"))
goto reclaim_thread;
- log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
+ get_md_thread(log->reclaim_thread)->timeout =
+ R5C_RECLAIM_WAKEUP_INTERVAL;
init_waitqueue_head(&log->iounit_wait);
--
2.39.2
