Merge branch 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-6.3/block

Pull MD updates from Song:

"Non-urgent fixes:
   md: don't update recovery_cp when curr_resync is ACTIVE
   md: Free writes_pending in md_stop

 Performance optimization:
   md: Change active_io to percpu"

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md: use MD_RESYNC_* whenever possible
  md: Free writes_pending in md_stop
  md: Change active_io to percpu
  md: Factor out is_md_suspended helper
  md: don't update recovery_cp when curr_resync is ACTIVE

2 files changed, 37 insertions, 24 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 02b0240e7c71..1961105712b7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -380,6 +380,10 @@ EXPORT_SYMBOL_GPL(md_new_event);
 static LIST_HEAD(all_mddevs);
 static DEFINE_SPINLOCK(all_mddevs_lock);
 
+static bool is_md_suspended(struct mddev *mddev)
+{
+	return percpu_ref_is_dying(&mddev->active_io);
+}
 /* Rather than calling directly into the personality make_request function,
  * IO requests come here first so that we can check if the device is
  * being suspended pending a reconfiguration.
@@ -389,7 +393,7 @@ static DEFINE_SPINLOCK(all_mddevs_lock);
  */
 static bool is_suspended(struct mddev *mddev, struct bio *bio)
 {
-	if (mddev->suspended)
+	if (is_md_suspended(mddev))
 		return true;
 	if (bio_data_dir(bio) != WRITE)
 		return false;
@@ -405,12 +409,10 @@ static bool is_suspended(struct mddev *mddev, struct bio *bio)
 void md_handle_request(struct mddev *mddev, struct bio *bio)
 {
 check_suspended:
-	rcu_read_lock();
 	if (is_suspended(mddev, bio)) {
 		DEFINE_WAIT(__wait);
 		/* Bail out if REQ_NOWAIT is set for the bio */
 		if (bio->bi_opf & REQ_NOWAIT) {
-			rcu_read_unlock();
 			bio_wouldblock_error(bio);
 			return;
 		}
@@ -419,23 +421,19 @@ check_suspended:
 					TASK_UNINTERRUPTIBLE);
 			if (!is_suspended(mddev, bio))
 				break;
-			rcu_read_unlock();
 			schedule();
-			rcu_read_lock();
 		}
 		finish_wait(&mddev->sb_wait, &__wait);
 	}
-	atomic_inc(&mddev->active_io);
-	rcu_read_unlock();
+	if (!percpu_ref_tryget_live(&mddev->active_io))
+		goto check_suspended;
 
 	if (!mddev->pers->make_request(mddev, bio)) {
-		atomic_dec(&mddev->active_io);
-		wake_up(&mddev->sb_wait);
+		percpu_ref_put(&mddev->active_io);
 		goto check_suspended;
 	}
 
-	if (atomic_dec_and_test(&mddev->active_io) && mddev->suspended)
-		wake_up(&mddev->sb_wait);
+	percpu_ref_put(&mddev->active_io);
 }
 EXPORT_SYMBOL(md_handle_request);
 
@@ -483,11 +481,10 @@ void mddev_suspend(struct mddev *mddev)
 	lockdep_assert_held(&mddev->reconfig_mutex);
 	if (mddev->suspended++)
 		return;
-	synchronize_rcu();
 	wake_up(&mddev->sb_wait);
 	set_bit(MD_ALLOW_SB_UPDATE, &mddev->flags);
-	smp_mb__after_atomic();
-	wait_event(mddev->sb_wait, atomic_read(&mddev->active_io) == 0);
+	percpu_ref_kill(&mddev->active_io);
+	wait_event(mddev->sb_wait, percpu_ref_is_zero(&mddev->active_io));
 	mddev->pers->quiesce(mddev, 1);
 	clear_bit_unlock(MD_ALLOW_SB_UPDATE, &mddev->flags);
 	wait_event(mddev->sb_wait, !test_bit(MD_UPDATING_SB, &mddev->flags));
@@ -505,6 +502,7 @@ void mddev_resume(struct mddev *mddev)
 	lockdep_assert_held(&mddev->reconfig_mutex);
 	if (--mddev->suspended)
 		return;
+	percpu_ref_resurrect(&mddev->active_io);
 	wake_up(&mddev->sb_wait);
 	mddev->pers->quiesce(mddev, 0);
 
@@ -683,7 +681,6 @@ void mddev_init(struct mddev *mddev)
 	timer_setup(&mddev->safemode_timer, md_safemode_timeout, 0);
 	atomic_set(&mddev->active, 1);
 	atomic_set(&mddev->openers, 0);
-	atomic_set(&mddev->active_io, 0);
 	spin_lock_init(&mddev->lock);
 	atomic_set(&mddev->flush_pending, 0);
 	init_waitqueue_head(&mddev->sb_wait);
@@ -5760,6 +5757,12 @@ static void md_safemode_timeout(struct timer_list *t)
 }
 
 static int start_dirty_degraded;
+static void active_io_release(struct percpu_ref *ref)
+{
+	struct mddev *mddev = container_of(ref, struct mddev, active_io);
+
+	wake_up(&mddev->sb_wait);
+}
 
 int md_run(struct mddev *mddev)
 {
@@ -5840,10 +5843,15 @@ int md_run(struct mddev *mddev)
 		nowait = nowait && bdev_nowait(rdev->bdev);
 	}
 
+	err = percpu_ref_init(&mddev->active_io, active_io_release,
+				PERCPU_REF_ALLOW_REINIT, GFP_KERNEL);
+	if (err)
+		return err;
+
 	if (!bioset_initialized(&mddev->bio_set)) {
 		err = bioset_init(&mddev->bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
 		if (err)
-			return err;
+			goto exit_active_io;
 	}
 	if (!bioset_initialized(&mddev->sync_set)) {
 		err = bioset_init(&mddev->sync_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
@@ -6031,6 +6039,8 @@ abort:
 	bioset_exit(&mddev->sync_set);
 exit_bio_set:
 	bioset_exit(&mddev->bio_set);
+exit_active_io:
+	percpu_ref_exit(&mddev->active_io);
 	return err;
 }
 EXPORT_SYMBOL_GPL(md_run);
@@ -6156,7 +6166,7 @@ static void md_clean(struct mddev *mddev)
 	mddev->new_level = LEVEL_NONE;
 	mddev->new_layout = 0;
 	mddev->new_chunk_sectors = 0;
-	mddev->curr_resync = 0;
+	mddev->curr_resync = MD_RESYNC_NONE;
 	atomic64_set(&mddev->resync_mismatches, 0);
 	mddev->suspend_lo = mddev->suspend_hi = 0;
 	mddev->sync_speed_min = mddev->sync_speed_max = 0;
@@ -6219,7 +6229,7 @@ EXPORT_SYMBOL_GPL(md_stop_writes);
 static void mddev_detach(struct mddev *mddev)
 {
 	md_bitmap_wait_behind_writes(mddev);
-	if (mddev->pers && mddev->pers->quiesce && !mddev->suspended) {
+	if (mddev->pers && mddev->pers->quiesce && !is_md_suspended(mddev)) {
 		mddev->pers->quiesce(mddev, 1);
 		mddev->pers->quiesce(mddev, 0);
 	}
@@ -6255,6 +6265,8 @@ void md_stop(struct mddev *mddev)
 	 */
 	__md_stop_writes(mddev);
 	__md_stop(mddev);
+	percpu_ref_exit(&mddev->writes_pending);
+	percpu_ref_exit(&mddev->active_io);
 	bioset_exit(&mddev->bio_set);
 	bioset_exit(&mddev->sync_set);
 }
@@ -7828,6 +7840,7 @@ static void md_free_disk(struct gendisk *disk)
 	struct mddev *mddev = disk->private_data;
 
 	percpu_ref_exit(&mddev->writes_pending);
+	percpu_ref_exit(&mddev->active_io);
 	bioset_exit(&mddev->bio_set);
 	bioset_exit(&mddev->sync_set);
 
@@ -8531,7 +8544,7 @@ bool md_write_start(struct mddev *mddev, struct bio *bi)
 		return true;
 	wait_event(mddev->sb_wait,
 		   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) ||
-		   mddev->suspended);
+		   is_md_suspended(mddev));
 	if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) {
 		percpu_ref_put(&mddev->writes_pending);
 		return false;
@@ -8883,7 +8896,7 @@ void md_do_sync(struct md_thread *thread)
 	atomic_set(&mddev->recovery_active, 0);
 	last_check = 0;
 
-	if (j>2) {
+	if (j >= MD_RESYNC_ACTIVE) {
 		pr_debug("md: resuming %s of %s from checkpoint.\n",
 			 desc, mdname(mddev));
 		mddev->curr_resync = j;
@@ -8955,7 +8968,7 @@ void md_do_sync(struct md_thread *thread)
 		if (j > max_sectors)
 			/* when skipping, extra large numbers can be returned. */
 			j = max_sectors;
-		if (j > 2)
+		if (j >= MD_RESYNC_ACTIVE)
 			mddev->curr_resync = j;
 		mddev->curr_mark_cnt = io_sectors;
 		if (last_check == 0)
@@ -9030,7 +9043,7 @@ void md_do_sync(struct md_thread *thread)
 	mddev->pers->sync_request(mddev, max_sectors, &skipped);
 
 	if (!test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
-	    mddev->curr_resync >= MD_RESYNC_ACTIVE) {
+	    mddev->curr_resync > MD_RESYNC_ACTIVE) {
 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
 				if (mddev->curr_resync >= mddev->recovery_cp) {
@@ -9259,7 +9272,7 @@ void md_check_recovery(struct mddev *mddev)
 		wake_up(&mddev->sb_wait);
 	}
 
-	if (mddev->suspended)
+	if (is_md_suspended(mddev))
 		return;
 
 	if (mddev->bitmap)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 554a9026669a..6335cb86e52e 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -315,7 +315,7 @@ struct mddev {
 	unsigned long			sb_flags;
 
 	int				suspended;
-	atomic_t			active_io;
+	struct percpu_ref		active_io;
 	int				ro;
 	int				sysfs_active; /* set when sysfs deletes
 						       * are happening, so run/