md: cleanup pers->prepare_suspend()

pers->prepare_suspend() is not used anymore and can be removed.

Reverts following three commit:

 - commit 431e6125 ("md: export md_is_rdwr() and is_md_suspended()")
 - commit 3e00777d ("md: add a new api prepare_suspend() in
md_personality")
 - commit 868bba54 ("md/raid5: fix a deadlock in the case that reshape
is interrupted")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20231016100240.540474-1-yukuai1@huaweicloud.com

drivers/md/md.c

@@ -91,6 +91,18 @@ static void mddev_detach(struct mddev *mddev);
 static void export_rdev(struct md_rdev *rdev, struct mddev *mddev);
 static void md_wakeup_thread_directly(struct md_thread __rcu *thread);
 
+enum md_ro_state {
+	MD_RDWR,
+	MD_RDONLY,
+	MD_AUTO_READ,
+	MD_MAX_STATE
+};
+
+static bool md_is_rdwr(struct mddev *mddev)
+{
+	return (mddev->ro == MD_RDWR);
+}
+
 /*
  * Default number of read corrections we'll attempt on an rdev
  * before ejecting it from the array. We divide the read error
@@ -333,6 +345,10 @@ 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.
@@ -9144,7 +9160,6 @@ void md_do_sync(struct md_thread *thread)
 	spin_unlock(&mddev->lock);
 
 	wake_up(&resync_wait);
-	wake_up(&mddev->sb_wait);
 	md_wakeup_thread(mddev->thread);
 	return;
 }

drivers/md/md.h

@@ -565,23 +565,6 @@ enum recovery_flags {
 	MD_RESYNCING_REMOTE,	/* remote node is running resync thread */
 };
 
-enum md_ro_state {
-	MD_RDWR,
-	MD_RDONLY,
-	MD_AUTO_READ,
-	MD_MAX_STATE
-};
-
-static inline bool md_is_rdwr(struct mddev *mddev)
-{
-	return (mddev->ro == MD_RDWR);
-}
-
-static inline bool is_md_suspended(struct mddev *mddev)
-{
-	return percpu_ref_is_dying(&mddev->active_io);
-}
-
 static inline int __must_check mddev_lock(struct mddev *mddev)
 {
 	return mutex_lock_interruptible(&mddev->reconfig_mutex);
@@ -641,7 +624,6 @@ struct md_personality
 	int (*start_reshape) (struct mddev *mddev);
 	void (*finish_reshape) (struct mddev *mddev);
 	void (*update_reshape_pos) (struct mddev *mddev);
-	void (*prepare_suspend) (struct mddev *mddev);
 	/* quiesce suspends or resumes internal processing.
 	 * 1 - stop new actions and wait for action io to complete
 	 * 0 - return to normal behaviour

drivers/md/raid5.c

@@ -5953,19 +5953,6 @@ static int add_all_stripe_bios(struct r5conf *conf,
 	return ret;
 }
 
-static bool reshape_inprogress(struct mddev *mddev)
-{
-	return test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
-	       test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
-	       !test_bit(MD_RECOVERY_DONE, &mddev->recovery) &&
-	       !test_bit(MD_RECOVERY_INTR, &mddev->recovery);
-}
-
-static bool reshape_disabled(struct mddev *mddev)
-{
-	return is_md_suspended(mddev) || !md_is_rdwr(mddev);
-}
-
 static enum stripe_result make_stripe_request(struct mddev *mddev,
 		struct r5conf *conf, struct stripe_request_ctx *ctx,
 		sector_t logical_sector, struct bio *bi)
@@ -5997,8 +5984,7 @@ static enum stripe_result make_stripe_request(struct mddev *mddev,
 			if (ahead_of_reshape(mddev, logical_sector,
 					     conf->reshape_safe)) {
 				spin_unlock_irq(&conf->device_lock);
-				ret = STRIPE_SCHEDULE_AND_RETRY;
-				goto out;
+				return STRIPE_SCHEDULE_AND_RETRY;
 			}
 		}
 		spin_unlock_irq(&conf->device_lock);
@@ -6077,15 +6063,6 @@ static enum stripe_result make_stripe_request(struct mddev *mddev,
 
 out_release:
 	raid5_release_stripe(sh);
-out:
-	if (ret == STRIPE_SCHEDULE_AND_RETRY && !reshape_inprogress(mddev) &&
-	    reshape_disabled(mddev)) {
-		bi->bi_status = BLK_STS_IOERR;
-		ret = STRIPE_FAIL;
-		pr_err("md/raid456:%s: io failed across reshape position while reshape can't make progress.\n",
-		       mdname(mddev));
-	}
-
 	return ret;
 }
 
@@ -9027,22 +9004,6 @@ static int raid5_start(struct mddev *mddev)
 	return r5l_start(conf->log);
 }
 
-static void raid5_prepare_suspend(struct mddev *mddev)
-{
-	struct r5conf *conf = mddev->private;
-
-	wait_event(mddev->sb_wait, !reshape_inprogress(mddev) ||
-				    percpu_ref_is_zero(&mddev->active_io));
-	if (percpu_ref_is_zero(&mddev->active_io))
-		return;
-
-	/*
-	 * Reshape is not in progress, and array is suspended, io that is
-	 * waiting for reshpape can never be done.
-	 */
-	wake_up(&conf->wait_for_overlap);
-}
-
 static struct md_personality raid6_personality =
 {
 	.name		= "raid6",
@@ -9063,7 +9024,6 @@ static struct md_personality raid6_personality =
 	.check_reshape	= raid6_check_reshape,
 	.start_reshape  = raid5_start_reshape,
 	.finish_reshape = raid5_finish_reshape,
-	.prepare_suspend = raid5_prepare_suspend,
 	.quiesce	= raid5_quiesce,
 	.takeover	= raid6_takeover,
 	.change_consistency_policy = raid5_change_consistency_policy,
@@ -9088,7 +9048,6 @@ static struct md_personality raid5_personality =
 	.check_reshape	= raid5_check_reshape,
 	.start_reshape  = raid5_start_reshape,
 	.finish_reshape = raid5_finish_reshape,
-	.prepare_suspend = raid5_prepare_suspend,
 	.quiesce	= raid5_quiesce,
 	.takeover	= raid5_takeover,
 	.change_consistency_policy = raid5_change_consistency_policy,
@@ -9114,7 +9073,6 @@ static struct md_personality raid4_personality =
 	.check_reshape	= raid5_check_reshape,
 	.start_reshape  = raid5_start_reshape,
 	.finish_reshape = raid5_finish_reshape,
-	.prepare_suspend = raid5_prepare_suspend,
 	.quiesce	= raid5_quiesce,
 	.takeover	= raid4_takeover,
 	.change_consistency_policy = raid5_change_consistency_policy,