1 files changed, 281 insertions, 207 deletions

diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 496d5f3646a5..4bb6553278c7 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2005-2007 Red Hat GmbH
  *
@@ -12,57 +13,62 @@
 #include <linux/blkdev.h>
 #include <linux/bio.h>
 #include <linux/slab.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
 
 #include <linux/device-mapper.h>
 
 #define DM_MSG_PREFIX "delay"
 
+#define SLEEP_SHIFT 3
+
+struct delay_class {
+	struct dm_dev *dev;
+	sector_t start;
+	unsigned int delay;
+	unsigned int ops;
+};
+
 struct delay_c {
 	struct timer_list delay_timer;
-	struct mutex timer_lock;
+	struct mutex process_bios_lock; /* hold while removing bios to be processed from list */
+	spinlock_t delayed_bios_lock; /* hold on all accesses to delayed_bios list */
+	struct workqueue_struct *kdelayd_wq;
 	struct work_struct flush_expired_bios;
 	struct list_head delayed_bios;
-	atomic_t may_delay;
-	mempool_t *delayed_pool;
-
-	struct dm_dev *dev_read;
-	sector_t start_read;
-	unsigned read_delay;
-	unsigned reads;
-
-	struct dm_dev *dev_write;
-	sector_t start_write;
-	unsigned write_delay;
-	unsigned writes;
+	struct task_struct *worker;
+	unsigned int worker_sleep_us;
+	bool may_delay;
+
+	struct delay_class read;
+	struct delay_class write;
+	struct delay_class flush;
+
+	int argc;
 };
 
 struct dm_delay_info {
 	struct delay_c *context;
+	struct delay_class *class;
 	struct list_head list;
-	struct bio *bio;
 	unsigned long expires;
 };
 
-static DEFINE_MUTEX(delayed_bios_lock);
-
-static struct workqueue_struct *kdelayd_wq;
-static struct kmem_cache *delayed_cache;
-
-static void handle_delayed_timer(unsigned long data)
+static void handle_delayed_timer(struct timer_list *t)
 {
-	struct delay_c *dc = (struct delay_c *)data;
+	struct delay_c *dc = timer_container_of(dc, t, delay_timer);
 
-	queue_work(kdelayd_wq, &dc->flush_expired_bios);
+	queue_work(dc->kdelayd_wq, &dc->flush_expired_bios);
 }
 
 static void queue_timeout(struct delay_c *dc, unsigned long expires)
 {
-	mutex_lock(&dc->timer_lock);
-
-	if (!timer_pending(&dc->delay_timer) || expires < dc->delay_timer.expires)
-		mod_timer(&dc->delay_timer, expires);
+	timer_reduce(&dc->delay_timer, expires);
+}
 
-	mutex_unlock(&dc->timer_lock);
+static inline bool delay_is_fast(struct delay_c *dc)
+{
+	return !!dc->worker;
 }
 
 static void flush_bios(struct bio *bio)
@@ -72,44 +78,74 @@ static void flush_bios(struct bio *bio)
 	while (bio) {
 		n = bio->bi_next;
 		bio->bi_next = NULL;
-		generic_make_request(bio);
+		dm_submit_bio_remap(bio, NULL);
 		bio = n;
 	}
 }
 
-static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
+static void flush_delayed_bios(struct delay_c *dc, bool flush_all)
 {
 	struct dm_delay_info *delayed, *next;
+	struct bio_list flush_bio_list;
+	LIST_HEAD(local_list);
 	unsigned long next_expires = 0;
-	int start_timer = 0;
-	struct bio_list flush_bios = { };
-
-	mutex_lock(&delayed_bios_lock);
-	list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {
+	bool start_timer = false;
+	bio_list_init(&flush_bio_list);
+
+	mutex_lock(&dc->process_bios_lock);
+	spin_lock(&dc->delayed_bios_lock);
+	list_replace_init(&dc->delayed_bios, &local_list);
+	spin_unlock(&dc->delayed_bios_lock);
+	list_for_each_entry_safe(delayed, next, &local_list, list) {
+		cond_resched();
 		if (flush_all || time_after_eq(jiffies, delayed->expires)) {
+			struct bio *bio = dm_bio_from_per_bio_data(delayed,
+						sizeof(struct dm_delay_info));
 			list_del(&delayed->list);
-			bio_list_add(&flush_bios, delayed->bio);
-			if ((bio_data_dir(delayed->bio) == WRITE))
-				delayed->context->writes--;
-			else
-				delayed->context->reads--;
-			mempool_free(delayed, dc->delayed_pool);
+			bio_list_add(&flush_bio_list, bio);
+			delayed->class->ops--;
 			continue;
 		}
 
-		if (!start_timer) {
-			start_timer = 1;
-			next_expires = delayed->expires;
-		} else
-			next_expires = min(next_expires, delayed->expires);
+		if (!delay_is_fast(dc)) {
+			if (!start_timer) {
+				start_timer = true;
+				next_expires = delayed->expires;
+			} else {
+				next_expires = min(next_expires, delayed->expires);
+			}
+		}
 	}
-
-	mutex_unlock(&delayed_bios_lock);
+	spin_lock(&dc->delayed_bios_lock);
+	list_splice(&local_list, &dc->delayed_bios);
+	spin_unlock(&dc->delayed_bios_lock);
+	mutex_unlock(&dc->process_bios_lock);
 
 	if (start_timer)
 		queue_timeout(dc, next_expires);
 
-	return bio_list_get(&flush_bios);
+	flush_bios(bio_list_get(&flush_bio_list));
+}
+
+static int flush_worker_fn(void *data)
+{
+	struct delay_c *dc = data;
+
+	while (!kthread_should_stop()) {
+		flush_delayed_bios(dc, false);
+		spin_lock(&dc->delayed_bios_lock);
+		if (unlikely(list_empty(&dc->delayed_bios))) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			spin_unlock(&dc->delayed_bios_lock);
+			schedule();
+		} else {
+			spin_unlock(&dc->delayed_bios_lock);
+			fsleep(dc->worker_sleep_us);
+			cond_resched();
+		}
+	}
+
+	return 0;
 }
 
 static void flush_expired_bios(struct work_struct *work)
@@ -117,7 +153,56 @@ static void flush_expired_bios(struct work_struct *work)
 	struct delay_c *dc;
 
 	dc = container_of(work, struct delay_c, flush_expired_bios);
-	flush_bios(flush_delayed_bios(dc, 0));
+	flush_delayed_bios(dc, false);
+}
+
+static void delay_dtr(struct dm_target *ti)
+{
+	struct delay_c *dc = ti->private;
+
+	if (dc->kdelayd_wq) {
+		timer_shutdown_sync(&dc->delay_timer);
+		destroy_workqueue(dc->kdelayd_wq);
+	}
+
+	if (dc->read.dev)
+		dm_put_device(ti, dc->read.dev);
+	if (dc->write.dev)
+		dm_put_device(ti, dc->write.dev);
+	if (dc->flush.dev)
+		dm_put_device(ti, dc->flush.dev);
+	if (dc->worker)
+		kthread_stop(dc->worker);
+
+	mutex_destroy(&dc->process_bios_lock);
+
+	kfree(dc);
+}
+
+static int delay_class_ctr(struct dm_target *ti, struct delay_class *c, char **argv)
+{
+	int ret;
+	unsigned long long tmpll;
+	char dummy;
+
+	if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) {
+		ti->error = "Invalid device sector";
+		return -EINVAL;
+	}
+	c->start = tmpll;
+
+	if (sscanf(argv[2], "%u%c", &c->delay, &dummy) != 1) {
+		ti->error = "Invalid delay";
+		return -EINVAL;
+	}
+
+	ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &c->dev);
+	if (ret) {
+		ti->error = "Device lookup failed";
+		return ret;
+	}
+
+	return 0;
 }
 
 /*
@@ -125,193 +210,219 @@ static void flush_expired_bios(struct work_struct *work)
  *    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
  *
  * With separate write parameters, the first set is only used for reads.
+ * Offsets are specified in sectors.
  * Delays are specified in milliseconds.
  */
 static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
 	struct delay_c *dc;
-	unsigned long long tmpll;
-	char dummy;
+	int ret;
+	unsigned int max_delay, min_delay;
 
-	if (argc != 3 && argc != 6) {
-		ti->error = "requires exactly 3 or 6 arguments";
+	if (argc != 3 && argc != 6 && argc != 9) {
+		ti->error = "Requires exactly 3, 6 or 9 arguments";
 		return -EINVAL;
 	}
 
-	dc = kmalloc(sizeof(*dc), GFP_KERNEL);
+	dc = kzalloc(sizeof(*dc), GFP_KERNEL);
 	if (!dc) {
 		ti->error = "Cannot allocate context";
 		return -ENOMEM;
 	}
 
-	dc->reads = dc->writes = 0;
-
-	if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
-		ti->error = "Invalid device sector";
-		goto bad;
-	}
-	dc->start_read = tmpll;
+	ti->private = dc;
+	INIT_LIST_HEAD(&dc->delayed_bios);
+	mutex_init(&dc->process_bios_lock);
+	spin_lock_init(&dc->delayed_bios_lock);
+	dc->may_delay = true;
+	dc->argc = argc;
 
-	if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) {
-		ti->error = "Invalid delay";
+	ret = delay_class_ctr(ti, &dc->read, argv);
+	if (ret)
 		goto bad;
+	min_delay = max_delay = dc->read.delay;
+
+	if (argc == 3) {
+		ret = delay_class_ctr(ti, &dc->write, argv);
+		if (ret)
+			goto bad;
+		ret = delay_class_ctr(ti, &dc->flush, argv);
+		if (ret)
+			goto bad;
+		goto out;
 	}
 
-	if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
-			  &dc->dev_read)) {
-		ti->error = "Device lookup failed";
+	ret = delay_class_ctr(ti, &dc->write, argv + 3);
+	if (ret)
 		goto bad;
-	}
+	max_delay = max(max_delay, dc->write.delay);
+	min_delay = min_not_zero(min_delay, dc->write.delay);
 
-	dc->dev_write = NULL;
-	if (argc == 3)
+	if (argc == 6) {
+		ret = delay_class_ctr(ti, &dc->flush, argv + 3);
+		if (ret)
+			goto bad;
 		goto out;
-
-	if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
-		ti->error = "Invalid write device sector";
-		goto bad_dev_read;
 	}
-	dc->start_write = tmpll;
 
-	if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) {
-		ti->error = "Invalid write delay";
-		goto bad_dev_read;
-	}
-
-	if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table),
-			  &dc->dev_write)) {
-		ti->error = "Write device lookup failed";
-		goto bad_dev_read;
-	}
+	ret = delay_class_ctr(ti, &dc->flush, argv + 6);
+	if (ret)
+		goto bad;
+	max_delay = max(max_delay, dc->flush.delay);
+	min_delay = min_not_zero(min_delay, dc->flush.delay);
 
 out:
-	dc->delayed_pool = mempool_create_slab_pool(128, delayed_cache);
-	if (!dc->delayed_pool) {
-		DMERR("Couldn't create delayed bio pool.");
-		goto bad_dev_write;
+	if (max_delay < 50) {
+		if (min_delay >> SLEEP_SHIFT)
+			dc->worker_sleep_us = 1000;
+		else
+			dc->worker_sleep_us = (min_delay * 1000) >> SLEEP_SHIFT;
+		/*
+		 * In case of small requested delays, use kthread instead of
+		 * timers and workqueue to achieve better latency.
+		 */
+		dc->worker = kthread_run(&flush_worker_fn, dc, "dm-delay-flush-worker");
+		if (IS_ERR(dc->worker)) {
+			ret = PTR_ERR(dc->worker);
+			dc->worker = NULL;
+			goto bad;
+		}
+	} else {
+		timer_setup(&dc->delay_timer, handle_delayed_timer, 0);
+		INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
+		dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
+		if (!dc->kdelayd_wq) {
+			ret = -EINVAL;
+			DMERR("Couldn't start kdelayd");
+			goto bad;
+		}
 	}
 
-	setup_timer(&dc->delay_timer, handle_delayed_timer, (unsigned long)dc);
-
-	INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
-	INIT_LIST_HEAD(&dc->delayed_bios);
-	mutex_init(&dc->timer_lock);
-	atomic_set(&dc->may_delay, 1);
-
 	ti->num_flush_bios = 1;
 	ti->num_discard_bios = 1;
-	ti->private = dc;
+	ti->accounts_remapped_io = true;
+	ti->per_io_data_size = sizeof(struct dm_delay_info);
 	return 0;
 
-bad_dev_write:
-	if (dc->dev_write)
-		dm_put_device(ti, dc->dev_write);
-bad_dev_read:
-	dm_put_device(ti, dc->dev_read);
 bad:
-	kfree(dc);
-	return -EINVAL;
-}
-
-static void delay_dtr(struct dm_target *ti)
-{
-	struct delay_c *dc = ti->private;
-
-	flush_workqueue(kdelayd_wq);
-
-	dm_put_device(ti, dc->dev_read);
-
-	if (dc->dev_write)
-		dm_put_device(ti, dc->dev_write);
-
-	mempool_destroy(dc->delayed_pool);
-	kfree(dc);
+	delay_dtr(ti);
+	return ret;
 }
 
-static int delay_bio(struct delay_c *dc, int delay, struct bio *bio)
+static int delay_bio(struct delay_c *dc, struct delay_class *c, struct bio *bio)
 {
 	struct dm_delay_info *delayed;
 	unsigned long expires = 0;
 
-	if (!delay || !atomic_read(&dc->may_delay))
-		return 1;
+	if (!c->delay)
+		return DM_MAPIO_REMAPPED;
 
-	delayed = mempool_alloc(dc->delayed_pool, GFP_NOIO);
+	delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
 
 	delayed->context = dc;
-	delayed->bio = bio;
-	delayed->expires = expires = jiffies + (delay * HZ / 1000);
-
-	mutex_lock(&delayed_bios_lock);
-
-	if (bio_data_dir(bio) == WRITE)
-		dc->writes++;
-	else
-		dc->reads++;
+	delayed->expires = expires = jiffies + msecs_to_jiffies(c->delay);
 
+	spin_lock(&dc->delayed_bios_lock);
+	if (unlikely(!dc->may_delay)) {
+		spin_unlock(&dc->delayed_bios_lock);
+		return DM_MAPIO_REMAPPED;
+	}
+	c->ops++;
 	list_add_tail(&delayed->list, &dc->delayed_bios);
+	spin_unlock(&dc->delayed_bios_lock);
 
-	mutex_unlock(&delayed_bios_lock);
-
-	queue_timeout(dc, expires);
+	if (delay_is_fast(dc))
+		wake_up_process(dc->worker);
+	else
+		queue_timeout(dc, expires);
 
-	return 0;
+	return DM_MAPIO_SUBMITTED;
 }
 
 static void delay_presuspend(struct dm_target *ti)
 {
 	struct delay_c *dc = ti->private;
 
-	atomic_set(&dc->may_delay, 0);
-	del_timer_sync(&dc->delay_timer);
-	flush_bios(flush_delayed_bios(dc, 1));
+	spin_lock(&dc->delayed_bios_lock);
+	dc->may_delay = false;
+	spin_unlock(&dc->delayed_bios_lock);
+
+	if (!delay_is_fast(dc))
+		timer_delete(&dc->delay_timer);
+	flush_delayed_bios(dc, true);
 }
 
 static void delay_resume(struct dm_target *ti)
 {
 	struct delay_c *dc = ti->private;
 
-	atomic_set(&dc->may_delay, 1);
+	dc->may_delay = true;
 }
 
 static int delay_map(struct dm_target *ti, struct bio *bio)
 {
 	struct delay_c *dc = ti->private;
-
-	if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) {
-		bio->bi_bdev = dc->dev_write->bdev;
-		if (bio_sectors(bio))
-			bio->bi_sector = dc->start_write +
-					 dm_target_offset(ti, bio->bi_sector);
-
-		return delay_bio(dc, dc->write_delay, bio);
+	struct delay_class *c;
+	struct dm_delay_info *delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
+
+	if (bio_data_dir(bio) == WRITE) {
+		if (unlikely(bio->bi_opf & REQ_PREFLUSH))
+			c = &dc->flush;
+		else
+			c = &dc->write;
+	} else {
+		c = &dc->read;
 	}
+	delayed->class = c;
+	bio_set_dev(bio, c->dev->bdev);
+	bio->bi_iter.bi_sector = c->start + dm_target_offset(ti, bio->bi_iter.bi_sector);
+
+	return delay_bio(dc, c, bio);
+}
 
-	bio->bi_bdev = dc->dev_read->bdev;
-	bio->bi_sector = dc->start_read + dm_target_offset(ti, bio->bi_sector);
+#ifdef CONFIG_BLK_DEV_ZONED
+static int delay_report_zones(struct dm_target *ti,
+		struct dm_report_zones_args *args, unsigned int nr_zones)
+{
+	struct delay_c *dc = ti->private;
+	struct delay_class *c = &dc->read;
 
-	return delay_bio(dc, dc->read_delay, bio);
+	return dm_report_zones(c->dev->bdev, c->start,
+			c->start + dm_target_offset(ti, args->next_sector),
+			args, nr_zones);
 }
+#else
+#define delay_report_zones	NULL
+#endif
+
+#define DMEMIT_DELAY_CLASS(c) \
+	DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay)
 
 static void delay_status(struct dm_target *ti, status_type_t type,
-			 unsigned status_flags, char *result, unsigned maxlen)
+			 unsigned int status_flags, char *result, unsigned int maxlen)
 {
 	struct delay_c *dc = ti->private;
 	int sz = 0;
 
 	switch (type) {
 	case STATUSTYPE_INFO:
-		DMEMIT("%u %u", dc->reads, dc->writes);
+		DMEMIT("%u %u %u", dc->read.ops, dc->write.ops, dc->flush.ops);
 		break;
 
 	case STATUSTYPE_TABLE:
-		DMEMIT("%s %llu %u", dc->dev_read->name,
-		       (unsigned long long) dc->start_read,
-		       dc->read_delay);
-		if (dc->dev_write)
-			DMEMIT(" %s %llu %u", dc->dev_write->name,
-			       (unsigned long long) dc->start_write,
-			       dc->write_delay);
+		DMEMIT_DELAY_CLASS(&dc->read);
+		if (dc->argc >= 6) {
+			DMEMIT(" ");
+			DMEMIT_DELAY_CLASS(&dc->write);
+		}
+		if (dc->argc >= 9) {
+			DMEMIT(" ");
+			DMEMIT_DELAY_CLASS(&dc->flush);
+		}
+		break;
+
+	case STATUSTYPE_IMA:
+		*result = '\0';
 		break;
 	}
 }
@@ -322,12 +433,15 @@ static int delay_iterate_devices(struct dm_target *ti,
 	struct delay_c *dc = ti->private;
 	int ret = 0;
 
-	ret = fn(ti, dc->dev_read, dc->start_read, ti->len, data);
+	ret = fn(ti, dc->read.dev, dc->read.start, ti->len, data);
+	if (ret)
+		goto out;
+	ret = fn(ti, dc->write.dev, dc->write.start, ti->len, data);
+	if (ret)
+		goto out;
+	ret = fn(ti, dc->flush.dev, dc->flush.start, ti->len, data);
 	if (ret)
 		goto out;
-
-	if (dc->dev_write)
-		ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data);
 
 out:
 	return ret;
@@ -335,59 +449,19 @@ out:
 
 static struct target_type delay_target = {
 	.name	     = "delay",
-	.version     = {1, 2, 1},
+	.version     = {1, 5, 0},
+	.features    = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM,
 	.module      = THIS_MODULE,
 	.ctr	     = delay_ctr,
 	.dtr	     = delay_dtr,
 	.map	     = delay_map,
+	.report_zones = delay_report_zones,
 	.presuspend  = delay_presuspend,
 	.resume	     = delay_resume,
 	.status	     = delay_status,
 	.iterate_devices = delay_iterate_devices,
 };
-
-static int __init dm_delay_init(void)
-{
-	int r = -ENOMEM;
-
-	kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
-	if (!kdelayd_wq) {
-		DMERR("Couldn't start kdelayd");
-		goto bad_queue;
-	}
-
-	delayed_cache = KMEM_CACHE(dm_delay_info, 0);
-	if (!delayed_cache) {
-		DMERR("Couldn't create delayed bio cache.");
-		goto bad_memcache;
-	}
-
-	r = dm_register_target(&delay_target);
-	if (r < 0) {
-		DMERR("register failed %d", r);
-		goto bad_register;
-	}
-
-	return 0;
-
-bad_register:
-	kmem_cache_destroy(delayed_cache);
-bad_memcache:
-	destroy_workqueue(kdelayd_wq);
-bad_queue:
-	return r;
-}
-
-static void __exit dm_delay_exit(void)
-{
-	dm_unregister_target(&delay_target);
-	kmem_cache_destroy(delayed_cache);
-	destroy_workqueue(kdelayd_wq);
-}
-
-/* Module hooks */
-module_init(dm_delay_init);
-module_exit(dm_delay_exit);
+module_dm(delay);
 
 MODULE_DESCRIPTION(DM_NAME " delay target");
 MODULE_AUTHOR("Heinz Mauelshagen <mauelshagen@redhat.com>");