1 files changed, 132 insertions, 9 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 9e39d2b64bf8..b3e26c7d1417 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -60,6 +60,7 @@ struct dm_io {
 	struct bio *bio;
 	unsigned long start_time;
 	spinlock_t endio_lock;
+	struct dm_stats_aux stats_aux;
 };
 
 /*
@@ -198,6 +199,8 @@ struct mapped_device {
 
 	/* zero-length flush that will be cloned and submitted to targets */
 	struct bio flush_bio;
+
+	struct dm_stats stats;
 };
 
 /*
@@ -208,10 +211,55 @@ struct dm_md_mempools {
 	struct bio_set *bs;
 };
 
-#define MIN_IOS 256
+#define RESERVED_BIO_BASED_IOS		16
+#define RESERVED_REQUEST_BASED_IOS	256
+#define RESERVED_MAX_IOS		1024
 static struct kmem_cache *_io_cache;
 static struct kmem_cache *_rq_tio_cache;
 
+/*
+ * Bio-based DM's mempools' reserved IOs set by the user.
+ */
+static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
+
+/*
+ * Request-based DM's mempools' reserved IOs set by the user.
+ */
+static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
+
+static unsigned __dm_get_reserved_ios(unsigned *reserved_ios,
+				      unsigned def, unsigned max)
+{
+	unsigned ios = ACCESS_ONCE(*reserved_ios);
+	unsigned modified_ios = 0;
+
+	if (!ios)
+		modified_ios = def;
+	else if (ios > max)
+		modified_ios = max;
+
+	if (modified_ios) {
+		(void)cmpxchg(reserved_ios, ios, modified_ios);
+		ios = modified_ios;
+	}
+
+	return ios;
+}
+
+unsigned dm_get_reserved_bio_based_ios(void)
+{
+	return __dm_get_reserved_ios(&reserved_bio_based_ios,
+				     RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS);
+}
+EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
+
+unsigned dm_get_reserved_rq_based_ios(void)
+{
+	return __dm_get_reserved_ios(&reserved_rq_based_ios,
+				     RESERVED_REQUEST_BASED_IOS, RESERVED_MAX_IOS);
+}
+EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
+
 static int __init local_init(void)
 {
 	int r = -ENOMEM;
@@ -269,6 +317,7 @@ static int (*_inits[])(void) __initdata = {
 	dm_io_init,
 	dm_kcopyd_init,
 	dm_interface_init,
+	dm_statistics_init,
 };
 
 static void (*_exits[])(void) = {
@@ -279,6 +328,7 @@ static void (*_exits[])(void) = {
 	dm_io_exit,
 	dm_kcopyd_exit,
 	dm_interface_exit,
+	dm_statistics_exit,
 };
 
 static int __init dm_init(void)
@@ -384,6 +434,16 @@ int dm_lock_for_deletion(struct mapped_device *md)
 	return r;
 }
 
+sector_t dm_get_size(struct mapped_device *md)
+{
+	return get_capacity(md->disk);
+}
+
+struct dm_stats *dm_get_stats(struct mapped_device *md)
+{
+	return &md->stats;
+}
+
 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 {
 	struct mapped_device *md = bdev->bd_disk->private_data;
@@ -466,8 +526,9 @@ static int md_in_flight(struct mapped_device *md)
 static void start_io_acct(struct dm_io *io)
 {
 	struct mapped_device *md = io->md;
+	struct bio *bio = io->bio;
 	int cpu;
-	int rw = bio_data_dir(io->bio);
+	int rw = bio_data_dir(bio);
 
 	io->start_time = jiffies;
 
@@ -476,6 +537,10 @@ static void start_io_acct(struct dm_io *io)
 	part_stat_unlock();
 	atomic_set(&dm_disk(md)->part0.in_flight[rw],
 		atomic_inc_return(&md->pending[rw]));
+
+	if (unlikely(dm_stats_used(&md->stats)))
+		dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_sector,
+				    bio_sectors(bio), false, 0, &io->stats_aux);
 }
 
 static void end_io_acct(struct dm_io *io)
@@ -491,6 +556,10 @@ static void end_io_acct(struct dm_io *io)
 	part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
 	part_stat_unlock();
 
+	if (unlikely(dm_stats_used(&md->stats)))
+		dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_sector,
+				    bio_sectors(bio), true, duration, &io->stats_aux);
+
 	/*
 	 * After this is decremented the bio must not be touched if it is
 	 * a flush.
@@ -1519,7 +1588,7 @@ static void _dm_request(struct request_queue *q, struct bio *bio)
 	return;
 }
 
-static int dm_request_based(struct mapped_device *md)
+int dm_request_based(struct mapped_device *md)
 {
 	return blk_queue_stackable(md->queue);
 }
@@ -1946,8 +2015,7 @@ static struct mapped_device *alloc_dev(int minor)
 	add_disk(md->disk);
 	format_dev_t(md->name, MKDEV(_major, minor));
 
-	md->wq = alloc_workqueue("kdmflush",
-				 WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
+	md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0);
 	if (!md->wq)
 		goto bad_thread;
 
@@ -1959,6 +2027,8 @@ static struct mapped_device *alloc_dev(int minor)
 	md->flush_bio.bi_bdev = md->bdev;
 	md->flush_bio.bi_rw = WRITE_FLUSH;
 
+	dm_stats_init(&md->stats);
+
 	/* Populate the mapping, nobody knows we exist yet */
 	spin_lock(&_minor_lock);
 	old_md = idr_replace(&_minor_idr, md, minor);
@@ -2010,6 +2080,7 @@ static void free_dev(struct mapped_device *md)
 
 	put_disk(md->disk);
 	blk_cleanup_queue(md->queue);
+	dm_stats_cleanup(&md->stats);
 	module_put(THIS_MODULE);
 	kfree(md);
 }
@@ -2151,7 +2222,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
 	/*
 	 * Wipe any geometry if the size of the table changed.
 	 */
-	if (size != get_capacity(md->disk))
+	if (size != dm_get_size(md))
 		memset(&md->geometry, 0, sizeof(md->geometry));
 
 	__set_size(md, size);
@@ -2236,11 +2307,13 @@ void dm_unlock_md_type(struct mapped_device *md)
 
 void dm_set_md_type(struct mapped_device *md, unsigned type)
 {
+	BUG_ON(!mutex_is_locked(&md->type_lock));
 	md->type = type;
 }
 
 unsigned dm_get_md_type(struct mapped_device *md)
 {
+	BUG_ON(!mutex_is_locked(&md->type_lock));
 	return md->type;
 }
 
@@ -2250,6 +2323,17 @@ struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
 }
 
 /*
+ * The queue_limits are only valid as long as you have a reference
+ * count on 'md'.
+ */
+struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
+{
+	BUG_ON(!atomic_read(&md->holders));
+	return &md->queue->limits;
+}
+EXPORT_SYMBOL_GPL(dm_get_queue_limits);
+
+/*
  * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
  */
 static int dm_init_request_based_queue(struct mapped_device *md)
@@ -2695,6 +2779,38 @@ out:
 	return r;
 }
 
+/*
+ * Internal suspend/resume works like userspace-driven suspend. It waits
+ * until all bios finish and prevents issuing new bios to the target drivers.
+ * It may be used only from the kernel.
+ *
+ * Internal suspend holds md->suspend_lock, which prevents interaction with
+ * userspace-driven suspend.
+ */
+
+void dm_internal_suspend(struct mapped_device *md)
+{
+	mutex_lock(&md->suspend_lock);
+	if (dm_suspended_md(md))
+		return;
+
+	set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+	synchronize_srcu(&md->io_barrier);
+	flush_workqueue(md->wq);
+	dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
+}
+
+void dm_internal_resume(struct mapped_device *md)
+{
+	if (dm_suspended_md(md))
+		goto done;
+
+	dm_queue_flush(md);
+
+done:
+	mutex_unlock(&md->suspend_lock);
+}
+
 /*-----------------------------------------------------------------
  * Event notification.
  *---------------------------------------------------------------*/
@@ -2802,18 +2918,18 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, u
 
 	if (type == DM_TYPE_BIO_BASED) {
 		cachep = _io_cache;
-		pool_size = 16;
+		pool_size = dm_get_reserved_bio_based_ios();
 		front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
 	} else if (type == DM_TYPE_REQUEST_BASED) {
 		cachep = _rq_tio_cache;
-		pool_size = MIN_IOS;
+		pool_size = dm_get_reserved_rq_based_ios();
 		front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
 		/* per_bio_data_size is not used. See __bind_mempools(). */
 		WARN_ON(per_bio_data_size != 0);
 	} else
 		goto out;
 
-	pools->io_pool = mempool_create_slab_pool(MIN_IOS, cachep);
+	pools->io_pool = mempool_create_slab_pool(pool_size, cachep);
 	if (!pools->io_pool)
 		goto out;
 
@@ -2864,6 +2980,13 @@ module_exit(dm_exit);
 
 module_param(major, uint, 0);
 MODULE_PARM_DESC(major, "The major number of the device mapper");
+
+module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
+
+module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
+
 MODULE_DESCRIPTION(DM_NAME " driver");
 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");