dm bio prison v2: new interface for the bio prison

The deferred set is gone and all methods have _v2 appended to the end of
their names to allow for continued use of the original bio prison in DM
thin-provisioning.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/Makefile

@@ -11,6 +11,7 @@ dm-snapshot-y	+= dm-snap.o dm-exception-store.o dm-snap-transient.o \
 dm-mirror-y	+= dm-raid1.o
 dm-log-userspace-y \
 		+= dm-log-userspace-base.o dm-log-userspace-transfer.o
+dm-bio-prison-y += dm-bio-prison-v1.o dm-bio-prison-v2.o
 dm-thin-pool-y	+= dm-thin.o dm-thin-metadata.o
 dm-cache-y	+= dm-cache-target.o dm-cache-metadata.o dm-cache-policy.o
 dm-cache-smq-y   += dm-cache-policy-smq.o

drivers/md/dm-bio-prison.c → drivers/md/dm-bio-prison-v1.c

@@ -5,7 +5,8 @@
  */
 
 #include "dm.h"
-#include "dm-bio-prison.h"
+#include "dm-bio-prison-v1.h"
+#include "dm-bio-prison-v2.h"
 
 #include <linux/spinlock.h>
 #include <linux/mempool.h>
@@ -398,7 +399,7 @@ EXPORT_SYMBOL_GPL(dm_deferred_set_add_work);
 
 /*----------------------------------------------------------------*/
 
-static int __init dm_bio_prison_init(void)
+static int __init dm_bio_prison_init_v1(void)
 {
 	_cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0);
 	if (!_cell_cache)
@@ -407,12 +408,51 @@ static int __init dm_bio_prison_init(void)
 	return 0;
 }
 
-static void __exit dm_bio_prison_exit(void)
+static void dm_bio_prison_exit_v1(void)
 {
 	kmem_cache_destroy(_cell_cache);
 	_cell_cache = NULL;
 }
 
+static int (*_inits[])(void) __initdata = {
+	dm_bio_prison_init_v1,
+	dm_bio_prison_init_v2,
+};
+
+static void (*_exits[])(void) = {
+	dm_bio_prison_exit_v1,
+	dm_bio_prison_exit_v2,
+};
+
+static int __init dm_bio_prison_init(void)
+{
+	const int count = ARRAY_SIZE(_inits);
+
+	int r, i;
+
+	for (i = 0; i < count; i++) {
+		r = _inits[i]();
+		if (r)
+			goto bad;
+	}
+
+	return 0;
+
+      bad:
+	while (i--)
+		_exits[i]();
+
+	return r;
+}
+
+static void __exit dm_bio_prison_exit(void)
+{
+	int i = ARRAY_SIZE(_exits);
+
+	while (i--)
+		_exits[i]();
+}
+
 /*
  * module hooks
  */

drivers/md/dm-bio-prison.h → drivers/md/dm-bio-prison-v1.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011-2012 Red Hat, Inc.
+ * Copyright (C) 2011-2017 Red Hat, Inc.
  *
  * This file is released under the GPL.
  */