Merge tag 'for-4.15/dm' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - a few conversions from atomic_t to ref_count_t

 - a DM core fix for a race during device destruction that could result
   in a BUG_ON

 - a stable@ fix for a DM cache race condition that could lead to data
   corruption when operating in writeback mode (writethrough is default)

 - various DM cache cleanups and improvements

 - add DAX support to the DM log-writes target

 - a fix for the DM zoned target's ability to deal with the last zone of
   the drive being smaller than all others

 - a stable@ DM crypt and DM integrity fix for a negative check that was
   to restrictive (prevented slab debug with XFS ontop of DM crypt from
   working)

 - a DM raid target fix for a panic that can occur when forcing a raid
   to sync

* tag 'for-4.15/dm' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (25 commits)
  dm cache: lift common migration preparation code to alloc_migration()
  dm cache: remove usused deferred_cells member from struct cache
  dm cache policy smq: allocate cache blocks in order
  dm cache policy smq: change max background work from 10240 to 4096 blocks
  dm cache background tracker: limit amount of background work that may be issued at once
  dm cache policy smq: take origin idle status into account when queuing writebacks
  dm cache policy smq: handle races with queuing background_work
  dm raid: fix panic when attempting to force a raid to sync
  dm integrity: allow unaligned bv_offset
  dm crypt: allow unaligned bv_offset
  dm: small cleanup in dm_get_md()
  dm: fix race between dm_get_from_kobject() and __dm_destroy()
  dm: allocate struct mapped_device with kvzalloc
  dm zoned: ignore last smaller runt zone
  dm space map metadata: use ARRAY_SIZE
  dm log writes: add support for DAX
  dm log writes: add support for inline data buffers
  dm cache: simplify get_per_bio_data() by removing data_size argument
  dm cache: remove all obsolete writethrough-specific code
  dm cache: submit writethrough writes in parallel to origin and cache
  ...

drivers/md/dm.c

@@ -24,6 +24,7 @@
 #include <linux/delay.h>
 #include <linux/wait.h>
 #include <linux/pr.h>
+#include <linux/refcount.h>
 
 #define DM_MSG_PREFIX "core"
 
@@ -98,7 +99,7 @@ struct dm_md_mempools {
 
 struct table_device {
 	struct list_head list;
-	atomic_t count;
+	refcount_t count;
 	struct dm_dev dm_dev;
 };
 
@@ -685,10 +686,11 @@ int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
 
 		format_dev_t(td->dm_dev.name, dev);
 
-		atomic_set(&td->count, 0);
+		refcount_set(&td->count, 1);
 		list_add(&td->list, &md->table_devices);
+	} else {
+		refcount_inc(&td->count);
 	}
-	atomic_inc(&td->count);
 	mutex_unlock(&md->table_devices_lock);
 
 	*result = &td->dm_dev;
@@ -701,7 +703,7 @@ void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
 	struct table_device *td = container_of(d, struct table_device, dm_dev);
 
 	mutex_lock(&md->table_devices_lock);
-	if (atomic_dec_and_test(&td->count)) {
+	if (refcount_dec_and_test(&td->count)) {
 		close_table_device(td, md);
 		list_del(&td->list);
 		kfree(td);
@@ -718,7 +720,7 @@ static void free_table_devices(struct list_head *devices)
 		struct table_device *td = list_entry(tmp, struct table_device, list);
 
 		DMWARN("dm_destroy: %s still exists with %d references",
-		       td->dm_dev.name, atomic_read(&td->count));
+		       td->dm_dev.name, refcount_read(&td->count));
 		kfree(td);
 	}
 }
@@ -1684,7 +1686,7 @@ static struct mapped_device *alloc_dev(int minor)
 	struct mapped_device *md;
 	void *old_md;
 
-	md = kzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id);
+	md = kvzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id);
 	if (!md) {
 		DMWARN("unable to allocate device, out of memory.");
 		return NULL;
@@ -1784,7 +1786,7 @@ bad_io_barrier:
 bad_minor:
 	module_put(THIS_MODULE);
 bad_module_get:
-	kfree(md);
+	kvfree(md);
 	return NULL;
 }
 
@@ -1803,7 +1805,7 @@ static void free_dev(struct mapped_device *md)
 	free_minor(minor);
 
 	module_put(THIS_MODULE);
-	kfree(md);
+	kvfree(md);
 }
 
 static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
@@ -2061,17 +2063,12 @@ struct mapped_device *dm_get_md(dev_t dev)
 	spin_lock(&_minor_lock);
 
 	md = idr_find(&_minor_idr, minor);
-	if (md) {
-		if ((md == MINOR_ALLOCED ||
-		     (MINOR(disk_devt(dm_disk(md))) != minor) ||
-		     dm_deleting_md(md) ||
-		     test_bit(DMF_FREEING, &md->flags))) {
-			md = NULL;
-			goto out;
-		}
-		dm_get(md);
+	if (!md || md == MINOR_ALLOCED || (MINOR(disk_devt(dm_disk(md))) != minor) ||
+	    test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
+		md = NULL;
+		goto out;
 	}
-
+	dm_get(md);
 out:
 	spin_unlock(&_minor_lock);
 
@@ -2698,11 +2695,15 @@ struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
 
 	md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
 
-	if (test_bit(DMF_FREEING, &md->flags) ||
-	    dm_deleting_md(md))
-		return NULL;
-
+	spin_lock(&_minor_lock);
+	if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
+		md = NULL;
+		goto out;
+	}
 	dm_get(md);
+out:
+	spin_unlock(&_minor_lock);
+
 	return md;
 }