Merge tag 'dm-3.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device-mapper updates from Mike Snitzer:
 "Add the ability to collect I/O statistics on user-defined regions of a
  device-mapper device.  This dm-stats code required the reintroduction
  of a div64_u64_rem() helper, but as a separate method that doesn't
  slow down div64_u64() -- especially on 32-bit systems.

  Allow the error target to replace request-based DM devices (e.g.
  multipath) in addition to bio-based DM devices.

  Various other small code fixes and improvements to thin-provisioning,
  DM cache and the DM ioctl interface"

* tag 'dm-3.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm stripe: silence a couple sparse warnings
  dm: add statistics support
  dm thin: always return -ENOSPC if no_free_space is set
  dm ioctl: cleanup error handling in table_load
  dm ioctl: increase granularity of type_lock when loading table
  dm ioctl: prevent rename to empty name or uuid
  dm thin: set pool read-only if breaking_sharing fails block allocation
  dm thin: prefix pool error messages with pool device name
  dm: allow error target to replace bio-based and request-based targets
  math64: New separate div64_u64_rem helper
  dm space map: optimise sm_ll_dec and sm_ll_inc
  dm btree: prefetch child nodes when walking tree for a dm_btree_del
  dm btree: use pop_frame in dm_btree_del to cleanup code
  dm cache: eliminate holes in cache structure
  dm cache: fix stacking of geometry limits
  dm thin: fix stacking of geometry limits
  dm thin: add data block size limits to Documentation
  dm cache: add data block size limits to code and Documentation
  dm cache: document metadata device is exclussive to a cache
  dm: stop using WQ_NON_REENTRANT

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/md/dm-stats.h b/drivers/md/dm-stats.h
new file mode 100644
index 00000000000..e7c4984bf23
--- /dev/null
+++ b/drivers/md/dm-stats.h
@@ -0,0 +1,40 @@
+#ifndef DM_STATS_H
+#define DM_STATS_H
+
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+
+int dm_statistics_init(void);
+void dm_statistics_exit(void);
+
+struct dm_stats {
+	struct mutex mutex;
+	struct list_head list;	/* list of struct dm_stat */
+	struct dm_stats_last_position __percpu *last;
+	sector_t last_sector;
+	unsigned last_rw;
+};
+
+struct dm_stats_aux {
+	bool merged;
+};
+
+void dm_stats_init(struct dm_stats *st);
+void dm_stats_cleanup(struct dm_stats *st);
+
+struct mapped_device;
+
+int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv,
+		     char *result, unsigned maxlen);
+
+void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw,
+			 sector_t bi_sector, unsigned bi_sectors, bool end,
+			 unsigned long duration, struct dm_stats_aux *aux);
+
+static inline bool dm_stats_used(struct dm_stats *st)
+{
+	return !list_empty(&st->list);
+}
+
+#endif