dm log: split suspend

There are now two phases to a suspend in device-mapper -
presuspend and postsuspend.  This patch removes the
single 'suspend' in the logging API and replaces it with
'presuspend' and 'postsuspend' functions to align it
better with core device-mapper.

A subsequent patch will make use of 'presuspend'.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-log.c

@@ -696,7 +696,7 @@ static struct dirty_log_type _disk_type = {
 	.module = THIS_MODULE,
 	.ctr = disk_ctr,
 	.dtr = disk_dtr,
-	.suspend = disk_flush,
+	.postsuspend = disk_flush,
 	.resume = disk_resume,
 	.get_region_size = core_get_region_size,
 	.is_clean = core_is_clean,

drivers/md/dm-log.h

@@ -32,7 +32,8 @@ struct dirty_log_type {
 	 * There are times when we don't want the log to touch
 	 * the disk.
 	 */
-	int (*suspend)(struct dirty_log *log);
+	int (*presuspend)(struct dirty_log *log);
+	int (*postsuspend)(struct dirty_log *log);
 	int (*resume)(struct dirty_log *log);
 
 	/*

drivers/md/dm-raid1.c

@@ -1305,7 +1305,7 @@ static void mirror_postsuspend(struct dm_target *ti)
 	wait_event(_kmirrord_recovery_stopped,
 		   !atomic_read(&ms->rh.recovery_in_flight));
 
-	if (log->type->suspend && log->type->suspend(log))
+	if (log->type->postsuspend && log->type->postsuspend(log))
 		/* FIXME: need better error handling */
 		DMWARN("log suspend failed");
 }