dm log: add flush callback fn

Introduce a callback pointer from the log to dm-raid1 layer.

Before some region is set as "in-sync", we need to flush hardware cache on
all the disks. But the log module doesn't have access to the mirror_set
structure. So it will use this callback.

So far the callback is unused, it will be used in further patches.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

3 files changed, 9 insertions, 5 deletions

diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index d779f8c915dd..666a80e3602e 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -145,8 +145,9 @@ int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
 EXPORT_SYMBOL(dm_dirty_log_type_unregister);
 
 struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
-                                         struct dm_target *ti,
-                                         unsigned int argc, char **argv)
+                        struct dm_target *ti,
+                        int (*flush_callback_fn)(struct dm_target *ti),
+                        unsigned int argc, char **argv)
 {
         struct dm_dirty_log_type *type;
         struct dm_dirty_log *log;
@@ -161,6 +162,7 @@ struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
                 return NULL;
         }
 
+        log->flush_callback_fn = flush_callback_fn;
         log->type = type;
         if (type->ctr(log, ti, argc, argv)) {
                 kfree(log);
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 752a29e1855b..d44bc497dad9 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -896,7 +896,7 @@ static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
                 return NULL;
         }
 
-        dl = dm_dirty_log_create(argv[0], ti, param_count, argv + 2);
+        dl = dm_dirty_log_create(argv[0], ti, NULL, param_count, argv + 2);
         if (!dl) {
                 ti->error = "Error creating mirror dirty log";
                 return NULL;
diff --git a/include/linux/dm-dirty-log.h b/include/linux/dm-dirty-log.h
index 5e8b11d88f6f..7084503c3405 100644
--- a/include/linux/dm-dirty-log.h
+++ b/include/linux/dm-dirty-log.h
@@ -21,6 +21,7 @@ struct dm_dirty_log_type;
 
 struct dm_dirty_log {
         struct dm_dirty_log_type *type;
+        int (*flush_callback_fn)(struct dm_target *ti);
         void *context;
 };
 
@@ -136,8 +137,9 @@ int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type);
  * type->constructor/destructor() directly.
  */
 struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
-                                         struct dm_target *ti,
-                                         unsigned argc, char **argv);
+                        struct dm_target *ti,
+                        int (*flush_callback_fn)(struct dm_target *ti),
+                        unsigned argc, char **argv);
 void dm_dirty_log_destroy(struct dm_dirty_log *log);
 
 #endif  /* __KERNEL__ */