dm: allow remove to be deferred

[platform/adaptation/renesas_rcar/renesas_kernel.git] / drivers / md / dm.c

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index b3e26c7..0704c52 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -49,6 +49,11 @@ static unsigned int _major = 0;
 static DEFINE_IDR(_minor_idr);
 
 static DEFINE_SPINLOCK(_minor_lock);
+
+static void do_deferred_remove(struct work_struct *w);
+
+static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
+
 /*
  * For bio-based dm.
  * One of these is allocated per bio.
@@ -116,6 +121,7 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
 #define DMF_DELETING 4
 #define DMF_NOFLUSH_SUSPENDING 5
 #define DMF_MERGE_IS_OPTIONAL 6
+#define DMF_DEFERRED_REMOVE 7
 
 /*
  * A dummy definition to make RCU happy.
@@ -299,6 +305,8 @@ out_free_io_cache:
 
 static void local_exit(void)
 {
+       flush_scheduled_work();
+
        kmem_cache_destroy(_rq_tio_cache);
        kmem_cache_destroy(_io_cache);
        unregister_blkdev(_major, _name);
@@ -404,7 +412,10 @@ static void dm_blk_close(struct gendisk *disk, fmode_t mode)
 
        spin_lock(&_minor_lock);
 
-       atomic_dec(&md->open_count);
+       if (atomic_dec_and_test(&md->open_count) &&
+           (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
+               schedule_work(&deferred_remove_work);
+
        dm_put(md);
 
        spin_unlock(&_minor_lock);
@@ -418,14 +429,18 @@ int dm_open_count(struct mapped_device *md)
 /*
  * Guarantees nothing is using the device before it's deleted.
  */
-int dm_lock_for_deletion(struct mapped_device *md)
+int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
 {
        int r = 0;
 
        spin_lock(&_minor_lock);
 
-       if (dm_open_count(md))
+       if (dm_open_count(md)) {
                r = -EBUSY;
+               if (mark_deferred)
+                       set_bit(DMF_DEFERRED_REMOVE, &md->flags);
+       } else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
+               r = -EEXIST;
        else
                set_bit(DMF_DELETING, &md->flags);
 
@@ -434,6 +449,27 @@ int dm_lock_for_deletion(struct mapped_device *md)
        return r;
 }
 
+int dm_cancel_deferred_remove(struct mapped_device *md)
+{
+       int r = 0;
+
+       spin_lock(&_minor_lock);
+
+       if (test_bit(DMF_DELETING, &md->flags))
+               r = -EBUSY;
+       else
+               clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
+
+       spin_unlock(&_minor_lock);
+
+       return r;
+}
+
+static void do_deferred_remove(struct work_struct *w)
+{
+       dm_deferred_remove();
+}
+
 sector_t dm_get_size(struct mapped_device *md)
 {
        return get_capacity(md->disk);
@@ -2894,6 +2930,11 @@ int dm_suspended_md(struct mapped_device *md)
        return test_bit(DMF_SUSPENDED, &md->flags);
 }
 
+int dm_test_deferred_remove_flag(struct mapped_device *md)
+{
+       return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
+}
+
 int dm_suspended(struct dm_target *ti)
 {
        return dm_suspended_md(dm_table_get_md(ti->table));