[PATCH v4 3/5] dm: support retrieving struct dm_target from struct dm_dev

[Yang Yang]

Add a list to the struct dm_dev structure to store the associated
targets.

Signed-off-by: Yang Yang <yang.yang@xxxxxxxx>
---
 drivers/md/dm-table.c         | 16 ++++++++++++++++
 include/linux/device-mapper.h |  1 +
 2 files changed, 17 insertions(+)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index bd68af10afed..4817ddb660c4 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -2134,6 +2134,13 @@ void dm_table_postsuspend_targets(struct dm_table *t)
 	suspend_targets(t, POSTSUSPEND);
 }
 
+static int dm_link_dev_to_target(struct dm_target *ti, struct dm_dev *dev,
+		sector_t start, sector_t len, void *data)
+{
+	dev->ti = ti;
+	return 0;
+}
+
 int dm_table_resume_targets(struct dm_table *t)
 {
 	unsigned int i;
@@ -2162,6 +2169,15 @@ int dm_table_resume_targets(struct dm_table *t)
 			ti->type->resume(ti);
 	}
 
+	if (t->flush_pass_around) {
+		for (i = 0; i < t->num_targets; i++) {
+			struct dm_target *ti = dm_table_get_target(t, i);
+
+			if (ti->type->iterate_devices)
+				ti->type->iterate_devices(ti, dm_link_dev_to_target, NULL);
+		}
+	}
+
 	return 0;
 }
 
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 0893ff8c01b6..c6696f88bf66 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -169,6 +169,7 @@ struct dm_dev {
 	struct dax_device *dax_dev;
 	blk_mode_t mode;
 	char name[16];
+	struct dm_target *ti;
 };
 
 /*
-- 
2.34.1