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-rw-r--r--drivers/md/dm.c13
-rw-r--r--drivers/md/dm.h11
-rw-r--r--include/linux/device-mapper.h2
3 files changed, 22 insertions, 4 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index b42e71bb9e6..d8544e1a4c1 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -482,9 +482,13 @@ static int clone_endio(struct bio *bio, unsigned int done, int error)
r = endio(tio->ti, bio, error, &tio->info);
if (r < 0)
error = r;
- else if (r > 0)
- /* the target wants another shot at the io */
+ else if (r == DM_ENDIO_INCOMPLETE)
+ /* The target will handle the io */
return 1;
+ else if (r) {
+ DMWARN("unimplemented target endio return value: %d", r);
+ BUG();
+ }
}
dec_pending(tio->io, error);
@@ -542,7 +546,7 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
atomic_inc(&tio->io->io_count);
sector = clone->bi_sector;
r = ti->type->map(ti, clone, &tio->info);
- if (r > 0) {
+ if (r == DM_MAPIO_REMAPPED) {
/* the bio has been remapped so dispatch it */
blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
@@ -560,6 +564,9 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
clone->bi_private = md->bs;
bio_put(clone);
free_tio(md, tio);
+ } else if (r) {
+ DMWARN("unimplemented target map return value: %d", r);
+ BUG();
}
}
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 81c98d6e35e..293d5ce62a2 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -33,6 +33,17 @@
#define SECTOR_SHIFT 9
/*
+ * Definitions of return values from target end_io function.
+ */
+#define DM_ENDIO_INCOMPLETE 1
+
+/*
+ * Definitions of return values from target map function.
+ */
+#define DM_MAPIO_SUBMITTED 0
+#define DM_MAPIO_REMAPPED 1
+
+/*
* Suspend feature flags
*/
#define DM_SUSPEND_LOCKFS_FLAG (1 << 0)
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 9194ff2d08c..2e5c42346c3 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -39,7 +39,7 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti);
* The map function must return:
* < 0: error
* = 0: The target will handle the io by resubmitting it later
- * > 0: simple remap complete
+ * = 1: simple remap complete
*/
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
union map_info *map_context);