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-rw-r--r--include/linux/device-mapper.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 49c2362977fd..fc36a4d07723 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -21,6 +21,7 @@ typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
union map_info {
void *ptr;
unsigned long long ll;
+ unsigned flush_request;
};
/*
@@ -168,6 +169,16 @@ struct dm_target {
sector_t split_io;
/*
+ * A number of zero-length barrier requests that will be submitted
+ * to the target for the purpose of flushing cache.
+ *
+ * The request number will be placed in union map_info->flush_request.
+ * It is a responsibility of the target driver to remap these requests
+ * to the real underlying devices.
+ */
+ unsigned num_flush_requests;
+
+ /*
* These are automatically filled in by
* dm_table_get_device.
*/