dm: support non power of two target max_io_len

[deliverable/linux.git] / include / linux / device-mapper.h

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index d70cbb2ada2529fbf971c8debcce1747883f117f..b19c1e189a6841576e1f4c148bc696ae1993d862 100644 (file)
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -186,8 +186,8 @@ struct dm_target {
        sector_t begin;
        sector_t len;
 
-       /* Always a power of 2 */
-       sector_t split_io;
+       /* If non-zero, maximum size of I/O submitted to a target. */
+       uint32_t max_io_len;
 
        /*
         * A number of zero-length barrier requests that will be submitted
@@ -357,6 +357,11 @@ void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callback
  */
 int dm_table_complete(struct dm_table *t);
 
+/*
+ * Target may require that it is never sent I/O larger than len.
+ */
+int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
+
 /*
  * Table reference counting.
  */