1 files changed, 6 insertions, 2 deletions

diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index d1299e999723..530ff4c553f8 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -6,6 +6,7 @@
 #include <linux/types.h>
 #include <linux/workqueue.h>
 #include <linux/mutex.h>
+#include <scsi/scsi.h>
 
 struct request_queue;
 struct block_device;
@@ -25,12 +26,15 @@ struct blk_queue_tags;
  * NONE: Self evident.  Host adapter is not capable of scatter-gather.
  * ALL:  Means that the host adapter module can do scatter-gather,
  *       and that there is no limit to the size of the table to which
- *       we scatter/gather data.
+ *       we scatter/gather data.  The value we set here is the maximum
+ *       single element sglist.  To use chained sglists, the adapter
+ *       has to set a value beyond ALL (and correctly use the chain
+ *       handling API.
  * Anything else:  Indicates the maximum number of chains that can be
  *       used in one scatter-gather request.
  */
 #define SG_NONE 0
-#define SG_ALL 0xff
+#define SG_ALL  SCSI_MAX_SG_SEGMENTS
 
 #define MODE_UNKNOWN 0x00
 #define MODE_INITIATOR 0x01