diff --git a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt
index 685bf3582abe..f346abbdd6ff 100644
--- a/Documentation/scsi/st.txt
+++ b/Documentation/scsi/st.txt
@@ -112,10 +112,8 @@ attempted).
 
 MINOR NUMBERS
 
-The tape driver currently supports 128 drives by default. This number
-can be increased by editing st.h and recompiling the driver if
-necessary. The upper limit is 2^17 drives if 4 modes for each drive
-are used.
+The tape driver currently supports up to 2^17 drives if 4 modes for
+each drive are used.
 
 The minor numbers consist of the following bit fields:
 
diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h
index b7a07c7bf4f8..f3eee0f9f40c 100644
--- a/drivers/scsi/st.h
+++ b/drivers/scsi/st.h
@@ -78,7 +78,7 @@ struct st_modedef {
 #define ST_MODE_SHIFT (7 - ST_NBR_MODE_BITS)
 #define ST_MODE_MASK ((ST_NBR_MODES - 1) << ST_MODE_SHIFT)
 
-#define ST_MAX_TAPES 128
+#define ST_MAX_TAPES (1 << (20 - (ST_NBR_MODE_BITS + 1)))
 #define ST_MAX_TAPE_ENTRIES  (ST_MAX_TAPES << (ST_NBR_MODE_BITS + 1))
 
 /* The status related to each partition */