drbd: properly use max_hw_sectors to limit the our bio size

To ease tracking of bios in some hash tables, we want it to
not cross certain boundaries (128k, used to be 32k).
We limit the maximum bio size using queue parameters.

Historically some defines and variables we use there have been named
max_segment_size, which was misguided. Rename them to max_bio_size,
and use [blk_]queue_max_hw_sectors where appropriate.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 85207b2..bcba274 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -512,7 +512,7 @@
 	u64	    d_size;  /* size of disk */
 	u64	    u_size;  /* user requested size */
 	u64	    c_size;  /* current exported size */
-	u32	    max_segment_size;  /* Maximal size of a BIO */
+	u32	    max_bio_size;  /* Maximal size of a BIO */
 	u16	    queue_order_type;  /* not yet implemented in DRBD*/
 	u16	    dds_flags; /* use enum dds_flags here. */
 } __packed;
@@ -1398,7 +1398,7 @@
  * With a value of 8 all IO in one 128K block make it to the same slot of the
  * hash table. */
 #define HT_SHIFT 8
-#define DRBD_MAX_SEGMENT_SIZE (1U<<(9+HT_SHIFT))
+#define DRBD_MAX_BIO_SIZE (1U<<(9+HT_SHIFT))
 
 #define DRBD_MAX_SIZE_H80_PACKET (1 << 15) /* The old header only allows packets up to 32Kib data */