IB/ipath: Enable 4KB MTU
Enable use of 4KB MTU. Since the driver uses more pinned memory for
receive buffers when the 4KB MTU is enabled, whether or not the fabric
supports that MTU, add a "mtu4096" module parameter that can be used to
limit the MTU to 2KB when it is known that 4KB MTUs can't be used
anyway.
Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/ipath/ipath_qp.c b/drivers/infiniband/hw/ipath/ipath_qp.c
index 087ed31..5c8094a 100644
--- a/drivers/infiniband/hw/ipath/ipath_qp.c
+++ b/drivers/infiniband/hw/ipath/ipath_qp.c
@@ -516,13 +516,13 @@
goto inval;
/*
- * Note: the chips support a maximum MTU of 4096, but the driver
- * hasn't implemented this feature yet, so don't allow Path MTU
- * values greater than 2048.
+ * don't allow invalid Path MTU values or greater than 2048
+ * unless we are configured for a 4KB MTU
*/
- if (attr_mask & IB_QP_PATH_MTU)
- if (attr->path_mtu > IB_MTU_2048)
- goto inval;
+ if ((attr_mask & IB_QP_PATH_MTU) &&
+ (ib_mtu_enum_to_int(attr->path_mtu) == -1 ||
+ (attr->path_mtu > IB_MTU_2048 && !ipath_mtu4096)))
+ goto inval;
if (attr_mask & IB_QP_PATH_MIG_STATE)
if (attr->path_mig_state != IB_MIG_MIGRATED &&
