As suggested by Jeff, checking if dynamic SL support

was explicitly requested. If it was, but opensm-devel
package is not found, warn and abort.
Otherwise, doing the best effort: if opensm-devel found,
enable dynamic SL. If it's not found, disable dynamic
SL and build OMPI w/o it.

This commit was SVN r24852.

ompi/config/ompi_check_openib.m4

@@ -162,14 +162,14 @@ dnl                        [enable_openib_ibcm="$enableval"], [enable_openib_ibc
         [AC_HELP_STRING([--enable-openib-dynamic-sl],
                         [Enable openib BTL to query Subnet Manager for IB SL (default: enabled)])],
         [enable_openib_dynamic_sl="$enableval"],
-        [enable_openib_dynamic_sl="yes"])
+        [enable_openib_dynamic_sl="not_provided"])
 
     # Set these up so that we can do an AC_DEFINE below
     # (unconditionally)
     $1_have_xrc=0
     $1_have_rdmacm=0
     $1_have_ibcm=0
-    $1_have_dynamic_sl=0
+    $1_have_opensm_devel=0
 
     # If we have the openib stuff available, find out what we've got
     AS_IF([test "$ompi_check_openib_happy" = "yes"],
@@ -186,18 +186,14 @@ dnl                        [enable_openib_ibcm="$enableval"], [enable_openib_ibc
                AC_CHECK_FUNCS([ibv_create_xrc_rcv_qp], [$1_have_xrc=1])
            fi
 
-           if test "$enable_openib_dynamic_sl" = "yes"; then
-               # We need ib_types.h file, which is installed with opensm-devel
-               # package. However, ib_types.h has a bad include directive,
-               # which will cause AC_CHECK_HEADER to fail.
-               # So instead, we will look for another file that is also
-               # installed as part of opensm-devel package and included in
-               # ib_types.h, but it doesn't include any other IB-related files.
-               AC_CHECK_HEADER([infiniband/complib/cl_types_osd.h],
-                               [$1_have_dynamic_sl=1],
-                               [AC_MSG_WARN([opensm-devel package not found - please install it or disable dynamic SL support with \"--disable-openib-dynamic-sl\"])],
-                               [])
-           fi
+           # We need ib_types.h file, which is installed with opensm-devel
+           # package. However, ib_types.h has a bad include directive,
+           # which will cause AC_CHECK_HEADER to fail.
+           # So instead, we will look for another file that is also
+           # installed as part of opensm-devel package and included in
+           # ib_types.h, but it doesn't include any other IB-related files.
+           AC_CHECK_HEADER([infiniband/complib/cl_types_osd.h],
+                           [$1_have_opensm_devel=1], [], [])
 
            # Do we have a recent enough RDMA CM?  Need to have the
            # rdma_get_peer_addr (inline) function (originally appeared
@@ -268,15 +264,20 @@ dnl           fi
         AC_MSG_RESULT([no])
     fi
 
-    AC_MSG_CHECKING([if dynamic SL is enabled])
-    AC_DEFINE_UNQUOTED([OMPI_ENABLE_DYNAMIC_SL], [$$1_have_dynamic_sl],
-        [Enable features required for dynamic SL support])
-    if test "1" = "$$1_have_dynamic_sl"; then
-        AC_MSG_RESULT([yes])
-    else
-        AC_MSG_RESULT([no])
+    if test "no" != "$enable_openib_dynamic_sl"; then
+        # Abort if dynamic SL support was explicitly requested but opensm-devel
+        # package wasn't found. Otherwise, OMPI will be built w/o dynamic SL.
+        AC_MSG_CHECKING([if can use dynamic SL support])
+        AS_IF([test "$$1_have_opensm_devel" = "1"],
+              [AC_MSG_RESULT([yes])],
+              [AC_MSG_RESULT([no])
+               AS_IF([test "$enable_openib_dynamic_sl" = "yes"],
+                     [AC_MSG_WARN([--enable-openib-dynamic-sl was specified but the])
+                      AC_MSG_WARN([appropriate header files could not be found])
+                      AC_MSG_WARN([Please install opensm-devel if you need dynamic SL support])
+                      AC_MSG_ERROR([Cannot continue])])])
     fi
-    
+
     AC_MSG_CHECKING([if OpenFabrics RDMACM support is enabled])
     AC_DEFINE_UNQUOTED([OMPI_HAVE_RDMACM], [$$1_have_rdmacm],
         [Whether RDMA CM is available or not])