staging: lustre: lnet/selftest: fix compile error on UP build

When compiled without CONFIG_SMP, we get a compile error
as ->ctb_parts is not defined.

There is already a function, cfs_cpt_cpumask(), which will get the
cpumask we need, and which handles the UP case by returning a NULL pointer.
So use that and handle NULL.
Also avoid the #ifdef by allocating a cpumask_var and copying
into it, rather than sharing the mask.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Fixes: 6106c0f82481 ("staging: lustre: lnet: convert selftest to use workqueues")
Signed-off-by: NeilBrown <neilb@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lnet/selftest/module.c

@@ -110,7 +110,8 @@ lnet_selftest_init(void)
 	lst_init_step = LST_INIT_WI_TEST;
 	for (i = 0; i < nscheds; i++) {
 		int nthrs = cfs_cpt_weight(lnet_cpt_table(), i);
-		struct workqueue_attrs attrs;
+		struct workqueue_attrs attrs = {0};
+		cpumask_var_t *mask = cfs_cpt_cpumask(lnet_cpt_table(), i);
 
 		/* reserve at least one CPU for LND */
 		nthrs = max(nthrs - 1, 1);
@@ -121,14 +122,12 @@ lnet_selftest_init(void)
 			rc = -ENOMEM;
 			goto error;
 		}
-		attrs.nice = 0;
-		#ifdef CONFIG_CPUMASK_OFFSTACK
-		attrs.cpumask = lnet_cpt_table()->ctb_parts[i].cpt_cpumask;
-		#else
-		cpumask_copy(attrs.cpumask, lnet_cpt_table()->ctb_parts[i].cpt_cpumask);
-		#endif
-		attrs.no_numa = false;
-		apply_workqueue_attrs(lst_test_wq[i], &attrs);
+
+		if (mask && alloc_cpumask_var(&attrs.cpumask, GFP_KERNEL)) {
+			cpumask_copy(attrs.cpumask, *mask);
+			apply_workqueue_attrs(lst_test_wq[i], &attrs);
+			free_cpumask_var(attrs.cpumask);
+		}
 	}
 
 	rc = srpc_startup();