Introduce a new Kconfig CONFIG_NUMA_SYSFS for drivers/base/node.c
which just provides sysfs interface, so that when we select
CONFIG_NUMA, we don't have to enable the sysfs interface too.

This by the way fixes a randconfig build error when NUMA && !SYSFS.

Signed-off-by: WANG Cong <amwang@redhat.com>

---
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 4c5701c..f34abe6 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -10,7 +10,7 @@ obj-$(CONFIG_HAS_DMA)	+= dma-mapping.o
 obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
 obj-$(CONFIG_ISA)	+= isa.o
 obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
-obj-$(CONFIG_NUMA)	+= node.o
+obj-$(CONFIG_NUMA_SYSFS)	+= node.o
 obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o
 obj-$(CONFIG_SMP)	+= topology.o
 obj-$(CONFIG_IOMMU_API) += iommu.o
diff --git a/mm/Kconfig b/mm/Kconfig
index 8ca47a5..f89ab19 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -340,6 +340,16 @@ choice
 	  benefit.
 endchoice
 
+config NUMA_SYSFS
+	bool "Enable NUMA sysfs interface for user-space"
+	depends on NUMA
+	depends on SYSFS
+	default y
+	help
+	  This enables NUMA sysfs interface, /sys/devices/system/node/,
+	  for user-space tools, like numactl. If you have enabled NUMA,
+	  probably you also need this one.
+
 #
 # UP and nommu archs use km based percpu allocator
 #