[PATCH] lib/flex_array: make build optional

[Aristeu Rozanski]

From: Aristeu Rozanski <arozansk@xxxxxxxxxx>

flex_array currently is built unconditionally:
	text    data     bss     dec     hex filename
	2294    1008    1568    4870    1306 lib/flex_array.o
	2294    1008    1568    4870    1306 (TOTALS)

and it's used by procfs, selinux and openvswitch. This patch is
useful for situations in which memory footprint is a concern and
those features aren't used.

Cc: Changli Gao <xiaosuo@xxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Cc: Jesse Gross <jesse@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Pravin Shelar <pshelar@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
Signed-off-by: Aristeu Rozanski <arozansk@xxxxxxxxxx>
---
 fs/proc/Kconfig          |  1 +
 lib/Kconfig              | 10 ++++++++++
 lib/Makefile             |  3 ++-
 net/openvswitch/Kconfig  |  1 +
 security/selinux/Kconfig |  1 +
 5 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig
index 2183fcf..2d624b7 100644
--- a/fs/proc/Kconfig
+++ b/fs/proc/Kconfig
@@ -1,6 +1,7 @@
 config PROC_FS
 	bool "/proc file system support" if EXPERT
 	default y
+	select FLEX_ARRAY
 	help
 	  This is a virtual file system providing information about the status
 	  of the system. "Virtual" means that it doesn't take up any space on
diff --git a/lib/Kconfig b/lib/Kconfig
index 54cf309..675920b 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -432,6 +432,16 @@ config GLOB_SELFTEST
 	  module load) by a small amount, so you're welcome to play with
 	  it, but you probably don't need it.
 
+config FLEX_ARRAY
+	bool "Flexible array"
+	default n
+	help
+	  This option enables an implementation of flexible arrays which
+	  allows creating arrays of fixed size elements with an arbritrary
+	  size without requiring the single allocation of a contiguous area.
+
+	  See Documentation/flexible-arrays.txt
+
 #
 # Netlink attribute parsing support is select'ed if needed
 #
diff --git a/lib/Makefile b/lib/Makefile
index 7512dc9..9c12cbc 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -24,7 +24,7 @@ obj-y	+= lockref.o
 
 obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
 	 bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
-	 gcd.o lcm.o list_sort.o uuid.o flex_array.o iovec.o clz_ctz.o \
+	 gcd.o lcm.o list_sort.o uuid.o iovec.o clz_ctz.o \
 	 bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \
 	 percpu-refcount.o percpu_ida.o hash.o rhashtable.o
 obj-y += string_helpers.o
@@ -35,6 +35,7 @@ obj-$(CONFIG_TEST_LKM) += test_module.o
 obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
 obj-$(CONFIG_TEST_BPF) += test_bpf.o
 obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
+obj-$(CONFIG_FLEX_ARRAY) += flex_array.o
 
 ifeq ($(CONFIG_DEBUG_KOBJECT),y)
 CFLAGS_kobject.o += -DDEBUG
diff --git a/net/openvswitch/Kconfig b/net/openvswitch/Kconfig
index ba3bb82..1d979ce 100644
--- a/net/openvswitch/Kconfig
+++ b/net/openvswitch/Kconfig
@@ -5,6 +5,7 @@
 config OPENVSWITCH
 	tristate "Open vSwitch"
 	select LIBCRC32C
+	select FLEX_ARRAY
 	---help---
 	  Open vSwitch is a multilayer Ethernet switch targeted at virtualized
 	  environments.  In addition to supporting a variety of features
diff --git a/security/selinux/Kconfig b/security/selinux/Kconfig
index bca1b74..cfcc7c1 100644
--- a/security/selinux/Kconfig
+++ b/security/selinux/Kconfig
@@ -2,6 +2,7 @@ config SECURITY_SELINUX
 	bool "NSA SELinux Support"
 	depends on SECURITY_NETWORK && AUDIT && NET && INET
 	select NETWORK_SECMARK
+	select FLEX_ARRAY
 	default n
 	help
 	  This selects NSA Security-Enhanced Linux (SELinux).
-- 
1.8.3.1

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