Configure out AIO support

This patchs adds the CONFIG_AIO option which allows to remove support
for asynchronous I/O operations, that are not necessarly used by
applications, particularly on embedded devices. As this is a
size-reduction option, it depends on CONFIG_EMBEDDED. It allows to
save ~7 kilobytes of kernel code/data:

   text	   data	    bss	    dec	    hex	filename
1115067	 119180	 217088	1451335	 162547	vmlinux
1108025	 119048	 217088	1444161	 160941	vmlinux.new
  -7042    -132       0   -7174   -1C06 +/-

This patch has been originally written by Matt Mackall
<mpm@selenic.com>, and is part of the Linux Tiny project.

[randy.dunlap@oracle.com: build fix]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 7 insertions, 0 deletions

diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 503d8d4eb80a..a77b27b11b04 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -126,6 +126,11 @@ cond_syscall(sys_vm86);
 cond_syscall(compat_sys_ipc);
 cond_syscall(compat_sys_sysctl);
 cond_syscall(sys_flock);
+cond_syscall(sys_io_setup);
+cond_syscall(sys_io_destroy);
+cond_syscall(sys_io_submit);
+cond_syscall(sys_io_cancel);
+cond_syscall(sys_io_getevents);
 
 /* arch-specific weak syscall entries */
 cond_syscall(sys_pciconfig_read);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9792c315676a..617d41e4d6a0 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1281,6 +1281,7 @@ static struct ctl_table fs_table[] = {
                 .extra2         = &two,
         },
 #endif
+#ifdef CONFIG_AIO
         {
                 .procname       = "aio-nr",
                 .data           = &aio_nr,
@@ -1295,6 +1296,7 @@ static struct ctl_table fs_table[] = {
                 .mode           = 0644,
                 .proc_handler   = &proc_doulongvec_minmax,
         },
+#endif /* CONFIG_AIO */
 #ifdef CONFIG_INOTIFY_USER
         {
                 .ctl_name       = FS_INOTIFY,