[PATCH v4] arm: OABI compat: fix build when EPOLL is not enabled

From: Randy Dunlap
Date: Sat Feb 20 2021 - 13:48:41 EST


When CONFIG_EPOLL is not set/enabled, sys_oabi-compat.c has build
errors. Fix these by surrounding them with ifdef CONFIG_EPOLL/endif
and providing stubs for the "EPOLL is not set" case.

../arch/arm/kernel/sys_oabi-compat.c: In function 'sys_oabi_epoll_ctl':
../arch/arm/kernel/sys_oabi-compat.c:257:6: error: implicit declaration of function 'ep_op_has_event' [-Werror=implicit-function-declaration]
257 | if (ep_op_has_event(op) &&
| ^~~~~~~~~~~~~~~
../arch/arm/kernel/sys_oabi-compat.c:264:9: error: implicit declaration of function 'do_epoll_ctl'; did you mean 'sys_epoll_ctl'? [-Werror=implicit-function-declaration]
264 | return do_epoll_ctl(epfd, op, fd, &kernel, false);
| ^~~~~~~~~~~~

Fixes: c281634c8652 ("ARM: compat: remove KERNEL_DS usage in sys_oabi_epoll_ctl()")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx> # from an lkp .config file
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: Nicolas Pitre <nico@xxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: patches@xxxxxxxxxxxxxxx
Acked-by: Nicolas Pitre <nico@xxxxxxxxxxx>
---
KernelVersion: v5.11
I don't know what format is used for KernelVersion.
This patch applies to any Linux kernel v5.x and probably even older.

v2: use correct Fixes: tag (thanks, rmk)
v3: add patches@ to Cc: list
v4: add KernelVersion for Patch Daemon; add Acked-by from nico@)

arch/arm/kernel/sys_oabi-compat.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

--- linux-next-20201214.orig/arch/arm/kernel/sys_oabi-compat.c
+++ linux-next-20201214/arch/arm/kernel/sys_oabi-compat.c
@@ -248,6 +248,7 @@ struct oabi_epoll_event {
__u64 data;
} __attribute__ ((packed,aligned(4)));

+#ifdef CONFIG_EPOLL
asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
struct oabi_epoll_event __user *event)
{
@@ -298,6 +299,20 @@ asmlinkage long sys_oabi_epoll_wait(int
kfree(kbuf);
return err ? -EFAULT : ret;
}
+#else
+asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd,
+ struct oabi_epoll_event __user *event)
+{
+ return -EINVAL;
+}
+
+asmlinkage long sys_oabi_epoll_wait(int epfd,
+ struct oabi_epoll_event __user *events,
+ int maxevents, int timeout)
+{
+ return -EINVAL;
+}
+#endif

struct oabi_sembuf {
unsigned short sem_num;