From: Guenter Roeck <linux@roeck-us.net>
Date: Thu, 30 May 2019 11:40:47 +0000 (-0700)
Subject: samples: fix pidfd-metadata compilation
X-Git-Tag: v5.2-rc4~33^2~2
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7c33277b9a9ada187f805b41ffbebe6c51622fb6;p=users%2Fwilly%2Flinux.git

samples: fix pidfd-metadata compilation

Define __NR_pidfd_send_signal if it isn't to prevent a compilation error.

To make pidfd-metadata compile on all arches, irrespective of whether
or not syscall numbers are assigned, define the syscall number to -1.
If it isn't defined this will cause the kernel to return -ENOSYS.

Fixes: 43c6afee48d4 ("samples: show race-free pidfd metadata access")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Christian Brauner <christian@brauner.io>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
[christian@brauner.io: tweak commit message]
Signed-off-by: Christian Brauner <christian@brauner.io>
---

diff --git a/samples/pidfd/pidfd-metadata.c b/samples/pidfd/pidfd-metadata.c
index 640f5f757c57..14b454448429 100644
--- a/samples/pidfd/pidfd-metadata.c
+++ b/samples/pidfd/pidfd-metadata.c
@@ -21,6 +21,10 @@
 #define CLONE_PIDFD 0x00001000
 #endif
 
+#ifndef __NR_pidfd_send_signal
+#define __NR_pidfd_send_signal -1
+#endif
+
 static int do_child(void *args)
 {
 	printf("%d\n", getpid());