[PATCH v2 06/11] uapi/fcntl: mark range as reserved

[Christian Brauner <brauner@kernel.org>]

Mark the range from -10000 to -40000 as a range reserved for special
in-kernel values. Move the PIDFD_SELF_*/PIDFD_THREAD_* sentinels over so
all the special values are in one place.

Signed-off-by: Christian Brauner <brauner@kernel.org>
---
 include/uapi/linux/fcntl.h            | 16 ++++++++++++++++
 include/uapi/linux/pidfd.h            | 15 ---------------
 tools/testing/selftests/pidfd/pidfd.h |  2 +-
 3 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index a15ac2fa4b20..ba4a698d2f33 100644
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h
@@ -90,10 +90,26 @@
 #define DN_ATTRIB	0x00000020	/* File changed attibutes */
 #define DN_MULTISHOT	0x80000000	/* Don't remove notifier */
 
+/* Reserved kernel ranges [-100], [-10000, -40000]. */
 #define AT_FDCWD		-100    /* Special value for dirfd used to
 					   indicate openat should use the
 					   current working directory. */
 
+/*
+ * The concept of process and threads in userland and the kernel is a confusing
+ * one - within the kernel every thread is a 'task' with its own individual PID,
+ * however from userland's point of view threads are grouped by a single PID,
+ * which is that of the 'thread group leader', typically the first thread
+ * spawned.
+ *
+ * To cut the Gideon knot, for internal kernel usage, we refer to
+ * PIDFD_SELF_THREAD to refer to the current thread (or task from a kernel
+ * perspective), and PIDFD_SELF_THREAD_GROUP to refer to the current thread
+ * group leader...
+ */
+#define PIDFD_SELF_THREAD		-10000 /* Current thread. */
+#define PIDFD_SELF_THREAD_GROUP		-10001 /* Current thread group leader. */
+
 
 /* Generic flags for the *at(2) family of syscalls. */
 
diff --git a/include/uapi/linux/pidfd.h b/include/uapi/linux/pidfd.h
index c27a4e238e4b..957db425d459 100644
--- a/include/uapi/linux/pidfd.h
+++ b/include/uapi/linux/pidfd.h
@@ -42,21 +42,6 @@
 #define PIDFD_COREDUMP_USER	(1U << 2) /* coredump was done as the user. */
 #define PIDFD_COREDUMP_ROOT	(1U << 3) /* coredump was done as root. */
 
-/*
- * The concept of process and threads in userland and the kernel is a confusing
- * one - within the kernel every thread is a 'task' with its own individual PID,
- * however from userland's point of view threads are grouped by a single PID,
- * which is that of the 'thread group leader', typically the first thread
- * spawned.
- *
- * To cut the Gideon knot, for internal kernel usage, we refer to
- * PIDFD_SELF_THREAD to refer to the current thread (or task from a kernel
- * perspective), and PIDFD_SELF_THREAD_GROUP to refer to the current thread
- * group leader...
- */
-#define PIDFD_SELF_THREAD		-10000 /* Current thread. */
-#define PIDFD_SELF_THREAD_GROUP		-20000 /* Current thread group leader. */
-
 /*
  * ...and for userland we make life simpler - PIDFD_SELF refers to the current
  * thread, PIDFD_SELF_PROCESS refers to the process thread group leader.
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
index efd74063126e..5dfeb1bdf399 100644
--- a/tools/testing/selftests/pidfd/pidfd.h
+++ b/tools/testing/selftests/pidfd/pidfd.h
@@ -56,7 +56,7 @@
 #endif
 
 #ifndef PIDFD_SELF_THREAD_GROUP
-#define PIDFD_SELF_THREAD_GROUP		-20000 /* Current thread group leader. */
+#define PIDFD_SELF_THREAD_GROUP		-10001 /* Current thread group leader. */
 #endif
 
 #ifndef PIDFD_SELF

-- 
2.47.2