[RFC PATCH] uapi, posix-timers: provide clockid-related macros and functions to UAPI

[Eugene Syromiatnikov <esyr@redhat.com>]

As of now, there is no interface exposed for converting pid/fd into
clockid and vice versa; linuxptp, for example, has been carrying these
definitions in missing.h header for quite some time[1].

[1] https://sourceforge.net/p/linuxptp/code/ci/af380e86/tree/missing.h

Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
---
 include/linux/posix-timers.h | 47 +-------------------------------------------
 include/uapi/linux/time.h    | 47 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 46 deletions(-)

diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index ee7e987e..eef1be8 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -5,6 +5,7 @@
 #include <linux/spinlock.h>
 #include <linux/list.h>
 #include <linux/sched.h>
+#include <linux/time.h>
 #include <linux/timex.h>
 #include <linux/alarmtimer.h>
 
@@ -17,52 +18,6 @@ struct cpu_timer_list {
 	int firing;
 };
 
-/*
- * Bit fields within a clockid:
- *
- * The most significant 29 bits hold either a pid or a file descriptor.
- *
- * Bit 2 indicates whether a cpu clock refers to a thread or a process.
- *
- * Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3.
- *
- * A clockid is invalid if bits 2, 1, and 0 are all set.
- */
-#define CPUCLOCK_PID(clock)		((pid_t) ~((clock) >> 3))
-#define CPUCLOCK_PERTHREAD(clock) \
-	(((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)
-
-#define CPUCLOCK_PERTHREAD_MASK	4
-#define CPUCLOCK_WHICH(clock)	((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
-#define CPUCLOCK_CLOCK_MASK	3
-#define CPUCLOCK_PROF		0
-#define CPUCLOCK_VIRT		1
-#define CPUCLOCK_SCHED		2
-#define CPUCLOCK_MAX		3
-#define CLOCKFD			CPUCLOCK_MAX
-#define CLOCKFD_MASK		(CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK)
-
-static inline clockid_t make_process_cpuclock(const unsigned int pid,
-		const clockid_t clock)
-{
-	return ((~pid) << 3) | clock;
-}
-static inline clockid_t make_thread_cpuclock(const unsigned int tid,
-		const clockid_t clock)
-{
-	return make_process_cpuclock(tid, clock | CPUCLOCK_PERTHREAD_MASK);
-}
-
-static inline clockid_t fd_to_clockid(const int fd)
-{
-	return make_process_cpuclock((unsigned int) fd, CLOCKFD);
-}
-
-static inline int clockid_to_fd(const clockid_t clk)
-{
-	return ~(clk >> 3);
-}
-
 #define REQUEUE_PENDING 1
 
 /**
diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h
index 6b56a22..0043110 100644
--- a/include/uapi/linux/time.h
+++ b/include/uapi/linux/time.h
@@ -97,4 +97,51 @@ struct __kernel_old_timeval {
  */
 #define TIMER_ABSTIME			0x01
 
+/*
+ * Bit fields within a clockid:
+ *
+ * The most significant 29 bits hold either a pid or a file descriptor.
+ *
+ * Bit 2 indicates whether a cpu clock refers to a thread or a process.
+ *
+ * Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3.
+ *
+ * A clockid is invalid if bits 2, 1, and 0 are all set.
+ */
+#define CPUCLOCK_PID(clock)		((pid_t) ~((clock) >> 3))
+#define CPUCLOCK_PERTHREAD(clock) \
+	(((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)
+
+#define CPUCLOCK_PERTHREAD_MASK	4
+#define CPUCLOCK_WHICH(clock)	((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
+#define CPUCLOCK_CLOCK_MASK	3
+#define CPUCLOCK_PROF		0
+#define CPUCLOCK_VIRT		1
+#define CPUCLOCK_SCHED		2
+#define CPUCLOCK_MAX		3
+#define CLOCKFD			CPUCLOCK_MAX
+#define CLOCKFD_MASK		(CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK)
+
+static inline clockid_t make_process_cpuclock(const unsigned int pid,
+		const clockid_t clock)
+{
+	return ((~pid) << 3) | clock;
+}
+static inline clockid_t make_thread_cpuclock(const unsigned int tid,
+		const clockid_t clock)
+{
+	return make_process_cpuclock(tid, clock | CPUCLOCK_PERTHREAD_MASK);
+}
+
+static inline clockid_t fd_to_clockid(const int fd)
+{
+	return make_process_cpuclock((unsigned int) fd, CLOCKFD);
+}
+
+static inline int clockid_to_fd(const clockid_t clk)
+{
+	return ~(clk >> 3);
+}
+
+
 #endif /* _UAPI_LINUX_TIME_H */
-- 
2.1.4