[PATCH 1/7] POSIX clock ID check function

[Erez Geva]

Add function to check whether a clock ID refer to
a file descriptor of a POSIX dynamic clock.

Signed-off-by: Erez Geva <erez.geva....@siemens.com>
---
 include/linux/posix-timers.h | 5 +++++
 kernel/time/posix-timers.c   | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 896c16d2c5fb..7cb551bbb763 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -57,6 +57,11 @@ static inline int clockid_to_fd(const clockid_t clk)
        return ~(clk >> 3);
 }
 
+static inline bool is_clockid_fd_clock(const clockid_t clk)
+{
+       return (clk < 0) && ((clk & CLOCKFD_MASK) == CLOCKFD);
+}
+
 #ifdef CONFIG_POSIX_TIMERS
 
 /**
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index bf540f5a4115..806465233303 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1400,7 +1400,7 @@ static const struct k_clock *clockid_to_kclock(const 
clockid_t id)
        clockid_t idx = id;
 
        if (id < 0) {
-               return (id & CLOCKFD_MASK) == CLOCKFD ?
+               return is_clockid_fd_clock(id) ?
                        &clock_posix_dynamic : &clock_posix_cpu;
        }
 
-- 
2.20.1