posix-timers: Introduce a syscall for clock tuning.

A new syscall is introduced that allows tuning of a POSIX clock. The
new call, clock_adjtime, takes two parameters, the clock ID and a
pointer to a struct timex. Any ADJTIMEX(2) operation may be requested
via this system call, but various POSIX clocks may or may not support
tuning.

[ tglx: Adapted to the posix-timer cleanup series. Avoid copy_to_user
  	in the error case ]

Signed-off-by: Richard Cochran <richard.cochran@omicron.at>
Acked-by: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20110201134419.869804645@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 8206255a547c..79a1cea7f6ed 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -4,6 +4,7 @@
 #include <linux/spinlock.h>
 #include <linux/list.h>
 #include <linux/sched.h>
+#include <linux/timex.h>
 
 union cpu_time_count {
         cputime_t cpu;
@@ -71,6 +72,7 @@ struct k_clock {
         int (*clock_set) (const clockid_t which_clock,
                           const struct timespec *tp);
         int (*clock_get) (const clockid_t which_clock, struct timespec * tp);
+        int (*clock_adj) (const clockid_t which_clock, struct timex *tx);
         int (*timer_create) (struct k_itimer *timer);
         int (*nsleep) (const clockid_t which_clock, int flags,
                        struct timespec *, struct timespec __user *);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 18cd0684fc4e..bfacab921239 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -311,6 +311,8 @@ asmlinkage long sys_clock_settime(clockid_t which_clock,
                                 const struct timespec __user *tp);
 asmlinkage long sys_clock_gettime(clockid_t which_clock,
                                 struct timespec __user *tp);
+asmlinkage long sys_clock_adjtime(clockid_t which_clock,
+                                struct timex __user *tx);
 asmlinkage long sys_clock_getres(clockid_t which_clock,
                                 struct timespec __user *tp);
 asmlinkage long sys_clock_nanosleep(clockid_t which_clock, int flags,