posix-timers: Make timer_settime() time namespace aware

Wire timer_settime() syscall into time namespace virtualization.

sys_timer_settime() calls the ktime->timer_set() callback. Right now,
common_timer_set() is the only implementation for the callback.

The user-supplied expiry value is converted from timespec64 to ktime and
then timens_ktime_to_host() can be used to convert namespace's time to the
host time.

Inside a time namespace kernel's time differs by a fixed offset from a
user-supplied time, but only absolute values (TIMER_ABSTIME) must be
converted.

Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-15-dima@arista.com

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index d26b915b227aee079305e642f44f2ad108fb1b7b..473082b0b57fdc12403ce80b9a3b0adfe055244e 100644 (file)
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -885,6 +885,8 @@ int common_timer_set(struct k_itimer *timr, int flags,
 
        timr->it_interval = timespec64_to_ktime(new_setting->it_interval);
        expires = timespec64_to_ktime(new_setting->it_value);
+       if (flags & TIMER_ABSTIME)
+               expires = timens_ktime_to_host(timr->it_clock, expires);
        sigev_none = timr->it_sigev_notify == SIGEV_NONE;
 
        kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none);