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From:   Dmitry Safonov <dima@arista.com>
To:     linux-kernel@vger.kernel.org
Cc:     Dmitry Safonov <0x7f454c46@gmail.com>,
        Andrei Vagin <avagin@openvz.org>,
        Dmitry Safonov <dima@arista.com>,
        Adrian Reber <adrian@lisas.de>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Jann Horn <jannh@google.com>, Jeff Dike <jdike@addtoit.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Pavel Emelyanov <xemul@virtuozzo.com>,
        Shuah Khan <shuah@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        containers@lists.linux-foundation.org, criu@openvz.org,
        linux-api@vger.kernel.org, x86@kernel.org
Subject: [PATCHv5 09/37] posix-clocks: Introduce CLOCK_MONOTONIC time namespace offsets
Date:   Mon, 29 Jul 2019 22:56:51 +0100
Message-Id: <20190729215758.28405-10-dima@arista.com>
In-Reply-To: <20190729215758.28405-1-dima@arista.com>
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From: Andrei Vagin <avagin@openvz.org>

Add monotonic time virtualisation for time namespace.
Introduce timespec for monotionic clock into timens offsets and wire
clock_gettime() syscall.

Signed-off-by: Andrei Vagin <avagin@openvz.org>
Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 include/linux/time_namespace.h | 8 ++++++++
 include/linux/timens_offsets.h | 1 +
 kernel/time/posix-stubs.c      | 2 ++
 kernel/time/posix-timers.c     | 4 ++++
 4 files changed, 15 insertions(+)

diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index b6985aa87479..186c134fe222 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -40,6 +40,13 @@ static inline void put_time_ns(struct time_namespace *ns)
 	kref_put(&ns->kref, free_time_ns);
 }
 
+static inline void timens_add_monotonic(struct timespec64 *ts)
+{
+	struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
+
+	if (ns_offsets)
+		*ts = timespec64_add(*ts, ns_offsets->monotonic);
+}
 
 #else
 static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
@@ -65,6 +72,7 @@ static inline int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *ts
 	return 0;
 }
 
+static inline void timens_add_monotonic(struct timespec64 *ts) {}
 #endif
 
 #endif /* _LINUX_TIMENS_H */
diff --git a/include/linux/timens_offsets.h b/include/linux/timens_offsets.h
index 7d7cb68ea778..eaac2c82be5c 100644
--- a/include/linux/timens_offsets.h
+++ b/include/linux/timens_offsets.h
@@ -3,6 +3,7 @@
 #define _LINUX_TIME_OFFSETS_H
 
 struct timens_offsets {
+	struct timespec64 monotonic;
 };
 
 #endif
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 67df65f887ac..17c67e0aecd8 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -14,6 +14,7 @@
 #include <linux/ktime.h>
 #include <linux/timekeeping.h>
 #include <linux/posix-timers.h>
+#include <linux/time_namespace.h>
 #include <linux/compat.h>
 
 #ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
@@ -77,6 +78,7 @@ int do_clock_gettime(clockid_t which_clock, struct timespec64 *tp)
 		break;
 	case CLOCK_MONOTONIC:
 		ktime_get_ts64(tp);
+		timens_add_monotonic(tp);
 		break;
 	case CLOCK_BOOTTIME:
 		ktime_get_boottime_ts64(tp);
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index aae7ab53790d..cfeb0477d1f9 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -30,6 +30,7 @@
 #include <linux/hashtable.h>
 #include <linux/compat.h>
 #include <linux/nospec.h>
+#include <linux/time_namespace.h>
 
 #include "timekeeping.h"
 #include "posix-timers.h"
@@ -196,6 +197,7 @@ static int posix_clock_realtime_adj(const clockid_t which_clock,
 int posix_get_timespec(clockid_t which_clock, struct timespec64 *tp)
 {
 	ktime_get_ts64(tp);
+	timens_add_monotonic(tp);
 	return 0;
 }
 
@@ -210,6 +212,7 @@ static ktime_t posix_get_ktime(clockid_t which_clock)
 static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec64 *tp)
 {
 	ktime_get_raw_ts64(tp);
+	timens_add_monotonic(tp);
 	return 0;
 }
 
@@ -224,6 +227,7 @@ static int posix_get_monotonic_coarse(clockid_t which_clock,
 						struct timespec64 *tp)
 {
 	ktime_get_coarse_ts64(tp);
+	timens_add_monotonic(tp);
 	return 0;
 }
 
-- 
2.22.0