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Subject[PATCHv3 05/27] timerfd/timens: Take into account ns clock offsets
Date
From: Andrei Vagin <avagin@gmail.com>

Make timerfd respect timens offsets.
Provide a helper timens_ktime_to_host() that is useful to wire up
timens to different kernel subsystems.

Signed-off-by: Andrei Vagin <avagin@openvz.org>
Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
fs/timerfd.c | 8 +++++--
include/linux/hrtimer.h | 1 +
include/linux/time_namespace.h | 40 ++++++++++++++++++++++++++++++++++
kernel/time/hrtimer.c | 3 +++
4 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 6a6fc8aa1de7..a55ade09eee1 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -26,6 +26,7 @@
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <linux/rcupdate.h>
+#include <linux/time_namespace.h>

struct timerfd_ctx {
union {
@@ -179,6 +180,8 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
htmode = (flags & TFD_TIMER_ABSTIME) ?
HRTIMER_MODE_ABS: HRTIMER_MODE_REL;

+ htmode |= HRTIMER_MODE_NS;
+
texp = timespec64_to_ktime(ktmr->it_value);
ctx->expired = 0;
ctx->ticks = 0;
@@ -197,9 +200,10 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,

if (texp != 0) {
if (isalarm(ctx)) {
- if (flags & TFD_TIMER_ABSTIME)
+ if (flags & TFD_TIMER_ABSTIME) {
+ texp = timens_ktime_to_host(clockid, texp);
alarm_start(&ctx->t.alarm, texp);
- else
+ } else
alarm_start_relative(&ctx->t.alarm, texp);
} else {
hrtimer_start(&ctx->t.tmr, texp, htmode);
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 2e8957eac4d4..4b9c89c797ee 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -38,6 +38,7 @@ enum hrtimer_mode {
HRTIMER_MODE_REL = 0x01,
HRTIMER_MODE_PINNED = 0x02,
HRTIMER_MODE_SOFT = 0x04,
+ HRTIMER_MODE_NS = 0x08,

HRTIMER_MODE_ABS_PINNED = HRTIMER_MODE_ABS | HRTIMER_MODE_PINNED,
HRTIMER_MODE_REL_PINNED = HRTIMER_MODE_REL | HRTIMER_MODE_PINNED,
diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index 5f0da6858b10..988414f7f791 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -56,6 +56,41 @@ static inline void timens_add_boottime(struct timespec64 *ts)
*ts = timespec64_add(*ts, ns_offsets->monotonic_boottime_offset);
}

+static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
+{
+ struct timens_offsets *ns_offsets = current->nsproxy->time_ns->offsets;
+ struct timespec64 *offset;
+ ktime_t koff;
+
+ if (!ns_offsets)
+ return tim;
+
+ switch (clockid) {
+ case CLOCK_MONOTONIC:
+ case CLOCK_MONOTONIC_RAW:
+ case CLOCK_MONOTONIC_COARSE:
+ offset = &ns_offsets->monotonic_time_offset;
+ break;
+ case CLOCK_BOOTTIME:
+ case CLOCK_BOOTTIME_ALARM:
+ offset = &ns_offsets->monotonic_boottime_offset;
+ break;
+ default:
+ return tim;
+ }
+
+ koff = timespec64_to_ktime(*offset);
+ if (tim < koff)
+ tim = 0;
+ else if (KTIME_MAX - tim < -koff)
+ tim = KTIME_MAX;
+ else
+ tim = ktime_sub(tim, koff);
+
+ return tim;
+}
+
+
#else
static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
{
@@ -82,6 +117,11 @@ static inline int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *ts

static inline void timens_add_monotonic(struct timespec64 *ts) {}
static inline void timens_add_boottime(struct timespec64 *ts) {}
+
+static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
+{
+ return tim;
+}
#endif

#endif /* _LINUX_TIMENS_H */
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 41dfff23c1f9..484a0efec1df 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -42,6 +42,7 @@
#include <linux/timer.h>
#include <linux/freezer.h>
#include <linux/compat.h>
+#include <linux/time_namespace.h>

#include <linux/uaccess.h>

@@ -1069,6 +1070,8 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,

if (mode & HRTIMER_MODE_REL)
tim = ktime_add_safe(tim, base->get_time());
+ else if (mode & HRTIMER_MODE_NS)
+ tim = timens_ktime_to_host(base->clockid, tim);

tim = hrtimer_update_lowres(timer, tim, mode);

--
2.21.0
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