Commit af993f58 authored by Andrei Vagin's avatar Andrei Vagin Committed by Thomas Gleixner
Browse files

time: Add timens_offsets to be used for tasks in time namespace 



Introduce offsets for time namespace. They will contain an adjustment
needed to convert clocks to/from host's.

A new namespace is created with the same offsets as the time namespace
of the current process.

Co-developed-by: default avatarDmitry Safonov <dima@arista.com>
Signed-off-by: default avatarAndrei Vagin <avagin@openvz.org>
Signed-off-by: default avatarDmitry Safonov <dima@arista.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-5-dima@arista.com
parent 769071ac

include/linux/time_namespace.h

+22 −0
Original line number Diff line number Diff line
@@ -12,11 +12,17 @@ 
struct user_namespace;

extern struct user_namespace init_user_ns;



struct timens_offsets {

	struct timespec64 monotonic;

	struct timespec64 boottime;

};



struct time_namespace {

	struct kref		kref;

	struct user_namespace	*user_ns;

	struct ucounts		*ucounts;

	struct ns_common	ns;

	struct timens_offsets	offsets;

} __randomize_layout;



extern struct time_namespace init_time_ns;
@@ -39,6 +45,20 @@ 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;



	*ts = timespec64_add(*ts, ns_offsets->monotonic);

}



static inline void timens_add_boottime(struct timespec64 *ts)

{

	struct timens_offsets *ns_offsets = &current->nsproxy->time_ns->offsets;



	*ts = timespec64_add(*ts, ns_offsets->boottime);

}



#else

static inline struct time_namespace *get_time_ns(struct time_namespace *ns)

{
@@ -66,6 +86,8 @@ static inline int timens_on_fork(struct nsproxy *nsproxy, 
	return 0;

}



static inline void timens_add_monotonic(struct timespec64 *ts) { }

static inline void timens_add_boottime(struct timespec64 *ts) { }

#endif



#endif /* _LINUX_TIMENS_H */

kernel/time/namespace.c

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/slab.h>

#include <linux/cred.h>

#include <linux/err.h>

#include <linux/mm.h>



static struct ucounts *inc_time_namespaces(struct user_namespace *ns)

{
@@ -60,6 +61,7 @@ static struct time_namespace *clone_time_ns(struct user_namespace *user_ns, 
	ns->ucounts = ucounts;

	ns->ns.ops = &timens_operations;

	ns->user_ns = get_user_ns(user_ns);

	ns->offsets = old_ns->offsets;

	return ns;



fail_free:

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