[RFC 02/20] timens: Add timens_offsets
From: Dmitry Safonov <hidden>
Date: 2018-09-19 20:52:40
Also in:
lkml
Subsystem:
posix clocks and timers, the rest · Maintainers:
Anna-Maria Behnsen, Frederic Weisbecker, Thomas Gleixner, Linus Torvalds
From: Andrei Vagin <redacted> Introduce offsets for time namespace. They will contain adjustment needed to convert clocks to/from host's. Allocate one page for each time namespace that will be premapped into userspace with vvar pages. Signed-off-by: Andrei Vagin <redacted> Signed-off-by: Dmitry Safonov <redacted> --- include/linux/time_namespace.h | 2 ++ include/linux/timens_offsets.h | 8 ++++++++ kernel/time_namespace.c | 14 ++++++++++++-- 3 files changed, 22 insertions(+), 2 deletions(-) create mode 100644 include/linux/timens_offsets.h
diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index bf98f35efe07..4960c54f1b33 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h@@ -8,6 +8,7 @@ #include <linux/nsproxy.h> #include <linux/ns_common.h> #include <linux/err.h> +#include <linux/timens_offsets.h> struct user_namespace; extern struct user_namespace init_user_ns;
@@ -17,6 +18,7 @@ struct time_namespace { 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;
diff --git a/include/linux/timens_offsets.h b/include/linux/timens_offsets.h
new file mode 100644
index 000000000000..7d7cb68ea778
--- /dev/null
+++ b/include/linux/timens_offsets.h@@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_TIME_OFFSETS_H +#define _LINUX_TIME_OFFSETS_H + +struct timens_offsets { +}; + +#endif
diff --git a/kernel/time_namespace.c b/kernel/time_namespace.c
index 902cd9c22159..a985529754b4 100644
--- a/kernel/time_namespace.c
+++ b/kernel/time_namespace.c@@ -13,6 +13,7 @@ #include <linux/user_namespace.h> #include <linux/proc_ns.h> #include <linux/sched/task.h> +#include <linux/mm.h> static struct ucounts *inc_time_namespaces(struct user_namespace *ns) {
@@ -44,6 +45,7 @@ static struct time_namespace *clone_time_ns(struct user_namespace *user_ns, { struct time_namespace *ns; struct ucounts *ucounts; + struct page *page; int err; err = -ENOSPC;
@@ -56,15 +58,22 @@ static struct time_namespace *clone_time_ns(struct user_namespace *user_ns, if (!ns) goto fail_dec; + page = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!page) + goto fail_free; + ns->offsets = page_address(page); + BUILD_BUG_ON(sizeof(*ns->offsets) > PAGE_SIZE); + err = ns_alloc_inum(&ns->ns); if (err) - goto fail_free; + goto fail_page; ns->ucounts = ucounts; ns->ns.ops = &timens_operations; ns->user_ns = get_user_ns(user_ns); return ns; - +fail_page: + free_page((unsigned long)ns->offsets); fail_free: kfree(ns); fail_dec:
@@ -93,6 +102,7 @@ void free_time_ns(struct kref *kref) struct time_namespace *ns; ns = container_of(kref, struct time_namespace, kref); + free_page((unsigned long)ns->offsets); dec_time_namespaces(ns->ucounts); put_user_ns(ns->user_ns); ns_free_inum(&ns->ns);
--
2.13.6