Re: [patch 15/15] lib/vdso: Move VCLOCK_TIMENS to vdso_clock_modes

From: Christophe Leroy
Date: Wed Jan 15 2020 - 00:58:35 EST




Le 14/01/2020 Ã 19:52, Thomas Gleixner a ÃcritÂ:
Move the time namespace indicator clock mode to the other ones for
consistency sake.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
include/linux/clocksource.h | 3 +++
include/vdso/datapage.h | 2 --
kernel/time/namespace.c | 7 ++++---
lib/vdso/gettimeofday.c | 18 ++++++++++--------
4 files changed, 17 insertions(+), 13 deletions(-)

--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -34,6 +34,9 @@ enum vdso_clock_mode {
VDSO_ARCH_CLOCKMODES,
#endif
VDSO_CLOCKMODE_MAX,
+
+ /* Indicator for time namespace VDSO */ > + VDSO_CLOCKMODE_TIMENS = INT_MAX

Can we shorten the names a bit in order to avoid code line splits ? WOuldn't something like VDSO_CMODE_XXX be explicit enough ?

Christophe

};
/**
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -21,8 +21,6 @@
#define CS_RAW 1
#define CS_BASES (CS_RAW + 1)
-#define VCLOCK_TIMENS UINT_MAX
-
/**
* struct vdso_timestamp - basetime per clock_id
* @sec: seconds
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -8,6 +8,7 @@
#include <linux/user_namespace.h>
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
+#include <linux/clocksource.h>
#include <linux/seq_file.h>
#include <linux/proc_ns.h>
#include <linux/export.h>
@@ -172,8 +173,8 @@ static struct timens_offset offset_from_
* for vdso_data->clock_mode is a non-issue. The task is spin waiting for the
* update to finish and for 'seq' to become even anyway.
*
- * Timens page has vdso_data->clock_mode set to VCLOCK_TIMENS which enforces
- * the time namespace handling path.
+ * Timens page has vdso_data->clock_mode set to VDSO_CLOCKMODE_TIMENS which
+ * enforces the time namespace handling path.
*/
static void timens_setup_vdso_data(struct vdso_data *vdata,
struct time_namespace *ns)
@@ -183,7 +184,7 @@ static void timens_setup_vdso_data(struc
struct timens_offset boottime = offset_from_ts(ns->offsets.boottime);
vdata->seq = 1;
- vdata->clock_mode = VCLOCK_TIMENS;
+ vdata->clock_mode = VDSO_CLOCKMODE_TIMENS;
offset[CLOCK_MONOTONIC] = monotonic;
offset[CLOCK_MONOTONIC_RAW] = monotonic;
offset[CLOCK_MONOTONIC_COARSE] = monotonic;
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -116,10 +116,10 @@ static __always_inline int do_hres(const
do {
/*
- * Open coded to handle VCLOCK_TIMENS. Time namespace
+ * Open coded to handle VDSO_CLOCKMODE_TIMENS. Time namespace
* enabled tasks have a special VVAR page installed which
* has vd->seq set to 1 and vd->clock_mode set to
- * VCLOCK_TIMENS. For non time namespace affected tasks
+ * VDSO_CLOCKMODE_TIMENS. For non time namespace affected tasks
* this does not affect performance because if vd->seq is
* odd, i.e. a concurrent update is in progress the extra
* check for vd->clock_mode is just a few extra
@@ -128,7 +128,7 @@ static __always_inline int do_hres(const
*/
while (unlikely((seq = READ_ONCE(vd->seq)) & 1)) {
if (IS_ENABLED(CONFIG_TIME_NS) &&
- vd->clock_mode == VCLOCK_TIMENS)
+ vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
return do_hres_timens(vd, clk, ts);
cpu_relax();
}
@@ -200,12 +200,12 @@ static __always_inline int do_coarse(con
do {
/*
- * Open coded to handle VCLOCK_TIMENS. See comment in
+ * Open coded to handle VDSO_CLOCK_TIMENS. See comment in
* do_hres().
*/
while ((seq = READ_ONCE(vd->seq)) & 1) {
if (IS_ENABLED(CONFIG_TIME_NS) &&
- vd->clock_mode == VCLOCK_TIMENS)
+ vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
return do_coarse_timens(vd, clk, ts);
cpu_relax();
}
@@ -292,7 +292,7 @@ static __maybe_unused int
if (unlikely(tz != NULL)) {
if (IS_ENABLED(CONFIG_TIME_NS) &&
- vd->clock_mode == VCLOCK_TIMENS)
+ vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
vd = __arch_get_timens_vdso_data();
tz->tz_minuteswest = vd[CS_HRES_COARSE].tz_minuteswest;
@@ -308,7 +308,8 @@ static __maybe_unused __kernel_old_time_
const struct vdso_data *vd = __arch_get_vdso_data();
__kernel_old_time_t t;
- if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VCLOCK_TIMENS)
+ if (IS_ENABLED(CONFIG_TIME_NS) &&
+ vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
vd = __arch_get_timens_vdso_data();
t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
@@ -333,7 +334,8 @@ int __cvdso_clock_getres_common(clockid_
if (unlikely((u32) clock >= MAX_CLOCKS))
return -1;
- if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VCLOCK_TIMENS)
+ if (IS_ENABLED(CONFIG_TIME_NS) &&
+ vd->clock_mode == VDSO_CLOCKMODE_TIMENS)
vd = __arch_get_timens_vdso_data();
hrtimer_res = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res);