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Subject[patch 5/5] x86: Convert vsyscall gtod lock to raw_seqlock
vsyscall gtod seqlock is taken in the same context as xtime_lock and
therefor cannot be converted to a sleeping lock in preempt-rt.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/vgtod.h | 2 +-
arch/x86/kernel/vsyscall_64.c | 14 +++++++-------
arch/x86/vdso/vclock_gettime.c | 16 ++++++++--------
3 files changed, 16 insertions(+), 16 deletions(-)

Index: linux-2.6-tip/arch/x86/include/asm/vgtod.h
===================================================================
--- linux-2.6-tip.orig/arch/x86/include/asm/vgtod.h
+++ linux-2.6-tip/arch/x86/include/asm/vgtod.h
@@ -5,7 +5,7 @@
#include <linux/clocksource.h>

struct vsyscall_gtod_data {
- seqlock_t lock;
+ raw_seqlock_t lock;

/* open coded 'struct timespec' */
time_t wall_time_sec;
Index: linux-2.6-tip/arch/x86/kernel/vsyscall_64.c
===================================================================
--- linux-2.6-tip.orig/arch/x86/kernel/vsyscall_64.c
+++ linux-2.6-tip/arch/x86/kernel/vsyscall_64.c
@@ -59,7 +59,7 @@ int __vgetcpu_mode __section_vgetcpu_mod

struct vsyscall_gtod_data __vsyscall_gtod_data __section_vsyscall_gtod_data =
{
- .lock = __SEQLOCK_UNLOCKED(__vsyscall_gtod_data.lock),
+ .lock = __RAW_SEQLOCK_UNLOCKED(__vsyscall_gtod_data.lock),
.sysctl_enabled = 1,
};

@@ -67,10 +67,10 @@ void update_vsyscall_tz(void)
{
unsigned long flags;

- write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
+ write_raw_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
/* sys_tz has changed */
vsyscall_gtod_data.sys_tz = sys_tz;
- write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
+ write_raw_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
}

void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
@@ -78,7 +78,7 @@ void update_vsyscall(struct timespec *wa
{
unsigned long flags;

- write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
+ write_raw_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
/* copy vsyscall data */
vsyscall_gtod_data.clock.vread = clock->vread;
vsyscall_gtod_data.clock.cycle_last = clock->cycle_last;
@@ -89,7 +89,7 @@ void update_vsyscall(struct timespec *wa
vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec;
vsyscall_gtod_data.wall_to_monotonic = wall_to_monotonic;
vsyscall_gtod_data.wall_time_coarse = __current_kernel_time();
- write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
+ write_raw_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
}

/* RED-PEN may want to readd seq locking, but then the variable should be
@@ -126,7 +126,7 @@ static __always_inline void do_vgettimeo
unsigned long mult, shift, nsec;
cycle_t (*vread)(void);
do {
- seq = read_seqbegin(&__vsyscall_gtod_data.lock);
+ seq = read_raw_seqbegin(&__vsyscall_gtod_data.lock);

vread = __vsyscall_gtod_data.clock.vread;
if (unlikely(!__vsyscall_gtod_data.sysctl_enabled || !vread)) {
@@ -142,7 +142,7 @@ static __always_inline void do_vgettimeo

tv->tv_sec = __vsyscall_gtod_data.wall_time_sec;
nsec = __vsyscall_gtod_data.wall_time_nsec;
- } while (read_seqretry(&__vsyscall_gtod_data.lock, seq));
+ } while (read_raw_seqretry(&__vsyscall_gtod_data.lock, seq));

/* calculate interval: */
cycle_delta = (now - base) & mask;
Index: linux-2.6-tip/arch/x86/vdso/vclock_gettime.c
===================================================================
--- linux-2.6-tip.orig/arch/x86/vdso/vclock_gettime.c
+++ linux-2.6-tip/arch/x86/vdso/vclock_gettime.c
@@ -47,11 +47,11 @@ notrace static noinline int do_realtime(
{
unsigned long seq, ns;
do {
- seq = read_seqbegin(&gtod->lock);
+ seq = read_raw_seqbegin(&gtod->lock);
ts->tv_sec = gtod->wall_time_sec;
ts->tv_nsec = gtod->wall_time_nsec;
ns = vgetns();
- } while (unlikely(read_seqretry(&gtod->lock, seq)));
+ } while (unlikely(read_raw_seqretry(&gtod->lock, seq)));
timespec_add_ns(ts, ns);
return 0;
}
@@ -76,12 +76,12 @@ notrace static noinline int do_monotonic
{
unsigned long seq, ns, secs;
do {
- seq = read_seqbegin(&gtod->lock);
+ seq = read_raw_seqbegin(&gtod->lock);
secs = gtod->wall_time_sec;
ns = gtod->wall_time_nsec + vgetns();
secs += gtod->wall_to_monotonic.tv_sec;
ns += gtod->wall_to_monotonic.tv_nsec;
- } while (unlikely(read_seqretry(&gtod->lock, seq)));
+ } while (unlikely(read_raw_seqretry(&gtod->lock, seq)));
vset_normalized_timespec(ts, secs, ns);
return 0;
}
@@ -90,10 +90,10 @@ notrace static noinline int do_realtime_
{
unsigned long seq;
do {
- seq = read_seqbegin(&gtod->lock);
+ seq = read_raw_seqbegin(&gtod->lock);
ts->tv_sec = gtod->wall_time_coarse.tv_sec;
ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
- } while (unlikely(read_seqretry(&gtod->lock, seq)));
+ } while (unlikely(read_raw_seqretry(&gtod->lock, seq)));
return 0;
}

@@ -101,12 +101,12 @@ notrace static noinline int do_monotonic
{
unsigned long seq, ns, secs;
do {
- seq = read_seqbegin(&gtod->lock);
+ seq = read_raw_seqbegin(&gtod->lock);
secs = gtod->wall_time_coarse.tv_sec;
ns = gtod->wall_time_coarse.tv_nsec;
secs += gtod->wall_to_monotonic.tv_sec;
ns += gtod->wall_to_monotonic.tv_nsec;
- } while (unlikely(read_seqretry(&gtod->lock, seq)));
+ } while (unlikely(read_raw_seqretry(&gtod->lock, seq)));
vset_normalized_timespec(ts, secs, ns);
return 0;
}



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