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[PATCH] posix-timers: Fix clock_nanosleep() doesn't return the remain…
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…ing time in compatibility mode

The clock_nanosleep() function does not return the time remaining when the
sleep is interrupted by a signal.

This patch creates a new call out, compat_clock_nanosleep_restart(), which
handles returning the remaining time after a sleep is interrupted.  This
patch revives clock_nanosleep_restart().  It is now accessed via the new
call out.  The compat_clock_nanosleep_restart() is used for compatibility
access.

Since this is implemented in compatibility mode the normal path is
virtually unaffected - no real performance impact.

Signed-off-by: Toyo Abe <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Roland McGrath <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Toyo Abe authored and Linus Torvalds committed Sep 29, 2006

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1 parent 9c4751f commit 1711ef3
Showing 6 changed files with 81 additions and 15 deletions.
1 change: 1 addition & 0 deletions include/linux/hrtimer.h
Original file line number Diff line number Diff line change
@@ -138,6 +138,7 @@ extern long hrtimer_nanosleep(struct timespec *rqtp,
struct timespec __user *rmtp,
const enum hrtimer_mode mode,
const clockid_t clockid);
extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);

extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
struct task_struct *tsk);
4 changes: 4 additions & 0 deletions include/linux/posix-timers.h
Original file line number Diff line number Diff line change
@@ -72,6 +72,7 @@ struct k_clock {
int (*timer_create) (struct k_itimer *timer);
int (*nsleep) (const clockid_t which_clock, int flags,
struct timespec *, struct timespec __user *);
long (*nsleep_restart) (struct restart_block *restart_block);
int (*timer_set) (struct k_itimer * timr, int flags,
struct itimerspec * new_setting,
struct itimerspec * old_setting);
@@ -97,6 +98,7 @@ int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *ts);
int posix_cpu_timer_create(struct k_itimer *timer);
int posix_cpu_nsleep(const clockid_t which_clock, int flags,
struct timespec *rqtp, struct timespec __user *rmtp);
long posix_cpu_nsleep_restart(struct restart_block *restart_block);
int posix_cpu_timer_set(struct k_itimer *timer, int flags,
struct itimerspec *new, struct itimerspec *old);
int posix_cpu_timer_del(struct k_itimer *timer);
@@ -111,4 +113,6 @@ void posix_cpu_timers_exit_group(struct task_struct *task);
void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
cputime_t *newval, cputime_t *oldval);

long clock_nanosleep_restart(struct restart_block *restart_block);

#endif
33 changes: 33 additions & 0 deletions kernel/compat.c
Original file line number Diff line number Diff line change
@@ -22,6 +22,7 @@
#include <linux/security.h>
#include <linux/timex.h>
#include <linux/migrate.h>
#include <linux/posix-timers.h>

#include <asm/uaccess.h>

@@ -601,13 +602,38 @@ long compat_sys_clock_getres(clockid_t which_clock,
return err;
}

static long compat_clock_nanosleep_restart(struct restart_block *restart)
{
long err;
mm_segment_t oldfs;
struct timespec tu;
struct compat_timespec *rmtp = (struct compat_timespec *)(restart->arg1);

restart->arg1 = (unsigned long) &tu;
oldfs = get_fs();
set_fs(KERNEL_DS);
err = clock_nanosleep_restart(restart);
set_fs(oldfs);

if ((err == -ERESTART_RESTARTBLOCK) && rmtp &&
put_compat_timespec(&tu, rmtp))
return -EFAULT;

if (err == -ERESTART_RESTARTBLOCK) {
restart->fn = compat_clock_nanosleep_restart;
restart->arg1 = (unsigned long) rmtp;
}
return err;
}

long compat_sys_clock_nanosleep(clockid_t which_clock, int flags,
struct compat_timespec __user *rqtp,
struct compat_timespec __user *rmtp)
{
long err;
mm_segment_t oldfs;
struct timespec in, out;
struct restart_block *restart;

if (get_compat_timespec(&in, rqtp))
return -EFAULT;
@@ -618,9 +644,16 @@ long compat_sys_clock_nanosleep(clockid_t which_clock, int flags,
(struct timespec __user *) &in,
(struct timespec __user *) &out);
set_fs(oldfs);

if ((err == -ERESTART_RESTARTBLOCK) && rmtp &&
put_compat_timespec(&out, rmtp))
return -EFAULT;

if (err == -ERESTART_RESTARTBLOCK) {
restart = &current_thread_info()->restart_block;
restart->fn = compat_clock_nanosleep_restart;
restart->arg1 = (unsigned long) rmtp;
}
return err;
}

20 changes: 10 additions & 10 deletions kernel/hrtimer.c
Original file line number Diff line number Diff line change
@@ -693,7 +693,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
return t->task == NULL;
}

static long __sched nanosleep_restart(struct restart_block *restart)
long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
{
struct hrtimer_sleeper t;
struct timespec __user *rmtp;
@@ -702,13 +702,13 @@ static long __sched nanosleep_restart(struct restart_block *restart)

restart->fn = do_no_restart_syscall;

hrtimer_init(&t.timer, restart->arg3, HRTIMER_ABS);
t.timer.expires.tv64 = ((u64)restart->arg1 << 32) | (u64) restart->arg0;
hrtimer_init(&t.timer, restart->arg0, HRTIMER_ABS);
t.timer.expires.tv64 = ((u64)restart->arg3 << 32) | (u64) restart->arg2;

if (do_nanosleep(&t, HRTIMER_ABS))
return 0;

rmtp = (struct timespec __user *) restart->arg2;
rmtp = (struct timespec __user *) restart->arg1;
if (rmtp) {
time = ktime_sub(t.timer.expires, t.timer.base->get_time());
if (time.tv64 <= 0)
@@ -718,7 +718,7 @@ static long __sched nanosleep_restart(struct restart_block *restart)
return -EFAULT;
}

restart->fn = nanosleep_restart;
restart->fn = hrtimer_nanosleep_restart;

/* The other values in restart are already filled in */
return -ERESTART_RESTARTBLOCK;
@@ -751,11 +751,11 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
}

restart = &current_thread_info()->restart_block;
restart->fn = nanosleep_restart;
restart->arg0 = t.timer.expires.tv64 & 0xFFFFFFFF;
restart->arg1 = t.timer.expires.tv64 >> 32;
restart->arg2 = (unsigned long) rmtp;
restart->arg3 = (unsigned long) t.timer.base->index;
restart->fn = hrtimer_nanosleep_restart;
restart->arg0 = (unsigned long) t.timer.base->index;
restart->arg1 = (unsigned long) rmtp;
restart->arg2 = t.timer.expires.tv64 & 0xFFFFFFFF;
restart->arg3 = t.timer.expires.tv64 >> 32;

return -ERESTART_RESTARTBLOCK;
}
17 changes: 12 additions & 5 deletions kernel/posix-cpu-timers.c
Original file line number Diff line number Diff line change
@@ -1393,8 +1393,6 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
}
}

static long posix_cpu_clock_nanosleep_restart(struct restart_block *);

int posix_cpu_nsleep(const clockid_t which_clock, int flags,
struct timespec *rqtp, struct timespec __user *rmtp)
{
@@ -1471,7 +1469,7 @@ int posix_cpu_nsleep(const clockid_t which_clock, int flags,
copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
return -EFAULT;

restart_block->fn = posix_cpu_clock_nanosleep_restart;
restart_block->fn = posix_cpu_nsleep_restart;
/* Caller already set restart_block->arg1 */
restart_block->arg0 = which_clock;
restart_block->arg1 = (unsigned long) rmtp;
@@ -1484,8 +1482,7 @@ int posix_cpu_nsleep(const clockid_t which_clock, int flags,
return error;
}

static long
posix_cpu_clock_nanosleep_restart(struct restart_block *restart_block)
long posix_cpu_nsleep_restart(struct restart_block *restart_block)
{
clockid_t which_clock = restart_block->arg0;
struct timespec __user *rmtp;
@@ -1524,6 +1521,10 @@ static int process_cpu_nsleep(const clockid_t which_clock, int flags,
{
return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
}
static long process_cpu_nsleep_restart(struct restart_block *restart_block)
{
return -EINVAL;
}
static int thread_cpu_clock_getres(const clockid_t which_clock,
struct timespec *tp)
{
@@ -1544,6 +1545,10 @@ static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
{
return -EINVAL;
}
static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
{
return -EINVAL;
}

static __init int init_posix_cpu_timers(void)
{
@@ -1553,13 +1558,15 @@ static __init int init_posix_cpu_timers(void)
.clock_set = do_posix_clock_nosettime,
.timer_create = process_cpu_timer_create,
.nsleep = process_cpu_nsleep,
.nsleep_restart = process_cpu_nsleep_restart,
};
struct k_clock thread = {
.clock_getres = thread_cpu_clock_getres,
.clock_get = thread_cpu_clock_get,
.clock_set = do_posix_clock_nosettime,
.timer_create = thread_cpu_timer_create,
.nsleep = thread_cpu_nsleep,
.nsleep_restart = thread_cpu_nsleep_restart,
};

register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
21 changes: 21 additions & 0 deletions kernel/posix-timers.c
Original file line number Diff line number Diff line change
@@ -973,3 +973,24 @@ sys_clock_nanosleep(const clockid_t which_clock, int flags,
return CLOCK_DISPATCH(which_clock, nsleep,
(which_clock, flags, &t, rmtp));
}

/*
* nanosleep_restart for monotonic and realtime clocks
*/
static int common_nsleep_restart(struct restart_block *restart_block)
{
return hrtimer_nanosleep_restart(restart_block);
}

/*
* This will restart clock_nanosleep. This is required only by
* compat_clock_nanosleep_restart for now.
*/
long
clock_nanosleep_restart(struct restart_block *restart_block)
{
clockid_t which_clock = restart_block->arg0;

return CLOCK_DISPATCH(which_clock, nsleep_restart,
(restart_block));
}

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