[SCSI] scsi: Added support for adapter and firmware reset
[linux-2.6.git] / kernel / itimer.c
index 1dc988e..d802883 100644 (file)
@@ -7,90 +7,92 @@
 /* These are all the functions necessary to implement itimers */
 
 #include <linux/mm.h>
-#include <linux/smp_lock.h>
 #include <linux/interrupt.h>
 #include <linux/syscalls.h>
 #include <linux/time.h>
 #include <linux/posix-timers.h>
+#include <linux/hrtimer.h>
+#include <trace/events/timer.h>
 
 #include <asm/uaccess.h>
 
-static unsigned long it_real_value(struct signal_struct *sig)
+/**
+ * itimer_get_remtime - get remaining time for the timer
+ *
+ * @timer: the timer to read
+ *
+ * Returns the delta between the expiry time and now, which can be
+ * less than zero or 1usec for an pending expired timer
+ */
+static struct timeval itimer_get_remtime(struct hrtimer *timer)
+{
+       ktime_t rem = hrtimer_get_remaining(timer);
+
+       /*
+        * Racy but safe: if the itimer expires after the above
+        * hrtimer_get_remtime() call but before this condition
+        * then we return 0 - which is correct.
+        */
+       if (hrtimer_active(timer)) {
+               if (rem.tv64 <= 0)
+                       rem.tv64 = NSEC_PER_USEC;
+       } else
+               rem.tv64 = 0;
+
+       return ktime_to_timeval(rem);
+}
+
+static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
+                          struct itimerval *const value)
 {
-       unsigned long val = 0;
-       if (timer_pending(&sig->real_timer)) {
-               val = sig->real_timer.expires - jiffies;
+       cputime_t cval, cinterval;
+       struct cpu_itimer *it = &tsk->signal->it[clock_id];
+
+       spin_lock_irq(&tsk->sighand->siglock);
+
+       cval = it->expires;
+       cinterval = it->incr;
+       if (!cputime_eq(cval, cputime_zero)) {
+               struct task_cputime cputime;
+               cputime_t t;
+
+               thread_group_cputimer(tsk, &cputime);
+               if (clock_id == CPUCLOCK_PROF)
+                       t = cputime_add(cputime.utime, cputime.stime);
+               else
+                       /* CPUCLOCK_VIRT */
+                       t = cputime.utime;
 
-               /* look out for negative/zero itimer.. */
-               if ((long) val <= 0)
-                       val = 1;
+               if (cputime_le(cval, t))
+                       /* about to fire */
+                       cval = cputime_one_jiffy;
+               else
+                       cval = cputime_sub(cval, t);
        }
-       return val;
+
+       spin_unlock_irq(&tsk->sighand->siglock);
+
+       cputime_to_timeval(cval, &value->it_value);
+       cputime_to_timeval(cinterval, &value->it_interval);
 }
 
 int do_getitimer(int which, struct itimerval *value)
 {
        struct task_struct *tsk = current;
-       unsigned long interval, val;
-       cputime_t cinterval, cval;
 
        switch (which) {
        case ITIMER_REAL:
                spin_lock_irq(&tsk->sighand->siglock);
-               interval = tsk->signal->it_real_incr;
-               val = it_real_value(tsk->signal);
+               value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
+               value->it_interval =
+                       ktime_to_timeval(tsk->signal->it_real_incr);
                spin_unlock_irq(&tsk->sighand->siglock);
-               jiffies_to_timeval(val, &value->it_value);
-               jiffies_to_timeval(interval, &value->it_interval);
                break;
        case ITIMER_VIRTUAL:
-               read_lock(&tasklist_lock);
-               spin_lock_irq(&tsk->sighand->siglock);
-               cval = tsk->signal->it_virt_expires;
-               cinterval = tsk->signal->it_virt_incr;
-               if (!cputime_eq(cval, cputime_zero)) {
-                       struct task_struct *t = tsk;
-                       cputime_t utime = tsk->signal->utime;
-                       do {
-                               utime = cputime_add(utime, t->utime);
-                               t = next_thread(t);
-                       } while (t != tsk);
-                       if (cputime_le(cval, utime)) { /* about to fire */
-                               cval = jiffies_to_cputime(1);
-                       } else {
-                               cval = cputime_sub(cval, utime);
-                       }
-               }
-               spin_unlock_irq(&tsk->sighand->siglock);
-               read_unlock(&tasklist_lock);
-               cputime_to_timeval(cval, &value->it_value);
-               cputime_to_timeval(cinterval, &value->it_interval);
+               get_cpu_itimer(tsk, CPUCLOCK_VIRT, value);
                break;
        case ITIMER_PROF:
-               read_lock(&tasklist_lock);
-               spin_lock_irq(&tsk->sighand->siglock);
-               cval = tsk->signal->it_prof_expires;
-               cinterval = tsk->signal->it_prof_incr;
-               if (!cputime_eq(cval, cputime_zero)) {
-                       struct task_struct *t = tsk;
-                       cputime_t ptime = cputime_add(tsk->signal->utime,
-                                                     tsk->signal->stime);
-                       do {
-                               ptime = cputime_add(ptime,
-                                                   cputime_add(t->utime,
-                                                               t->stime));
-                               t = next_thread(t);
-                       } while (t != tsk);
-                       if (cputime_le(cval, ptime)) { /* about to fire */
-                               cval = jiffies_to_cputime(1);
-                       } else {
-                               cval = cputime_sub(cval, ptime);
-                       }
-               }
-               spin_unlock_irq(&tsk->sighand->siglock);
-               read_unlock(&tasklist_lock);
-               cputime_to_timeval(cval, &value->it_value);
-               cputime_to_timeval(cinterval, &value->it_interval);
+               get_cpu_itimer(tsk, CPUCLOCK_PROF, value);
                break;
        default:
                return(-EINVAL);
@@ -98,7 +100,7 @@ int do_getitimer(int which, struct itimerval *value)
        return 0;
 }
 
-asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
+SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
 {
        int error = -EFAULT;
        struct itimerval get_buffer;
@@ -112,109 +114,124 @@ asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
        return error;
 }
 
+
 /*
- * Called with P->sighand->siglock held and P->signal->real_timer inactive.
- * If interval is nonzero, arm the timer for interval ticks from now.
+ * The timer is automagically restarted, when interval != 0
  */
-static inline void it_real_arm(struct task_struct *p, unsigned long interval)
+enum hrtimer_restart it_real_fn(struct hrtimer *timer)
 {
-       p->signal->it_real_value = interval; /* XXX unnecessary field?? */
-       if (interval == 0)
-               return;
-       if (interval > (unsigned long) LONG_MAX)
-               interval = LONG_MAX;
-       /* the "+ 1" below makes sure that the timer doesn't go off before
-        * the interval requested. This could happen if
-        * time requested % (usecs per jiffy) is more than the usecs left
-        * in the current jiffy */
-       p->signal->real_timer.expires = jiffies + interval + 1;
-       add_timer(&p->signal->real_timer);
+       struct signal_struct *sig =
+               container_of(timer, struct signal_struct, real_timer);
+
+       trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0);
+       kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
+
+       return HRTIMER_NORESTART;
 }
 
-void it_real_fn(unsigned long __data)
+static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns)
 {
-       struct task_struct * p = (struct task_struct *) __data;
+       struct timespec ts;
+       s64 cpu_ns;
 
-       send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p);
+       cputime_to_timespec(ct, &ts);
+       cpu_ns = timespec_to_ns(&ts);
 
-       /*
-        * Now restart the timer if necessary.  We don't need any locking
-        * here because do_setitimer makes sure we have finished running
-        * before it touches anything.
-        */
-       it_real_arm(p, p->signal->it_real_incr);
+       return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns;
+}
+
+static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
+                          const struct itimerval *const value,
+                          struct itimerval *const ovalue)
+{
+       cputime_t cval, nval, cinterval, ninterval;
+       s64 ns_ninterval, ns_nval;
+       u32 error, incr_error;
+       struct cpu_itimer *it = &tsk->signal->it[clock_id];
+
+       nval = timeval_to_cputime(&value->it_value);
+       ns_nval = timeval_to_ns(&value->it_value);
+       ninterval = timeval_to_cputime(&value->it_interval);
+       ns_ninterval = timeval_to_ns(&value->it_interval);
+
+       error = cputime_sub_ns(nval, ns_nval);
+       incr_error = cputime_sub_ns(ninterval, ns_ninterval);
+
+       spin_lock_irq(&tsk->sighand->siglock);
+
+       cval = it->expires;
+       cinterval = it->incr;
+       if (!cputime_eq(cval, cputime_zero) ||
+           !cputime_eq(nval, cputime_zero)) {
+               if (cputime_gt(nval, cputime_zero))
+                       nval = cputime_add(nval, cputime_one_jiffy);
+               set_process_cpu_timer(tsk, clock_id, &nval, &cval);
+       }
+       it->expires = nval;
+       it->incr = ninterval;
+       it->error = error;
+       it->incr_error = incr_error;
+       trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
+                          ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
+
+       spin_unlock_irq(&tsk->sighand->siglock);
+
+       if (ovalue) {
+               cputime_to_timeval(cval, &ovalue->it_value);
+               cputime_to_timeval(cinterval, &ovalue->it_interval);
+       }
 }
 
+/*
+ * Returns true if the timeval is in canonical form
+ */
+#define timeval_valid(t) \
+       (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
+
 int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
 {
        struct task_struct *tsk = current;
-       unsigned long val, interval;
-       cputime_t cval, cinterval, nval, ninterval;
+       struct hrtimer *timer;
+       ktime_t expires;
+
+       /*
+        * Validate the timevals in value.
+        */
+       if (!timeval_valid(&value->it_value) ||
+           !timeval_valid(&value->it_interval))
+               return -EINVAL;
 
        switch (which) {
        case ITIMER_REAL:
+again:
                spin_lock_irq(&tsk->sighand->siglock);
-               interval = tsk->signal->it_real_incr;
-               val = it_real_value(tsk->signal);
-               if (val)
-                       del_timer_sync(&tsk->signal->real_timer);
-               tsk->signal->it_real_incr =
-                       timeval_to_jiffies(&value->it_interval);
-               it_real_arm(tsk, timeval_to_jiffies(&value->it_value));
-               spin_unlock_irq(&tsk->sighand->siglock);
+               timer = &tsk->signal->real_timer;
                if (ovalue) {
-                       jiffies_to_timeval(val, &ovalue->it_value);
-                       jiffies_to_timeval(interval,
-                                          &ovalue->it_interval);
+                       ovalue->it_value = itimer_get_remtime(timer);
+                       ovalue->it_interval
+                               = ktime_to_timeval(tsk->signal->it_real_incr);
                }
-               break;
-       case ITIMER_VIRTUAL:
-               nval = timeval_to_cputime(&value->it_value);
-               ninterval = timeval_to_cputime(&value->it_interval);
-               read_lock(&tasklist_lock);
-               spin_lock_irq(&tsk->sighand->siglock);
-               cval = tsk->signal->it_virt_expires;
-               cinterval = tsk->signal->it_virt_incr;
-               if (!cputime_eq(cval, cputime_zero) ||
-                   !cputime_eq(nval, cputime_zero)) {
-                       if (cputime_gt(nval, cputime_zero))
-                               nval = cputime_add(nval,
-                                                  jiffies_to_cputime(1));
-                       set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
-                                             &nval, &cval);
+               /* We are sharing ->siglock with it_real_fn() */
+               if (hrtimer_try_to_cancel(timer) < 0) {
+                       spin_unlock_irq(&tsk->sighand->siglock);
+                       goto again;
                }
-               tsk->signal->it_virt_expires = nval;
-               tsk->signal->it_virt_incr = ninterval;
+               expires = timeval_to_ktime(value->it_value);
+               if (expires.tv64 != 0) {
+                       tsk->signal->it_real_incr =
+                               timeval_to_ktime(value->it_interval);
+                       hrtimer_start(timer, expires, HRTIMER_MODE_REL);
+               } else
+                       tsk->signal->it_real_incr.tv64 = 0;
+
+               trace_itimer_state(ITIMER_REAL, value, 0);
                spin_unlock_irq(&tsk->sighand->siglock);
-               read_unlock(&tasklist_lock);
-               if (ovalue) {
-                       cputime_to_timeval(cval, &ovalue->it_value);
-                       cputime_to_timeval(cinterval, &ovalue->it_interval);
-               }
+               break;
+       case ITIMER_VIRTUAL:
+               set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue);
                break;
        case ITIMER_PROF:
-               nval = timeval_to_cputime(&value->it_value);
-               ninterval = timeval_to_cputime(&value->it_interval);
-               read_lock(&tasklist_lock);
-               spin_lock_irq(&tsk->sighand->siglock);
-               cval = tsk->signal->it_prof_expires;
-               cinterval = tsk->signal->it_prof_incr;
-               if (!cputime_eq(cval, cputime_zero) ||
-                   !cputime_eq(nval, cputime_zero)) {
-                       if (cputime_gt(nval, cputime_zero))
-                               nval = cputime_add(nval,
-                                                  jiffies_to_cputime(1));
-                       set_process_cpu_timer(tsk, CPUCLOCK_PROF,
-                                             &nval, &cval);
-               }
-               tsk->signal->it_prof_expires = nval;
-               tsk->signal->it_prof_incr = ninterval;
-               spin_unlock_irq(&tsk->sighand->siglock);
-               read_unlock(&tasklist_lock);
-               if (ovalue) {
-                       cputime_to_timeval(cval, &ovalue->it_value);
-                       cputime_to_timeval(cinterval, &ovalue->it_interval);
-               }
+               set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue);
                break;
        default:
                return -EINVAL;
@@ -222,9 +239,45 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
        return 0;
 }
 
-asmlinkage long sys_setitimer(int which,
-                             struct itimerval __user *value,
-                             struct itimerval __user *ovalue)
+/**
+ * alarm_setitimer - set alarm in seconds
+ *
+ * @seconds:   number of seconds until alarm
+ *             0 disables the alarm
+ *
+ * Returns the remaining time in seconds of a pending timer or 0 when
+ * the timer is not active.
+ *
+ * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
+ * negative timeval settings which would cause immediate expiry.
+ */
+unsigned int alarm_setitimer(unsigned int seconds)
+{
+       struct itimerval it_new, it_old;
+
+#if BITS_PER_LONG < 64
+       if (seconds > INT_MAX)
+               seconds = INT_MAX;
+#endif
+       it_new.it_value.tv_sec = seconds;
+       it_new.it_value.tv_usec = 0;
+       it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
+
+       do_setitimer(ITIMER_REAL, &it_new, &it_old);
+
+       /*
+        * We can't return 0 if we have an alarm pending ...  And we'd
+        * better return too much than too little anyway
+        */
+       if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
+             it_old.it_value.tv_usec >= 500000)
+               it_old.it_value.tv_sec++;
+
+       return it_old.it_value.tv_sec;
+}
+
+SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
+               struct itimerval __user *, ovalue)
 {
        struct itimerval set_buffer, get_buffer;
        int error;
@@ -240,6 +293,6 @@ asmlinkage long sys_setitimer(int which,
                return error;
 
        if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
-               return -EFAULT; 
+               return -EFAULT;
        return 0;
 }