[Bluetooth] Add open and close callbacks for HID device

[pandora-kernel.git] / kernel / posix-cpu-timers.c

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 479b16b..657f776 100644 (file)
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -87,6 +87,19 @@ static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
        return a;
 }
 
+/*
+ * Divide and limit the result to res >= 1
+ *
+ * This is necessary to prevent signal delivery starvation, when the result of
+ * the division would be rounded down to 0.
+ */
+static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
+{
+       cputime_t res = cputime_div(time, div);
+
+       return max_t(cputime_t, res, 1);
+}
+
 /*
  * Update expiry time from increment, and increase overrun count,
  * given the current clock sample.
@@ -291,7 +304,7 @@ int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
                 * should be able to see it.
                 */
                struct task_struct *p;
-               read_lock(&tasklist_lock);
+               rcu_read_lock();
                p = find_task_by_pid(pid);
                if (p) {
                        if (CPUCLOCK_PERTHREAD(which_clock)) {
@@ -299,12 +312,17 @@ int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
                                        error = cpu_clock_sample(which_clock,
                                                                 p, &rtn);
                                }
-                       } else if (p->tgid == pid && p->signal) {
-                               error = cpu_clock_sample_group(which_clock,
-                                                              p, &rtn);
+                       } else {
+                               read_lock(&tasklist_lock);
+                               if (p->tgid == pid && p->signal) {
+                                       error =
+                                           cpu_clock_sample_group(which_clock,
+                                                                  p, &rtn);
+                               }
+                               read_unlock(&tasklist_lock);
                        }
                }
-               read_unlock(&tasklist_lock);
+               rcu_read_unlock();
        }
 
        if (error)
@@ -483,8 +501,8 @@ static void process_timer_rebalance(struct task_struct *p,
                BUG();
                break;
        case CPUCLOCK_PROF:
-               left = cputime_div(cputime_sub(expires.cpu, val.cpu),
-                                  nthreads);
+               left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
+                                      nthreads);
                do {
                        if (likely(!(t->flags & PF_EXITING))) {
                                ticks = cputime_add(prof_ticks(t), left);
@@ -498,8 +516,8 @@ static void process_timer_rebalance(struct task_struct *p,
                } while (t != p);
                break;
        case CPUCLOCK_VIRT:
-               left = cputime_div(cputime_sub(expires.cpu, val.cpu),
-                                  nthreads);
+               left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
+                                      nthreads);
                do {
                        if (likely(!(t->flags & PF_EXITING))) {
                                ticks = cputime_add(virt_ticks(t), left);
@@ -515,6 +533,7 @@ static void process_timer_rebalance(struct task_struct *p,
        case CPUCLOCK_SCHED:
                nsleft = expires.sched - val.sched;
                do_div(nsleft, nthreads);
+               nsleft = max_t(unsigned long long, nsleft, 1);
                do {
                        if (likely(!(t->flags & PF_EXITING))) {
                                ns = t->sched_time + nsleft;
@@ -1159,12 +1178,13 @@ static void check_process_timers(struct task_struct *tsk,
 
                prof_left = cputime_sub(prof_expires, utime);
                prof_left = cputime_sub(prof_left, stime);
-               prof_left = cputime_div(prof_left, nthreads);
+               prof_left = cputime_div_non_zero(prof_left, nthreads);
                virt_left = cputime_sub(virt_expires, utime);
-               virt_left = cputime_div(virt_left, nthreads);
+               virt_left = cputime_div_non_zero(virt_left, nthreads);
                if (sched_expires) {
                        sched_left = sched_expires - sched_time;
                        do_div(sched_left, nthreads);
+                       sched_left = max_t(unsigned long long, sched_left, 1);
                } else {
                        sched_left = 0;
                }