Update from upstream with manual merge of Yasunori Goto's

changes to swiotlb.c made in commit 281dd25cdc0d6903929b79183816d151ea626341
since this file has been moved from arch/ia64/lib/swiotlb.c to
lib/swiotlb.c

Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 14 insertions, 17 deletions

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index ad85d3f0dcc4..b3f3edc475de 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -387,25 +387,19 @@ int posix_cpu_timer_del(struct k_itimer *timer)
         if (unlikely(p == NULL))
                 return 0;
 
+        spin_lock(&p->sighand->siglock);
         if (!list_empty(&timer->it.cpu.entry)) {
-                read_lock(&tasklist_lock);
-                if (unlikely(p->signal == NULL)) {
-                        /*
-                         * We raced with the reaping of the task.
-                         * The deletion should have cleared us off the list.
-                         */
-                        BUG_ON(!list_empty(&timer->it.cpu.entry));
-                } else {
-                        /*
-                         * Take us off the task's timer list.
-                         */
-                        spin_lock(&p->sighand->siglock);
-                        list_del(&timer->it.cpu.entry);
-                        spin_unlock(&p->sighand->siglock);
-                }
-                read_unlock(&tasklist_lock);
+                /*
+                 * Take us off the task's timer list.  We don't need to
+                 * take tasklist_lock and check for the task being reaped.
+                 * If it was reaped, it already called posix_cpu_timers_exit
+                 * and posix_cpu_timers_exit_group to clear all the timers
+                 * that pointed to it.
+                 */
+                list_del(&timer->it.cpu.entry);
+                put_task_struct(p);
         }
-        put_task_struct(p);
+        spin_unlock(&p->sighand->siglock);
 
         return 0;
 }
@@ -424,6 +418,7 @@ static void cleanup_timers(struct list_head *head,
         cputime_t ptime = cputime_add(utime, stime);
 
         list_for_each_entry_safe(timer, next, head, entry) {
+                put_task_struct(timer->task);
                 timer->task = NULL;
                 list_del_init(&timer->entry);
                 if (cputime_lt(timer->expires.cpu, ptime)) {
@@ -436,6 +431,7 @@ static void cleanup_timers(struct list_head *head,
 
         ++head;
         list_for_each_entry_safe(timer, next, head, entry) {
+                put_task_struct(timer->task);
                 timer->task = NULL;
                 list_del_init(&timer->entry);
                 if (cputime_lt(timer->expires.cpu, utime)) {
@@ -448,6 +444,7 @@ static void cleanup_timers(struct list_head *head,
 
         ++head;
         list_for_each_entry_safe(timer, next, head, entry) {
+                put_task_struct(timer->task);
                 timer->task = NULL;
                 list_del_init(&timer->entry);
                 if (timer->expires.sched < sched_time) {