Add mutex_lock_killable

Similar to mutex_lock_interruptible, it can be interrupted by a fatal
signal only.

Signed-off-by: Liam R. Howlett <howlett@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>

1 files changed, 33 insertions, 3 deletions

diff --git a/kernel/mutex.c b/kernel/mutex.c
index d7fe50cc556f..d9ec9b666250 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -166,9 +166,12 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
                  * got a signal? (This code gets eliminated in the
                  * TASK_UNINTERRUPTIBLE case.)
                  */
-                if (unlikely(state == TASK_INTERRUPTIBLE &&
-                                                signal_pending(task))) {
-                        mutex_remove_waiter(lock, &waiter, task_thread_info(task));
+                if (unlikely((state == TASK_INTERRUPTIBLE &&
+                                        signal_pending(task)) ||
+                              (state == TASK_KILLABLE &&
+                                        fatal_signal_pending(task)))) {
+                        mutex_remove_waiter(lock, &waiter,
+                                            task_thread_info(task));
                         mutex_release(&lock->dep_map, 1, ip);
                         spin_unlock_mutex(&lock->wait_lock, flags);
 
@@ -211,6 +214,14 @@ mutex_lock_nested(struct mutex *lock, unsigned int subclass)
 EXPORT_SYMBOL_GPL(mutex_lock_nested);
 
 int __sched
+mutex_lock_killable_nested(struct mutex *lock, unsigned int subclass)
+{
+        might_sleep();
+        return __mutex_lock_common(lock, TASK_KILLABLE, subclass, _RET_IP_);
+}
+EXPORT_SYMBOL_GPL(mutex_lock_killable_nested);
+
+int __sched
 mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
 {
         might_sleep();
@@ -272,6 +283,9 @@ __mutex_unlock_slowpath(atomic_t *lock_count)
  * mutex_lock_interruptible() and mutex_trylock().
  */
 static int fastcall noinline __sched
+__mutex_lock_killable_slowpath(atomic_t *lock_count);
+
+static noinline int fastcall __sched
 __mutex_lock_interruptible_slowpath(atomic_t *lock_count);
 
 /***
@@ -294,6 +308,14 @@ int fastcall __sched mutex_lock_interruptible(struct mutex *lock)
 
 EXPORT_SYMBOL(mutex_lock_interruptible);
 
+int fastcall __sched mutex_lock_killable(struct mutex *lock)
+{
+        might_sleep();
+        return __mutex_fastpath_lock_retval
+                        (&lock->count, __mutex_lock_killable_slowpath);
+}
+EXPORT_SYMBOL(mutex_lock_killable);
+
 static void fastcall noinline __sched
 __mutex_lock_slowpath(atomic_t *lock_count)
 {
@@ -303,6 +325,14 @@ __mutex_lock_slowpath(atomic_t *lock_count)
 }
 
 static int fastcall noinline __sched
+__mutex_lock_killable_slowpath(atomic_t *lock_count)
+{
+        struct mutex *lock = container_of(lock_count, struct mutex, count);
+
+        return __mutex_lock_common(lock, TASK_KILLABLE, 0, _RET_IP_);
+}
+
+static noinline int fastcall __sched
 __mutex_lock_interruptible_slowpath(atomic_t *lock_count)
 {
         struct mutex *lock = container_of(lock_count, struct mutex, count);