Commit-ID: 8083f29349372d5b949dc022ae9a981edc89ac41
Gitweb: http://git.kernel.org/tip/8083f29349372d5b949dc022ae9a981edc89ac41
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Thu, 29 Jun 2017 12:55:21 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 17 Aug 2017 08:08:57 -0700
exit: Replace spin_unlock_wait() with lock/unlock pair
There is no agreed-upon definition of spin_unlock_wait()'s semantics, and
it appears that all callers could do just as well with a lock/unlock pair.
This commit therefore replaces the spin_unlock_wait() call in do_exit()
with spin_lock() followed immediately by spin_unlock(). This should be
safe from a performance perspective because the lock is a per-task lock,
and this is happening only at task-exit time.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: Andrea Parri <parri.andrea@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
---
kernel/exit.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/exit.c b/kernel/exit.c
index c5548fa..abfbcf6 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -819,7 +819,8 @@ void __noreturn do_exit(long code)
* Ensure that we must observe the pi_state in exit_mm() ->
* mm_release() -> exit_pi_state_list().
*/
- raw_spin_unlock_wait(&tsk->pi_lock);
+ raw_spin_lock_irq(&tsk->pi_lock);
+ raw_spin_unlock_irq(&tsk->pi_lock);
if (unlikely(in_atomic())) {
pr_info("note: %s[%d] exited with preempt_count %d\n",
--
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