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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-06-29 12:55:21 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-08-17 08:08:57 -0700
commit8083f29349372d5b949dc022ae9a981edc89ac41 (patch)
tree17c9a7c7256bf37d7e55d9b12c9b4a3c2c4176f0 /kernel/exit.c
parentdec13c42d21a96adc5d0d25510d0b59775dfd2ec (diff)
downloadlinux-8083f29349372d5b949dc022ae9a981edc89ac41.tar.gz
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@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index c5548faa9f37..abfbcf66e5c0 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",