Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH v3 6/9] ipc: Replace spin_unlock_wait() with lock/unlock pair | Date | Fri, 7 Jul 2017 12:28:23 -0700 |
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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 exit_sem() with spin_lock() followed immediately by spin_unlock(). This should be safe from a performance perspective because exit_sem() is rarely invoked in production.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Will Deacon <will.deacon@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Manfred Spraul <manfred@colorfullife.com> --- ipc/sem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/ipc/sem.c b/ipc/sem.c index 947dc2348271..e88d0749a929 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -2096,7 +2096,8 @@ void exit_sem(struct task_struct *tsk) * possibility where we exit while freeary() didn't * finish unlocking sem_undo_list. */ - spin_unlock_wait(&ulp->lock); + spin_lock(&ulp->lock); + spin_unlock(&ulp->lock); rcu_read_unlock(); break; } -- 2.5.2
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