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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-06-29 12:59:32 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-08-17 08:08:57 -0700 |
| commit | e0892e086aae8d86e33dc8fb87f3d36c901df574 (patch) | |
| tree | 6a480513ccaa1bb3e2427bddf8f452994bc3d901 /ipc | |
| parent | 8083f29349372d5b949dc022ae9a981edc89ac41 (diff) | |
| download | lwn-e0892e086aae8d86e33dc8fb87f3d36c901df574.tar.gz lwn-e0892e086aae8d86e33dc8fb87f3d36c901df574.zip | |
ipc: 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
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>
Diffstat (limited to 'ipc')
| -rw-r--r-- | ipc/sem.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index 9e70cd7a17da..2570830e29fc 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -2091,7 +2091,8 @@ 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; } |