The intent of the function is to wait for the current locker. Thus, we don't have to worry about potential later lockers, but we also have to ensure that the arch implementation doesn't return a false positive for the current locker.
Signed-off-by: Chris Metcalf <[email protected]> --- On 04/28/2015 12:24 PM, Peter Zijlstra wrote: > I think it must not return before the lock holder that is current at the > time of calling releases. Anything thereafter is indeed fair game as per > your logic above. Great, that seems like a workable definition. How does this modified language seem? With this definition I can actually modify the implementation of tile's arch_raw_spin_unlock_wait() to just read current_ticket once and just wait until it changes (assuming the lock is, in fact, locked). Not sure whose tree this should go through; any takers? include/linux/spinlock.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 3e18379dfa6f..36de5fc86647 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -141,7 +141,8 @@ do { \ #endif /** - * raw_spin_unlock_wait - wait until the spinlock gets unlocked + * raw_spin_unlock_wait - wait until the lock holder that is current at the + * time of calling releases the lock (or return immediately if unlocked). * @lock: the spinlock in question. */ #define raw_spin_unlock_wait(lock) arch_spin_unlock_wait(&(lock)->raw_lock) -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
