Re: [PATCH v7 4/4] qrwlock: Use smp_store_release() in write_unlock()

From: Paul E. McKenney
Date: Tue Dec 17 2013 - 14:24:52 EST


On Fri, Nov 22, 2013 at 02:04:47PM -0500, Waiman Long wrote:
> This patch modifies the queue_write_unlock() function to use the
> new smp_store_release() function in another pending patch. This patch
> should only be merged if the other patch was merged.
>
> Signed-off-by: Waiman Long <Waiman.Long@xxxxxx>

Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>

> ---
> include/asm-generic/qrwlock.h | 4 +---
> 1 files changed, 1 insertions(+), 3 deletions(-)
>
> diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h
> index 335473a..59c5972 100644
> --- a/include/asm-generic/qrwlock.h
> +++ b/include/asm-generic/qrwlock.h
> @@ -176,9 +176,7 @@ static inline void queue_write_unlock(struct qrwlock *lock)
> /*
> * Make sure that none of the critical section will be leaked out.
> */
> - smp_mb__before_clear_bit();
> - ACCESS_ONCE(lock->cnts.writer) = 0;
> - smp_mb__after_clear_bit();
> + smp_store_release(&lock->cnts.writer, 0)
> }
>
> /*
> --
> 1.7.1
>

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