On Tue, Nov 20, 2018 at 10:34:18PM +0800, Gao Xiang wrote:
> It's better to use atomic_cond_read_relaxed, which is implemented
> in hardware instructions to monitor a variable changes currently
> for ARM64, instead of open-coded busy waiting.
>
> Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
> Signed-off-by: Gao Xiang <gaoxiang25@xxxxxxxxxx>
> ---
> drivers/staging/erofs/internal.h | 30 ++++++++++++++++++------------
> 1 file changed, 18 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
> index 89dbd0888e53..eb80ba44d072 100644
> --- a/drivers/staging/erofs/internal.h
> +++ b/drivers/staging/erofs/internal.h
> @@ -221,23 +221,29 @@ static inline void erofs_workgroup_unfreeze(
> preempt_enable();
> }
>
> +#if defined(CONFIG_SMP)
> +static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
> +{
> + return atomic_cond_read_relaxed(&grp->refcount,
> + VAL != EROFS_LOCKED_MAGIC);
> +}
> +#else
> +static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
> +{
> + int v = atomic_read(&grp->refcount);
Again, why not use the refcount api instead of doing this yourself?
thanks,
greg k-h
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