Re: [PATCH v7 6/7] bnxt_en: Eliminate duplicate barriers on weakly-ordered archs

From: Michael Chan
Date: Sun Mar 25 2018 - 16:24:21 EST


On Sun, Mar 25, 2018 at 7:39 AM, Sinan Kaya <okaya@xxxxxxxxxxxxxx> wrote:
> Code includes wmb() followed by writel(). writel() already has a barrier on
> some architectures like arm64.
>
> This ends up CPU observing two barriers back to back before executing the
> register write.
>
> Create a new wrapper function with relaxed write operator. Use the new
> wrapper when a write is following a wmb().
>
> Since code already has an explicit barrier call, changing writel() to
> writel_relaxed().
>
> Also add mmiowb() so that write code doesn't move outside of scope.

This line in the patch description is not needed anymore. Other than that,

Acked-by: Michael Chan <michael.chan@xxxxxxxxxxxx>

Thanks.
>
> Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>