Re: [PATCH V2] scsi: mpt3sas: remove redundant wmb

[Martin K. Petersen]

Sinan Kaya <okaya@xxxxxxxxxxxxxx> writes:

> Due to relaxed ordering requirements on multiple architectures,
> drivers are required to use wmb/rmb/mb combinations when they need to
> guarantee observability between the memory and the HW.
>
> The mpt3sas driver is already using wmb() for this purpose.  However,
> it issues a writel following wmb(). writel() function on arm/arm64
> arhictectures have an embedded wmb() call inside.
>
> This results in unnecessary performance loss and code duplication.
>
> writel already guarantees ordering for both cpu and bus. we don't need
> additional wmb()

Broadcom folks, please review!

-- 
Martin K. Petersen	Oracle Linux Engineering