[PATCH V2] scsi: mpt3sas: remove redundant wmb
Martin K. Petersen
martin.petersen at oracle.com
Wed Apr 19 22:28:30 EDT 2017
Sinan Kaya <okaya at codeaurora.org> 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
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