From mboxrd@z Thu Jan 1 00:00:00 1970 From: martin.petersen@oracle.com (Martin K. Petersen) Date: Wed, 19 Apr 2017 22:28:30 -0400 Subject: [PATCH V2] scsi: mpt3sas: remove redundant wmb In-Reply-To: <1491591978-17880-1-git-send-email-okaya@codeaurora.org> (Sinan Kaya's message of "Fri, 7 Apr 2017 15:06:18 -0400") References: <1491591978-17880-1-git-send-email-okaya@codeaurora.org> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Sinan Kaya 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