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Groups > linux.kernel > #1626923
| From | "Martin K. Petersen" <martin.petersen@oracle.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH V2] scsi: mpt3sas: remove redundant wmb |
| Date | 2017-04-20 04:30 +0200 |
| Message-ID | <tya13-38v-13@gated-at.bofh.it> (permalink) |
| References | <ttHqG-3bW-21@gated-at.bofh.it> |
| Organization | Oracle Corporation |
Sinan Kaya <okaya@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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Re: [PATCH V2] scsi: mpt3sas: remove redundant wmb "Martin K. Petersen" <martin.petersen@oracle.com> - 2017-04-20 04:30 +0200
Re: [PATCH V2] scsi: mpt3sas: remove redundant wmb Sreekanth Reddy <sreekanth.reddy@broadcom.com> - 2017-04-21 10:00 +0200
Re: [PATCH V2] scsi: mpt3sas: remove redundant wmb Sinan Kaya <okaya@codeaurora.org> - 2017-04-21 15:50 +0200
Re: [PATCH V2] scsi: mpt3sas: remove redundant wmb Brian King <brking@linux.vnet.ibm.com> - 2017-04-21 21:10 +0200
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