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    [SCSI] ipr: Remove unnecessary memory barriers · a5fb407e
    Brian King 提交于
    The ipr driver added some memory barriers in order to ensure
    a PowerPC sync instruction was executed prior to sending a
    command to the adapter to ensure the command block was
    coherent with respect to the PCI bus's view of memory.
    However, some time ago, the powerpc architecture writel
    macros were changed to include the sync since most drivers
    don't properly handle this. So remove these memory barriers
    since they are not needed and result in executing twice
    as many sync instructions, which has a significant performance
    penalty.
    Signed-off-by: NBrian King <brking@linux.vnet.ibm.com>
    Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>
    a5fb407e
ipr.c 258.2 KB