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    Subject[PATCH v12 10/10] drivers/block/pmem: Map NVDIMM with ioremap_wt()
    Date
    The pmem driver maps NVDIMM with ioremap_nocache() as we cannot
    write back the contents of the CPU caches in case of a crash.

    This patch changes to use ioremap_wt(), which provides uncached
    writes but cached reads, for improving read performance.

    Signed-off-by: Toshi Kani <toshi.kani@hp.com>
    Acked-by: Dan Williams <dan.j.williams@intel.com>
    ---
    drivers/block/pmem.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c
    index eabf4a8..095dfaa 100644
    --- a/drivers/block/pmem.c
    +++ b/drivers/block/pmem.c
    @@ -139,11 +139,11 @@ static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
    }

    /*
    - * Map the memory as non-cachable, as we can't write back the contents
    + * Map the memory as write-through, as we can't write back the contents
    * of the CPU caches in case of a crash.
    */
    err = -ENOMEM;
    - pmem->virt_addr = ioremap_nocache(pmem->phys_addr, pmem->size);
    + pmem->virt_addr = ioremap_wt(pmem->phys_addr, pmem->size);
    if (!pmem->virt_addr)
    goto out_release_region;


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