[PATCH 13/20] drivers/block/pmem: Map NVDIMM in Write-Through mode

[Borislav Petkov]

From: Toshi Kani <toshi.kani@xxxxxx>

The pmem driver maps NVDIMM uncacheable so that we don't lose data which
hasn't reached non-volatile storage in the case of a crash. Change this
to Write-Through mode which provides uncached writes but cached reads,
thus improving read performance.

Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: arnd@xxxxxxxx
Cc: Elliott@xxxxxx
Cc: hch@xxxxxx
Cc: hmh@xxxxxxxxxx
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: jgross@xxxxxxxx
Cc: konrad.wilk@xxxxxxxxxx
Cc: linux-mm <linux-mm@xxxxxxxxx>
Cc: linux-nvdimm@xxxxxxxxxxxx
Cc: Luis R. Rodriguez <mcgrof@xxxxxxxx>
Cc: stefan.bader@xxxxxxxxxxxxx
Cc: x86-ml <x86@xxxxxxxxxx>
Cc: yigal@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1432739944-22633-13-git-send-email-toshi.kani@xxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
 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 eabf4a8d0085..095dfaadcaa5 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;
 
-- 
2.3.5

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