drivers/block/pmem: Map NVDIMM in Write-Through mode

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@hp.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Elliott@hp.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arnd@arndb.de
Cc: hch@lst.de
Cc: hmh@hmh.eng.br
Cc: jgross@suse.com
Cc: konrad.wilk@oracle.com
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-nvdimm@lists.01.org
Cc: stefan.bader@canonical.com
Cc: yigal@plexistor.com
Link: http://lkml.kernel.org/r/1433436928-31903-14-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c
index eabf4a8..095dfaa 100644 (file)
--- 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;