From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 29 May 2017 13:07:46 -0700
Subject: filesystem-dax: convert to dax_flush()
Patch-mainline: v4.13-rc1
Git-commit: 6318770a7d43a4166b6a8e3cef62e4a019d3c95e
References: FATE#323717

Filesystem-DAX flushes caches whenever it writes to the address returned
through dax_direct_access() and when writing back dirty radix entries.
That flushing is only required in the pmem case, so the dax_flush()
helper skips cache management work when the underlying driver does not
specify a flush method.

We still do all the dirty tracking since the radix entry will already be
there for locking purposes. However, the work to clean the entry will be
a nop for some dax drivers.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 fs/dax.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/dax.c
+++ b/fs/dax.c
@@ -784,7 +784,7 @@ static int dax_writeback_one(struct bloc
 	}
 
 	dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn));
-	wb_cache_pmem(kaddr, size);
+	dax_flush(dax_dev, pgoff, kaddr, size);
 	/*
 	 * After we have flushed the cache, we can clear the dirty tag. There
 	 * cannot be new dirty data in the pfn after the flush has completed as