xen: prepare tmem shim to handle frontswap

Provide the shim code for frontswap for Xen tmem even if the
frontswap patchset is not present yet.  (The egg is before
the chicken.)

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Konrad Wilk <konrad.wilk@oracle.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index a59638b37c1a..be8732c32185 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -105,4 +105,11 @@ config SWIOTLB_XEN
         depends on PCI
         select SWIOTLB
 
+config XEN_TMEM
+        bool
+        default y if (CLEANCACHE || FRONTSWAP)
+        help
+          Shim to interface in-kernel Transcendent Memory hooks
+          (e.g. cleancache and frontswap) to Xen tmem hypercalls.
+
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