libnvdimm, pmem: allow nfit_test to override pmem_direct_access()

Currently phys_to_pfn_t() is an exported symbol to allow nfit_test to
override it and indicate that nfit_test-pmem is not device-mapped.  Now,
we want to enable nfit_test to operate without DMA_CMA and the pmem it
provides will no longer be physically contiguous, i.e. won't be capable
of supporting direct_access requests larger than a page.  Make
pmem_direct_access() a weak symbol so that it can be replaced by the
tools/testing/nvdimm/ version, and move phys_to_pfn_t() to a static
inline now that it no longer needs to be overridden.

Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

2 files changed, 27 insertions, 15 deletions

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index ba253df6233f..b6fcb97a601c 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -29,23 +29,10 @@
 #include <linux/slab.h>
 #include <linux/pmem.h>
 #include <linux/nd.h>
+#include "pmem.h"
 #include "pfn.h"
 #include "nd.h"
 
-struct pmem_device {
-        /* One contiguous memory region per device */
-        phys_addr_t             phys_addr;
-        /* when non-zero this device is hosting a 'pfn' instance */
-        phys_addr_t             data_offset;
-        u64                     pfn_flags;
-        void __pmem             *virt_addr;
-        /* immutable base size of the namespace */
-        size_t                  size;
-        /* trim size when namespace capacity has been section aligned */
-        u32                     pfn_pad;
-        struct badblocks        bb;
-};
-
 static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
                 unsigned int len)
 {
@@ -163,7 +150,8 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
         return rc;
 }
 
-static long pmem_direct_access(struct block_device *bdev, sector_t sector,
+/* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
+__weak long pmem_direct_access(struct block_device *bdev, sector_t sector,
                       void __pmem **kaddr, pfn_t *pfn, long size)
 {
         struct pmem_device *pmem = bdev->bd_queue->queuedata;
diff --git a/drivers/nvdimm/pmem.h b/drivers/nvdimm/pmem.h
new file mode 100644
index 000000000000..c48d4e3aa346
--- /dev/null
+++ b/drivers/nvdimm/pmem.h
@@ -0,0 +1,24 @@
+#ifndef __NVDIMM_PMEM_H__
+#define __NVDIMM_PMEM_H__
+#include <linux/badblocks.h>
+#include <linux/types.h>
+#include <linux/pfn_t.h>
+#include <linux/fs.h>
+
+long pmem_direct_access(struct block_device *bdev, sector_t sector,
+                      void __pmem **kaddr, pfn_t *pfn, long size);
+/* this definition is in it's own header for tools/testing/nvdimm to consume */
+struct pmem_device {
+        /* One contiguous memory region per device */
+        phys_addr_t             phys_addr;
+        /* when non-zero this device is hosting a 'pfn' instance */
+        phys_addr_t             data_offset;
+        u64                     pfn_flags;
+        void __pmem             *virt_addr;
+        /* immutable base size of the namespace */
+        size_t                  size;
+        /* trim size when namespace capacity has been section aligned */
+        u32                     pfn_pad;
+        struct badblocks        bb;
+};
+#endif /* __NVDIMM_PMEM_H__ */