dax: move dax_pgoff_to_phys from [drivers/dax/] device.c to bus.c

This function will be used by both device.c and fsdev.c, but both are
loadable modules. Moving to bus.c puts it in core and makes it available
to both.

No code changes - just relocated.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: John Groves <john@groves.net>
Link: https://patch.msgid.link/0100019d311c90eb-a582ff97-93ba-49f3-8140-6c5c4bf8bc62-000000@email.amazonses.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>

Author: jagalactic

drivers/dax/bus.c

@@ -1417,6 +1417,26 @@ static const struct device_type dev_dax_type = {
 	.groups = dax_attribute_groups,
 };
 
+/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
+__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
+			      unsigned long size)
+{
+	for (int i = 0; i < dev_dax->nr_range; i++) {
+		struct dev_dax_range *dax_range = &dev_dax->ranges[i];
+		struct range *range = &dax_range->range;
+		phys_addr_t phys;
+
+		if (!in_range(pgoff, dax_range->pgoff, PHYS_PFN(range_len(range))))
+			continue;
+		phys = PFN_PHYS(pgoff - dax_range->pgoff) + range->start;
+		if (phys + size - 1 <= range->end)
+			return phys;
+		break;
+	}
+	return -1;
+}
+EXPORT_SYMBOL_GPL(dax_pgoff_to_phys);
+
 static struct dev_dax *__devm_create_dev_dax(struct dev_dax_data *data)
 {
 	struct dax_region *dax_region = data->dax_region;

drivers/dax/device.c

@@ -57,29 +57,6 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
 			   vma->vm_file, func);
 }
 
-/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
-__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
-		unsigned long size)
-{
-	int i;
-
-	for (i = 0; i < dev_dax->nr_range; i++) {
-		struct dev_dax_range *dax_range = &dev_dax->ranges[i];
-		struct range *range = &dax_range->range;
-		unsigned long long pgoff_end;
-		phys_addr_t phys;
-
-		pgoff_end = dax_range->pgoff + PHYS_PFN(range_len(range)) - 1;
-		if (pgoff < dax_range->pgoff || pgoff > pgoff_end)
-			continue;
-		phys = PFN_PHYS(pgoff - dax_range->pgoff) + range->start;
-		if (phys + size - 1 <= range->end)
-			return phys;
-		break;
-	}
-	return -1;
-}
-
 static void dax_set_mapping(struct vm_fault *vmf, unsigned long pfn,
 			      unsigned long fault_size)
 {