device-dax, tools/testing/nvdimm: enable device-dax with mock resources

Provide a replacement pgoff_to_phys() that translates an nfit_test
resource (allocated by vmalloc()) to a pfn.

Signed-off-by: Dave Jiang <[e-mail]>
Reviewed-by: Johannes Thumshirn <[e-mail]>
Signed-off-by: Dan Williams <[e-mail]>

drivers/dax/dax-private.h

···
+/*
+ * Copyright(c) 2016 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#ifndef __DAX_PRIVATE_H__
+#define __DAX_PRIVATE_H__
+
+#include <linux/device.h>
+#include <linux/cdev.h>
+
+/**
+ * struct dax_region - mapping infrastructure for dax devices
+ * @id: kernel-wide unique region for a memory range
+ * @base: linear address corresponding to @res
+ * @kref: to pin while other agents have a need to do lookups
+ * @dev: parent device backing this region
+ * @align: allocation and mapping alignment for child dax devices
+ * @res: physical address range of the region
+ * @pfn_flags: identify whether the pfns are paged back or not
+ */
+struct dax_region {
+	int id;
+	struct ida ida;
+	void *base;
+	struct kref kref;
+	struct device *dev;
+	unsigned int align;
+	struct resource res;
+	unsigned long pfn_flags;
+};
+
+/**
+ * struct dax_dev - subdivision of a dax region
+ * @region - parent region
+ * @inode - inode
+ * @dev - device backing the character device
+ * @cdev - core chardev data
+ * @alive - !alive + srcu grace period == no new mappings can be established
+ * @id - child id in the region
+ * @num_resources - number of physical address extents in this device
+ * @res - array of physical address ranges
+ */
+struct dax_dev {
+	struct dax_region *region;
+	struct inode *inode;
+	struct device dev;
+	struct cdev cdev;
+	bool alive;
+	int id;
+	int num_resources;
+	struct resource res[0];
+};
+#endif

drivers/dax/dax.c

···
 #include <linux/dax.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
+#include "dax-private.h"
 #include "dax.h"
 
 static dev_t dax_devt;
···
 static struct kmem_cache *dax_cache __read_mostly;
 static struct super_block *dax_superblock __read_mostly;
 MODULE_PARM_DESC(nr_dax, "max number of device-dax instances");
-
-/**
- * struct dax_region - mapping infrastructure for dax devices
- * @id: kernel-wide unique region for a memory range
- * @base: linear address corresponding to @res
- * @kref: to pin while other agents have a need to do lookups
- * @dev: parent device backing this region
- * @align: allocation and mapping alignment for child dax devices
- * @res: physical address range of the region
- * @pfn_flags: identify whether the pfns are paged back or not
- */
-struct dax_region {
-	int id;
-	struct ida ida;
-	void *base;
-	struct kref kref;
-	struct device *dev;
-	unsigned int align;
-	struct resource res;
-	unsigned long pfn_flags;
-};
-
-/**
- * struct dax_dev - subdivision of a dax region
- * @region - parent region
- * @dev - device backing the character device
- * @cdev - core chardev data
- * @alive - !alive + srcu grace period == no new mappings can be established
- * @id - child id in the region
- * @num_resources - number of physical address extents in this device
- * @res - array of physical address ranges
- */
-struct dax_dev {
-	struct dax_region *region;
-	struct inode *inode;
-	struct device dev;
-	struct cdev cdev;
-	bool alive;
-	int id;
-	int num_resources;
-	struct resource res[0];
-};
 
 static ssize_t id_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
···
 	return 0;
 }
 
-static phys_addr_t pgoff_to_phys(struct dax_dev *dax_dev, pgoff_t pgoff,
+/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
+__weak phys_addr_t dax_pgoff_to_phys(struct dax_dev *dax_dev, pgoff_t pgoff,
 		unsigned long size)
 {
 	struct resource *res;
···
 	if (fault_size != dax_region->align)
 		return VM_FAULT_SIGBUS;
 
-	phys = pgoff_to_phys(dax_dev, vmf->pgoff, PAGE_SIZE);
+	phys = dax_pgoff_to_phys(dax_dev, vmf->pgoff, PAGE_SIZE);
 	if (phys == -1) {
 		dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
 				vmf->pgoff);
···
 		return VM_FAULT_SIGBUS;
 
 	pgoff = linear_page_index(vmf->vma, pmd_addr);
-	phys = pgoff_to_phys(dax_dev, pgoff, PMD_SIZE);
+	phys = dax_pgoff_to_phys(dax_dev, pgoff, PMD_SIZE);
 	if (phys == -1) {
 		dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
 				pgoff);
···
 		return VM_FAULT_SIGBUS;
 
 	pgoff = linear_page_index(vmf->vma, pud_addr);
-	phys = pgoff_to_phys(dax_dev, pgoff, PUD_SIZE);
+	phys = dax_pgoff_to_phys(dax_dev, pgoff, PUD_SIZE);
 	if (phys == -1) {
 		dev_dbg(dev, "%s: pgoff_to_phys(%#lx) failed\n", __func__,
 				pgoff);

tools/testing/nvdimm/Kbuild

···
 obj-$(CONFIG_ND_BLK) += nd_blk.o
 obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o
 obj-$(CONFIG_ACPI_NFIT) += nfit.o
-obj-$(CONFIG_DEV_DAX) += dax.o
+obj-$(CONFIG_DEV_DAX) += dax.o dax-dev.o
 obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o
 
 nfit-y := $(ACPI_SRC)/core.o
···
 nd_e820-y += config_check.o
 
 dax-y := $(DAX_SRC)/dax.o
+dax-y += dax-dev.o
 dax-y += config_check.o
 
 dax_pmem-y := $(DAX_SRC)/pmem.o

tools/testing/nvdimm/dax-dev.c

···
+/*
+ * Copyright (c) 2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+#include "test/nfit_test.h"
+#include <linux/mm.h>
+#include "../../../drivers/dax/dax-private.h"
+
+phys_addr_t dax_pgoff_to_phys(struct dax_dev *dax_dev, pgoff_t pgoff,
+		unsigned long size)
+{
+	struct resource *res;
+	phys_addr_t addr;
+	int i;
+
+	for (i = 0; i < dax_dev->num_resources; i++) {
+		res = &dax_dev->res[i];
+		addr = pgoff * PAGE_SIZE + res->start;
+		if (addr >= res->start && addr <= res->end)
+			break;
+		pgoff -= PHYS_PFN(resource_size(res));
+	}
+
+	if (i < dax_dev->num_resources) {
+		res = &dax_dev->res[i];
+		if (addr + size - 1 <= res->end) {
+			if (get_nfit_res(addr)) {
+				struct page *page;
+
+				if (dax_dev->region->align > PAGE_SIZE)
+					return -1;
+
+				page = vmalloc_to_page((void *)addr);
+				return PFN_PHYS(page_to_pfn(page));
+			} else
+				return addr;
+		}
+	}
+
+	return -1;
+}