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>

tools/testing/nvdimm/Kbuild

@@ -11,12 +11,12 @@ ldflags-y += --wrap=__devm_release_region
 ldflags-y += --wrap=__request_region
 ldflags-y += --wrap=__release_region
 ldflags-y += --wrap=devm_memremap_pages
-ldflags-y += --wrap=phys_to_pfn_t
 
 DRIVERS := ../../../drivers
 NVDIMM_SRC := $(DRIVERS)/nvdimm
 ACPI_SRC := $(DRIVERS)/acpi
 DAX_SRC := $(DRIVERS)/dax
+ccflags-y := -I$(src)/$(NVDIMM_SRC)/
 
 obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o
 obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o
@@ -31,6 +31,7 @@ nfit-y := $(ACPI_SRC)/nfit.o
 nfit-y += config_check.o
 
 nd_pmem-y := $(NVDIMM_SRC)/pmem.o
+nd_pmem-y += pmem-dax.o
 nd_pmem-y += config_check.o
 
 nd_btt-y := $(NVDIMM_SRC)/btt.o

tools/testing/nvdimm/pmem-dax.c

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2014-2016, 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/blkdev.h>
+#include <pmem.h>
+#include <nd.h>
+
+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;
+	resource_size_t offset = sector * 512 + pmem->data_offset;
+
+	/* disable DAX for nfit_test pmem devices */
+	if (get_nfit_res(pmem->phys_addr + offset)) {
+		dev_info_once(pmem->bb.dev, "dax is disabled for nfit_test\n");
+		return -EIO;
+	}
+
+	if (unlikely(is_bad_pmem(&pmem->bb, sector, size)))
+		return -EIO;
+	*kaddr = pmem->virt_addr + offset;
+	*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
+
+	/*
+	 * If badblocks are present, limit known good range to the
+	 * requested range.
+	 */
+	if (unlikely(pmem->bb.count))
+		return size;
+	return pmem->size - pmem->pfn_pad - offset;
+}

tools/testing/nvdimm/test/iomap.c

@@ -52,7 +52,7 @@ static struct nfit_test_resource *__get_nfit_res(resource_size_t resource)
 	return NULL;
 }
 
-static struct nfit_test_resource *get_nfit_res(resource_size_t resource)
+struct nfit_test_resource *get_nfit_res(resource_size_t resource)
 {
 	struct nfit_test_resource *res;
 
@@ -62,6 +62,7 @@ static struct nfit_test_resource *get_nfit_res(resource_size_t resource)
 
 	return res;
 }
+EXPORT_SYMBOL(get_nfit_res);
 
 void __iomem *__nfit_test_ioremap(resource_size_t offset, unsigned long size,
 		void __iomem *(*fallback_fn)(resource_size_t, unsigned long))

tools/testing/nvdimm/test/nfit_test.h

@@ -12,6 +12,7 @@
  */
 #ifndef __NFIT_TEST_H__
 #define __NFIT_TEST_H__
+#include <linux/list.h>
 
 struct nfit_test_resource {
 	struct list_head list;
@@ -26,4 +27,5 @@ void __iomem *__wrap_ioremap_nocache(resource_size_t offset,
 void __wrap_iounmap(volatile void __iomem *addr);
 void nfit_test_setup(nfit_test_lookup_fn lookup);
 void nfit_test_teardown(void);
+struct nfit_test_resource *get_nfit_res(resource_size_t resource);
 #endif