nvdimm: Use kstrtobool() instead of strtobool()

strtobool() is the same as kstrtobool().
However, the latter is more used within the kernel.

In order to remove strtobool() and slightly simplify kstrtox.h, switch to
the other function name.

While at it, include the corresponding header file (<linux/kstrtox.h>)

Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

drivers/nvdimm/namespace_devs.c

@@ -2,6 +2,7 @@
 /*
  * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
  */
+#include <linux/kstrtox.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/sort.h>
@@ -1338,7 +1339,7 @@ static ssize_t force_raw_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	bool force_raw;
-	int rc = strtobool(buf, &force_raw);
+	int rc = kstrtobool(buf, &force_raw);
 
 	if (rc)
 		return rc;

drivers/nvdimm/pmem.c

@@ -17,6 +17,7 @@
 #include <linux/moduleparam.h>
 #include <linux/badblocks.h>
 #include <linux/memremap.h>
+#include <linux/kstrtox.h>
 #include <linux/vmalloc.h>
 #include <linux/blk-mq.h>
 #include <linux/pfn_t.h>
@@ -385,7 +386,7 @@ static ssize_t write_cache_store(struct device *dev,
 	bool write_cache;
 	int rc;
 
-	rc = strtobool(buf, &write_cache);
+	rc = kstrtobool(buf, &write_cache);
 	if (rc)
 		return rc;
 	dax_write_cache(pmem->dax_dev, write_cache);

drivers/nvdimm/region_devs.c

@@ -5,6 +5,7 @@
 #include <linux/scatterlist.h>
 #include <linux/memregion.h>
 #include <linux/highmem.h>
+#include <linux/kstrtox.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/hash.h>
@@ -275,7 +276,7 @@ static ssize_t deep_flush_store(struct device *dev, struct device_attribute *att
 		const char *buf, size_t len)
 {
 	bool flush;
-	int rc = strtobool(buf, &flush);
+	int rc = kstrtobool(buf, &flush);
 	struct nd_region *nd_region = to_nd_region(dev);
 
 	if (rc)
@@ -530,7 +531,7 @@ static ssize_t read_only_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	bool ro;
-	int rc = strtobool(buf, &ro);
+	int rc = kstrtobool(buf, &ro);
 	struct nd_region *nd_region = to_nd_region(dev);
 
 	if (rc)