Merge tag 'driver-core-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is a small number of driver core patches for 4.20-rc1.

  Not much happened here this merge window, only a very tiny number of
  patches that do:

   - add BUS_ATTR_WO() for use by drivers

   - component error path fixes

   - kernfs range check fix

   - other tiny error path fixes and const changes

  All of these have been in linux-next with no reported issues for a
  while"

* tag 'driver-core-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  devres: provide devm_kstrdup_const()
  mm: move is_kernel_rodata() to asm-generic/sections.h
  devres: constify p in devm_kfree()
  driver core: add BUS_ATTR_WO() macro
  kernfs: Fix range checks in kernfs_get_target_path
  component: fix loop condition to call unbind() if bind() fails
  drivers/base/devtmpfs.c: don't pretend path is const in delete_path
  kernfs: update comment about kernfs_path() return value

3 files changed, 38 insertions, 6 deletions

diff --git a/drivers/base/component.c b/drivers/base/component.c
index 8946dfee4768..e8d676fad0c9 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -536,9 +536,9 @@ int component_bind_all(struct device *master_dev, void *data)
 		}
 
 	if (ret != 0) {
-		for (; i--; )
-			if (!master->match->compare[i].duplicate) {
-				c = master->match->compare[i].component;
+		for (; i > 0; i--)
+			if (!master->match->compare[i - 1].duplicate) {
+				c = master->match->compare[i - 1].component;
 				component_unbind(c, master, data);
 			}
 	}
diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index f98a097e73f2..4aaf00d2098b 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -11,6 +11,8 @@
 #include <linux/slab.h>
 #include <linux/percpu.h>
 
+#include <asm/sections.h>
+
 #include "base.h"
 
 struct devres_node {
@@ -823,6 +825,28 @@ char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
 EXPORT_SYMBOL_GPL(devm_kstrdup);
 
 /**
+ * devm_kstrdup_const - resource managed conditional string duplication
+ * @dev: device for which to duplicate the string
+ * @s: the string to duplicate
+ * @gfp: the GFP mask used in the kmalloc() call when allocating memory
+ *
+ * Strings allocated by devm_kstrdup_const will be automatically freed when
+ * the associated device is detached.
+ *
+ * RETURNS:
+ * Source string if it is in .rodata section otherwise it falls back to
+ * devm_kstrdup.
+ */
+const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
+{
+	if (is_kernel_rodata((unsigned long)s))
+		return s;
+
+	return devm_kstrdup(dev, s, gfp);
+}
+EXPORT_SYMBOL_GPL(devm_kstrdup_const);
+
+/**
  * devm_kvasprintf - Allocate resource managed space and format a string
  *		     into that.
  * @dev: Device to allocate memory for
@@ -885,11 +909,19 @@ EXPORT_SYMBOL_GPL(devm_kasprintf);
  *
  * Free memory allocated with devm_kmalloc().
  */
-void devm_kfree(struct device *dev, void *p)
+void devm_kfree(struct device *dev, const void *p)
 {
 	int rc;
 
-	rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p);
+	/*
+	 * Special case: pointer to a string in .rodata returned by
+	 * devm_kstrdup_const().
+	 */
+	if (unlikely(is_kernel_rodata((unsigned long)p)))
+		return;
+
+	rc = devres_destroy(dev, devm_kmalloc_release,
+			    devm_kmalloc_match, (void *)p);
 	WARN_ON(rc);
 }
 EXPORT_SYMBOL_GPL(devm_kfree);
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index f7768077e817..b93fc862d365 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -252,7 +252,7 @@ static int dev_rmdir(const char *name)
 
 static int delete_path(const char *nodepath)
 {
-	const char *path;
+	char *path;
 	int err = 0;
 
 	path = kstrdup(nodepath, GFP_KERNEL);