1 files changed, 62 insertions, 39 deletions

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index 2152eec0c135..f54db6d138ab 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -576,7 +576,10 @@ void *devres_open_group(struct device *dev, void *id, gfp_t gfp)
 }
 EXPORT_SYMBOL_GPL(devres_open_group);
 
-/* Find devres group with ID @id.  If @id is NULL, look for the latest. */
+/*
+ * Find devres group with ID @id.  If @id is NULL, look for the latest open
+ * group.
+ */
 static struct devres_group *find_group(struct device *dev, void *id)
 {
 	struct devres_node *node;
@@ -687,6 +690,13 @@ int devres_release_group(struct device *dev, void *id)
 		spin_unlock_irqrestore(&dev->devres_lock, flags);
 
 		release_nodes(dev, &todo);
+	} else if (list_empty(&dev->devres_head)) {
+		/*
+		 * dev is probably dying via devres_release_all(): groups
+		 * have already been removed and are on the process of
+		 * being released - don't touch and don't warn.
+		 */
+		spin_unlock_irqrestore(&dev->devres_lock, flags);
 	} else {
 		WARN_ON(1);
 		spin_unlock_irqrestore(&dev->devres_lock, flags);
@@ -749,26 +759,50 @@ int __devm_add_action(struct device *dev, void (*action)(void *), void *data, co
 }
 EXPORT_SYMBOL_GPL(__devm_add_action);
 
+bool devm_is_action_added(struct device *dev, void (*action)(void *), void *data)
+{
+	struct action_devres devres = {
+		.data = data,
+		.action = action,
+	};
+
+	return devres_find(dev, devm_action_release, devm_action_match, &devres);
+}
+EXPORT_SYMBOL_GPL(devm_is_action_added);
+
 /**
- * devm_remove_action() - removes previously added custom action
+ * devm_remove_action_nowarn() - removes previously added custom action
  * @dev: Device that owns the action
  * @action: Function implementing the action
  * @data: Pointer to data passed to @action implementation
  *
  * Removes instance of @action previously added by devm_add_action().
  * Both action and data should match one of the existing entries.
+ *
+ * In contrast to devm_remove_action(), this function does not WARN() if no
+ * entry could have been found.
+ *
+ * This should only be used if the action is contained in an object with
+ * independent lifetime management, e.g. the Devres rust abstraction.
+ *
+ * Causing the warning from regular driver code most likely indicates an abuse
+ * of the devres API.
+ *
+ * Returns: 0 on success, -ENOENT if no entry could have been found.
  */
-void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
+int devm_remove_action_nowarn(struct device *dev,
+			      void (*action)(void *),
+			      void *data)
 {
 	struct action_devres devres = {
 		.data = data,
 		.action = action,
 	};
 
-	WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
-			       &devres));
+	return devres_destroy(dev, devm_action_release, devm_action_match,
+			      &devres);
 }
-EXPORT_SYMBOL_GPL(devm_remove_action);
+EXPORT_SYMBOL_GPL(devm_remove_action_nowarn);
 
 /**
  * devm_release_action() - release previously added custom action
@@ -953,17 +987,10 @@ EXPORT_SYMBOL_GPL(devm_krealloc);
  */
 char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
 {
-	size_t size;
-	char *buf;
-
 	if (!s)
 		return NULL;
 
-	size = strlen(s) + 1;
-	buf = devm_kmalloc(dev, size, gfp);
-	if (buf)
-		memcpy(buf, s, size);
-	return buf;
+	return devm_kmemdup(dev, s, strlen(s) + 1, gfp);
 }
 EXPORT_SYMBOL_GPL(devm_kstrdup);
 
@@ -1090,6 +1117,27 @@ void *devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp)
 }
 EXPORT_SYMBOL_GPL(devm_kmemdup);
 
+/**
+ * devm_kmemdup_const - conditionally duplicate and manage a region of memory
+ *
+ * @dev: Device this memory belongs to
+ * @src: memory region to duplicate
+ * @len: memory region length,
+ * @gfp: GFP mask to use
+ *
+ * Return: source address if it is in .rodata or the return value of kmemdup()
+ * to which the function falls back otherwise.
+ */
+const void *
+devm_kmemdup_const(struct device *dev, const void *src, size_t len, gfp_t gfp)
+{
+	if (is_kernel_rodata((unsigned long)src))
+		return src;
+
+	return devm_kmemdup(dev, src, len, gfp);
+}
+EXPORT_SYMBOL_GPL(devm_kmemdup_const);
+
 struct pages_devres {
 	unsigned long addr;
 	unsigned int order;
@@ -1174,13 +1222,6 @@ static void devm_percpu_release(struct device *dev, void *pdata)
 	free_percpu(p);
 }
 
-static int devm_percpu_match(struct device *dev, void *data, void *p)
-{
-	struct devres *devr = container_of(data, struct devres, data);
-
-	return *(void **)devr->data == p;
-}
-
 /**
  * __devm_alloc_percpu - Resource-managed alloc_percpu
  * @dev: Device to allocate per-cpu memory for
@@ -1216,21 +1257,3 @@ void __percpu *__devm_alloc_percpu(struct device *dev, size_t size,
 	return pcpu;
 }
 EXPORT_SYMBOL_GPL(__devm_alloc_percpu);
-
-/**
- * devm_free_percpu - Resource-managed free_percpu
- * @dev: Device this memory belongs to
- * @pdata: Per-cpu memory to free
- *
- * Free memory allocated with devm_alloc_percpu().
- */
-void devm_free_percpu(struct device *dev, void __percpu *pdata)
-{
-	/*
-	 * Use devres_release() to prevent memory leakage as
-	 * devm_free_pages() does.
-	 */
-	WARN_ON(devres_release(dev, devm_percpu_release, devm_percpu_match,
-			       (void *)(__force unsigned long)pdata));
-}
-EXPORT_SYMBOL_GPL(devm_free_percpu);