[PATCH] genalloc: add support of multiple gen_pools per device

[Vladimir Zapolskiy]

This change adds two more exported interfaces to genalloc:

* devm_gen_pool_create_named() -- same as devm_gen_pool_create(), but
  the created gen_pool object can be referenced by a given name,
* dev_get_gen_pool_named() -- same as dev_get_gen_pool(), but allows
  to get a previously registered particular gen_pool instance by name

Also the change extends the logic of of_get_named_gen_pool(), if
there is no associated platform device with a given device node, it
attempts to get a label property or device node name (= repeats MTD
OF partition standard) and seeks for a named gen_pool registered by
parent device node device.

The main idea of the change is to allow registration of independent
gen_pools under the same umbrella device, say "partitions" on "storage
device", the original functionality of one "partition" per "storage
device" is untouched.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@xxxxxxxxxx>
---
 include/linux/genalloc.h |  6 ++++
 lib/genalloc.c           | 74 ++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 78 insertions(+), 2 deletions(-)

diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index 1ccaab4..213645f 100644
--- a/include/linux/genalloc.h
+++ b/include/linux/genalloc.h
@@ -59,6 +59,8 @@ struct gen_pool {
 
 	genpool_algo_t algo;		/* allocation function */
 	void *data;
+
+	const char *name;
 };
 
 /*
@@ -117,8 +119,12 @@ extern unsigned long gen_pool_first_fit_order_align(unsigned long *map,
 extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
 		unsigned long start, unsigned int nr, void *data);
 
+extern struct gen_pool *devm_gen_pool_create_named(struct device *dev,
+		int min_alloc_order, int nid, const char *name);
 extern struct gen_pool *devm_gen_pool_create(struct device *dev,
 		int min_alloc_order, int nid);
+extern struct gen_pool *dev_get_gen_pool_named(struct device *dev,
+		const char *name);
 extern struct gen_pool *dev_get_gen_pool(struct device *dev);
 
 bool addr_in_gen_pool(struct gen_pool *pool, unsigned long start,
diff --git a/lib/genalloc.c b/lib/genalloc.c
index d214866..3300071 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -602,6 +602,30 @@ struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
 EXPORT_SYMBOL(devm_gen_pool_create);
 
 /**
+ * devm_gen_pool_create_named - managed gen_pool_create
+ * @dev: device that provides the gen_pool
+ * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
+ * @nid: node id of the node the pool structure should be allocated on, or -1
+ * @name: name of a gen_pool within all gen_pool associated with the device
+ *
+ * Create a new special memory pool that can be used to manage special purpose
+ * memory not managed by the regular kmalloc/kfree interface. The pool will be
+ * automatically destroyed by the device management code.
+ */
+struct gen_pool *devm_gen_pool_create_named(struct device *dev,
+		int min_alloc_order, int nid, const char *name)
+{
+	struct gen_pool *pool;
+
+	pool = devm_gen_pool_create(dev, min_alloc_order, nid);
+	if (pool)
+		pool->name = name;
+
+	return pool;
+}
+EXPORT_SYMBOL(devm_gen_pool_create_named);
+
+/**
  * dev_get_gen_pool - Obtain the gen_pool (if any) for a device
  * @dev: device to retrieve the gen_pool from
  *
@@ -618,6 +642,38 @@ struct gen_pool *dev_get_gen_pool(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_get_gen_pool);
 
+static int dev_gen_pool_match(struct device *dev, void *res, void *data)
+{
+	struct gen_pool **p = res;
+
+	/* Always get a match, if no data supplied */
+	if (!data)
+		return 1;
+
+	if (!(*p)->name)
+		return 0;
+
+	return !strcmp((*p)->name, data);
+}
+
+/**
+ * dev_get_gen_pool_named - Obtain the gen_pool (if any) for a device
+ * @dev: device to retrieve the gen_pool from
+ * @name: name of a gen_pool, addresses a particular gen_pool from device
+ *
+ * Returns the gen_pool for the device if one is present, or NULL.
+ */
+struct gen_pool *dev_get_gen_pool_named(struct device *dev, const char *name)
+{
+	struct gen_pool **p = devres_find(dev, devm_gen_pool_release,
+					  dev_gen_pool_match, (void *)name);
+
+	if (!p)
+		return NULL;
+	return *p;
+}
+EXPORT_SYMBOL_GPL(dev_get_gen_pool_named);
+
 #ifdef CONFIG_OF
 /**
  * of_get_named_gen_pool - find a pool by phandle property
@@ -633,16 +689,30 @@ struct gen_pool *of_get_named_gen_pool(struct device_node *np,
 	const char *propname, int index)
 {
 	struct platform_device *pdev;
-	struct device_node *np_pool;
+	struct device_node *np_pool, *parent;
+	const char *name = NULL;
 
 	np_pool = of_parse_phandle(np, propname, index);
 	if (!np_pool)
 		return NULL;
+
 	pdev = of_find_device_by_node(np_pool);
+	if (!pdev) {
+		/* Check if named gen_pool is created by parent node device */
+		parent = of_get_parent(np_pool);
+		pdev = of_find_device_by_node(parent);
+		of_node_put(parent);
+
+		of_property_read_string(np_pool, "label", &name);
+		if (!name)
+			name = np_pool->name;
+	}
 	of_node_put(np_pool);
+
 	if (!pdev)
 		return NULL;
-	return dev_get_gen_pool(&pdev->dev);
+
+	return dev_get_gen_pool_named(&pdev->dev, name);
 }
 EXPORT_SYMBOL_GPL(of_get_named_gen_pool);
 #endif /* CONFIG_OF */
-- 
2.1.4

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