[PATCH 2/2] genalloc: add support of multiple gen_pools per device

[Vladimir Zapolskiy]

This change fills devm_gen_pool_create()/gen_pool_get() "name"
argument stub with contents and extends of_gen_pool_get()
functionality on this basis.

If there is no associated platform device with a device node passed to
of_gen_pool_get(), the function attempts to get a label property or
device node name (= repeats MTD OF partition standard) and seeks for a
named gen_pool registered by device of the parent device node.

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 |  2 ++
 lib/genalloc.c           | 54 +++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h
index 6afa65e..7ff168d 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;
 };
 
 /*
diff --git a/lib/genalloc.c b/lib/genalloc.c
index 7cf19a5..259582b 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -160,6 +160,7 @@ struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
 		pool->min_alloc_order = min_alloc_order;
 		pool->algo = gen_pool_first_fit;
 		pool->data = NULL;
+		pool->name = NULL;
 	}
 	return pool;
 }
@@ -252,8 +253,8 @@ void gen_pool_destroy(struct gen_pool *pool)
 
 		kfree(chunk);
 	}
+	kfree(pool->name);
 	kfree(pool);
-	return;
 }
 EXPORT_SYMBOL(gen_pool_destroy);
 
@@ -570,6 +571,20 @@ static void devm_gen_pool_release(struct device *dev, void *res)
 	gen_pool_destroy(*(struct gen_pool **)res);
 }
 
+static int devm_gen_pool_match(struct device *dev, void *res, void *data)
+{
+	struct gen_pool **p = res;
+
+	/* NULL data matches only a pool without an assigned name */
+	if (!data && !(*p)->name)
+		return 1;
+
+	if (!data || !(*p)->name)
+		return 0;
+
+	return !strcmp((*p)->name, data);
+}
+
 /**
  * gen_pool_get - Obtain the gen_pool (if any) for a device
  * @dev: device to retrieve the gen_pool from
@@ -580,7 +595,7 @@ static void devm_gen_pool_release(struct device *dev, void *res)
 struct gen_pool *gen_pool_get(struct device *dev, const char *name)
 {
 	struct gen_pool **p = devres_find(dev, devm_gen_pool_release,
-					  NULL, NULL);
+					  devm_gen_pool_match, (void *)name);
 
 	if (!p)
 		return NULL;
@@ -603,21 +618,32 @@ struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
 				      int nid, const char *name)
 {
 	struct gen_pool **ptr, *pool;
+	const char *pool_name = NULL;
 
 	/* Check that genpool to be created is uniquely addressed on device */
 	if (gen_pool_get(dev, name))
 		return ERR_PTR(-EINVAL);
 
+	if (name) {
+		pool_name = kstrdup_const(name, GFP_KERNEL);
+		if (!pool_name)
+			return ERR_PTR(-ENOMEM);
+	}
+
 	ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
+	if (!ptr) {
+		kfree(pool_name);
 		return ERR_PTR(-ENOMEM);
+	}
 
 	pool = gen_pool_create(min_alloc_order, nid);
 	if (pool) {
 		*ptr = pool;
+		pool->name = pool_name;
 		devres_add(dev, ptr);
 	} else {
 		devres_free(ptr);
+		kfree(pool_name);
 		return ERR_PTR(-ENOMEM);
 	}
 
@@ -640,16 +666,30 @@ struct gen_pool *of_gen_pool_get(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;
+	struct gen_pool *pool = 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;
+	}
+	if (pdev)
+		pool = gen_pool_get(&pdev->dev, name);
 	of_node_put(np_pool);
-	if (!pdev)
-		return NULL;
-	return gen_pool_get(&pdev->dev, NULL);
+
+	return pool;
 }
 EXPORT_SYMBOL_GPL(of_gen_pool_get);
 #endif /* CONFIG_OF */
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/