devres: Add devm_get_free_pages API
devm_get_free_pages() and devm_free_pages() are the managed counterparts
for __get_free_pages() and free_pages().
Signed-off-by: Eli Billauer <eli.billauer@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index d0914cb..5230294 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -852,3 +852,79 @@
return p;
}
EXPORT_SYMBOL_GPL(devm_kmemdup);
+
+struct pages_devres {
+ unsigned long addr;
+ unsigned int order;
+};
+
+static int devm_pages_match(struct device *dev, void *res, void *p)
+{
+ struct pages_devres *devres = res;
+ struct pages_devres *target = p;
+
+ return devres->addr == target->addr;
+}
+
+static void devm_pages_release(struct device *dev, void *res)
+{
+ struct pages_devres *devres = res;
+
+ free_pages(devres->addr, devres->order);
+}
+
+/**
+ * devm_get_free_pages - Resource-managed __get_free_pages
+ * @dev: Device to allocate memory for
+ * @gfp_mask: Allocation gfp flags
+ * @order: Allocation size is (1 << order) pages
+ *
+ * Managed get_free_pages. Memory allocated with this function is
+ * automatically freed on driver detach.
+ *
+ * RETURNS:
+ * Address of allocated memory on success, 0 on failure.
+ */
+
+unsigned long devm_get_free_pages(struct device *dev,
+ gfp_t gfp_mask, unsigned int order)
+{
+ struct pages_devres *devres;
+ unsigned long addr;
+
+ addr = __get_free_pages(gfp_mask, order);
+
+ if (unlikely(!addr))
+ return 0;
+
+ devres = devres_alloc(devm_pages_release,
+ sizeof(struct pages_devres), GFP_KERNEL);
+ if (unlikely(!devres)) {
+ free_pages(addr, order);
+ return 0;
+ }
+
+ devres->addr = addr;
+ devres->order = order;
+
+ devres_add(dev, devres);
+ return addr;
+}
+EXPORT_SYMBOL_GPL(devm_get_free_pages);
+
+/**
+ * devm_free_pages - Resource-managed free_pages
+ * @dev: Device this memory belongs to
+ * @addr: Memory to free
+ *
+ * Free memory allocated with devm_get_free_pages(). Unlike free_pages,
+ * there is no need to supply the @order.
+ */
+void devm_free_pages(struct device *dev, unsigned long addr)
+{
+ struct pages_devres devres = { .addr = addr };
+
+ WARN_ON(devres_release(dev, devm_pages_release, devm_pages_match,
+ &devres));
+}
+EXPORT_SYMBOL_GPL(devm_free_pages);
