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/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index 4999518739974668a28bf25412007b269f735a28..e1a27074caae2cf9598147b12a41c407e1a45bdb 100644 (file)
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -237,6 +237,8 @@ MEM
   devm_kzalloc()
   devm_kfree()
   devm_kmemdup()
+  devm_get_free_pages()
+  devm_free_pages()
 
 IIO
   devm_iio_device_alloc()

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index d0914cba2413834cb7b712cbcc7e99fbe3a0f31b..52302946770f59b827a3a74e2dd73c220553dc93 100644 (file)
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -852,3 +852,79 @@ void *devm_kmemdup(struct device *dev, const void *src, size_t len, gfp_t gfp)
        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);

diff --git a/include/linux/device.h b/include/linux/device.h
index ab871588da8997e936ae49e8a96e42915f03f60b..3dc69a2faa51ce40bb3937779131cfa022e15965 100644 (file)
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -626,6 +626,10 @@ extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp);
 extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
                          gfp_t gfp);
 
+extern unsigned long devm_get_free_pages(struct device *dev,
+                                        gfp_t gfp_mask, unsigned int order);
+extern void devm_free_pages(struct device *dev, unsigned long addr);
+
 void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
 void __iomem *devm_request_and_ioremap(struct device *dev,
                        struct resource *res);