configfs: Introduce config_item_get_unless_zero()

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
[hch: minor style tweak]
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/configfs/item.c b/fs/configfs/item.c
index 8b2a994042ddeb2d1b8c00bbee3436e79fff52ad..a66f6624d89943997d1d35ead214aee85857e5d7 100644 (file)
--- a/fs/configfs/item.c
+++ b/fs/configfs/item.c
@@ -138,6 +138,14 @@ struct config_item *config_item_get(struct config_item *item)
 }
 EXPORT_SYMBOL(config_item_get);
 
+struct config_item *config_item_get_unless_zero(struct config_item *item)
+{
+       if (item && kref_get_unless_zero(&item->ci_kref))
+               return item;
+       return NULL;
+}
+EXPORT_SYMBOL(config_item_get_unless_zero);
+
 static void config_item_cleanup(struct config_item *item)
 {
        struct config_item_type *t = item->ci_type;

diff --git a/include/linux/configfs.h b/include/linux/configfs.h
index 2319b8c108e87b9e87c11cc4c9aa314d24eb0364..c9670904968329ce3032825d55b28a72cb8b223c 100644 (file)
--- a/include/linux/configfs.h
+++ b/include/linux/configfs.h
@@ -74,7 +74,8 @@ extern void config_item_init_type_name(struct config_item *item,
                                       const char *name,
                                       struct config_item_type *type);
 
-extern struct config_item * config_item_get(struct config_item *);
+extern struct config_item *config_item_get(struct config_item *);
+extern struct config_item *config_item_get_unless_zero(struct config_item *);
 extern void config_item_put(struct config_item *);
 
 struct config_item_type {