[PATCH] kdbus: fix type conversion in item macroses

[Sergei Zviagintsev]

KDBUS_ITEM_NEXT and KDBUS_ITEMS_END macroses do not enclose _i argument
into parentheses when applying the cast operator. If complex expression
passed, e.g.

    KDBUS_ITEM_NEXT(condition ? a : b)

then type conversion to (u8 *) will go wrong due to precedence rules.

Use parentheses properly. Update documentation.

Signed-off-by: Sergei Zviagintsev <sergei@xxxxxxxx>
---
 Documentation/kdbus/kdbus.item.xml | 2 +-
 ipc/kdbus/item.h                   | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Documentation/kdbus/kdbus.item.xml b/Documentation/kdbus/kdbus.item.xml
index 09f8b903116f..b0eeeef995af 100644
--- a/Documentation/kdbus/kdbus.item.xml
+++ b/Documentation/kdbus/kdbus.item.xml
@@ -69,7 +69,7 @@
 #define KDBUS_ALIGN8(val) (((val) + 7) & ~7)
 
 #define KDBUS_ITEM_NEXT(item) \
-    (typeof(item))(((uint8_t *)item) + KDBUS_ALIGN8((item)->size))
+    (typeof(item))((uint8_t *)(item) + KDBUS_ALIGN8((item)->size))
 
 #define KDBUS_ITEM_FOREACH(item, head, first)                      \
     for (item = (head)->first;                                     \
diff --git a/ipc/kdbus/item.h b/ipc/kdbus/item.h
index eeefd8beac3b..03612368b3bb 100644
--- a/ipc/kdbus/item.h
+++ b/ipc/kdbus/item.h
@@ -21,7 +21,7 @@
 #include "util.h"
 
 /* generic access and iterators over a stream of items */
-#define KDBUS_ITEM_NEXT(_i) (typeof(_i))(((u8 *)_i) + KDBUS_ALIGN8((_i)->size))
+#define KDBUS_ITEM_NEXT(_i) (typeof(_i))((u8 *)(_i) + KDBUS_ALIGN8((_i)->size))
 #define KDBUS_ITEMS_SIZE(_h, _is) ((_h)->size - offsetof(typeof(*_h), _is))
 #define KDBUS_ITEM_HEADER_SIZE offsetof(struct kdbus_item, data)
 #define KDBUS_ITEM_SIZE(_s) KDBUS_ALIGN8(KDBUS_ITEM_HEADER_SIZE + (_s))
@@ -40,7 +40,7 @@
 	 (u8 *)(_i) >= (u8 *)(_is))
 
 #define KDBUS_ITEMS_END(_i, _is, _s)					\
-	((u8 *)_i == ((u8 *)(_is) + KDBUS_ALIGN8(_s)))
+	((u8 *)(_i) == ((u8 *)(_is) + KDBUS_ALIGN8(_s)))
 
 /**
  * struct kdbus_item_header - Describes the fix part of an item
-- 
1.8.3.1

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