[PATCH v2 01/10] kdbus: fix operator precedence issues in item macros

[Sergei Zviagintsev]

`_i' argument in KDBUS_ITEM_NEXT and KDBUS_ITEMS_END macros is not
enclosed into parentheses when the cast operator is applied, which
leads to improper type conversion if `_i' is supplied as a complex
expression, e.g.

    KDBUS_ITEM_NEXT(condition ? a : b)

KDBUS_ITEMS_SIZE macro has similar issue, missing parentheses around
`_h' when using indirection operator.

Use parentheses properly to guarantee right precedence.

Signed-off-by: Sergei Zviagintsev <sergei@xxxxxxxx>
---
 ipc/kdbus/item.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ipc/kdbus/item.h b/ipc/kdbus/item.h
index eeefd8beac3b..32909e2e7954 100644
--- a/ipc/kdbus/item.h
+++ b/ipc/kdbus/item.h
@@ -21,8 +21,8 @@
 #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_ITEMS_SIZE(_h, _is) ((_h)->size - offsetof(typeof(*_h), _is))
+#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))
 #define KDBUS_ITEM_PAYLOAD_SIZE(_i) ((_i)->size - KDBUS_ITEM_HEADER_SIZE)
@@ -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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