On Thursday 08 December 2016 12:31 PM, Shreyansh Jain wrote:
Hello Jan,
Need your help in resolving the checkpatch issue for this patch.
I have used this in EAL Bus series [1].
[1] http://dpdk.org/ml/archives/dev/2016-December/051350.html
On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:
This macro is based on Jan Viktorin's original patch but also checks the
type of the passed pointer against the type of the member.
Signed-off-by: Jan Viktorin <vikto...@rehivetech.com>
Signed-off-by: Shreyansh Jain <shreyansh.j...@nxp.com>
[jblu...@infradead.org: add type checking and __extension__]
Signed-off-by: Jan Blunck <jblu...@infradead.org>
---
lib/librte_eal/common/include/rte_common.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/lib/librte_eal/common/include/rte_common.h
b/lib/librte_eal/common/include/rte_common.h
index db5ac91..8dda3e2 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -331,6 +331,26 @@ rte_bsf32(uint32_t v)
#define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER)
#endif
+/**
+ * Return pointer to the wrapping struct instance.
+ *
+ * Example:
+ *
+ * struct wrapper {
+ * ...
+ * struct child c;
+ * ...
+ * };
+ *
+ * struct child *x = obtain(...);
+ * struct wrapper *w = container_of(x, struct wrapper, c);
+ */
+#ifndef container_of
+#define container_of(ptr, type, member) __extension__ ({ \
+ typeof(((type *)0)->member) *_ptr = (ptr); \
+ (type *)(((char *)_ptr) - offsetof(type, member)); })
+#endif
(I think there was discussion in ML about this but where, I couldn't
find it).
Above code snippet doesn't go down well with the checkpatch script. It
reports:
---->8----
ERROR:COMPLEX_MACRO: Macros with complex values should be enclosed in
parentheses
#40: FILE: lib/librte_eal/common/include/rte_common.h:349:
+#define container_of(ptr, type, member) __extension__ ({ \
+ typeof(((type *)0)->member) *_ptr = (ptr); \
+ (type *)(((char *)_ptr) - offsetof(type,
member)); })
ERROR:SPACING: need consistent spacing around '*' (ctx:WxV)
#41: FILE: lib/librte_eal/common/include/rte_common.h:350:
+ typeof(((type *)0)->member) *_ptr = (ptr); \
---->8----
Second error is primarily because of '*<space>_ptr' rather than '*_ptr'.
Is do{ ... }while(0) the fix for the first one?
This:
---->8----
#ifndef container_of
#define container_of(ptr, type, member) do { \
__extension__ \
typeof(((type *)0)->member) * _ptr = (ptr); \
(type *)(((char *)_ptr) - offsetof(type, member));\
} while (0)
#endif
---->8----
Seems to be ok with checkpatch. Do you see any technical/compiler issue
with this?
My bad.
obviously a 'do{ .. } while(0)' will not work in case of assignment.
Any other hints as to how to remove this checkpatch issue?
+
#define _RTE_STR(x) #x
/** Take a macro value and get a string version of it */
#define RTE_STR(x) _RTE_STR(x)
-
Shreyansh
