Hi Ferruh,

Forgot to add a comment in previous reply to this email:

On Monday 29 August 2016 10:13 PM, Ferruh Yigit wrote:

On 8/26/2016 2:56 PM, Shreyansh Jain wrote:

quoted

Signed-off-by: Jan Viktorin <redacted>
Signed-off-by: Shreyansh Jain <redacted>
---
 lib/librte_eal/common/include/rte_common.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index 332f2a4..a9b6792 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h

@@ -322,6 +322,22 @@ 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);
+ */
+#define container_of(p, type, member) \
+	((type *) (((char *) (p)) - offsetof(type, member)))
+
 #define _RTE_STR(x) #x
 /** Take a macro value and get a string version of it */
 #define RTE_STR(x) _RTE_STR(x)

This gives compilation error for mlx5, because the libraries mlx depends
defines same macro:
..../rte_common.h:338:9: error: 'container_of' macro redefined
/usr/include/infiniband/verbs.h:77:9: note: previous definition is here

Does it make sense to protect macro with
#ifndef container_of
....
#endif

Sounds good - probably would prevent double definition in future if 
someone includes any linux header having similar definition.

Generally the container_of definitions are consistent - that is, they 
would invariably use the offsetof from member. In which case, creating a 
new dpdk_* would only duplicate. Thus, I prefer the #ifndef.

OR

add a dpdk prefix?


Regards,
ferruh

-
Shreyansh