diff mbox

[dpdk-dev,RFC,1/6] eal: define container macro

Message ID 1479360605-20558-2-git-send-email-shreyansh.jain@nxp.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers

Checks

Context Check Description
checkpatch/checkpatch success coding style OK

Commit Message

Shreyansh Jain Nov. 17, 2016, 5:30 a.m. UTC 
  From: Jan Viktorin <viktorin@rehivetech.com>

Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
---
 lib/librte_eal/common/include/rte_common.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

Comments

Jan Blunck Nov. 17, 2016, 12:06 p.m. UTC | #1 
On Thu, Nov 17, 2016 at 6:30 AM, Shreyansh Jain <shreyansh.jain@nxp.com> wrote:
> From: Jan Viktorin <viktorin@rehivetech.com>
>
> Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
> Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> ---
>  lib/librte_eal/common/include/rte_common.h | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
> index db5ac91..8152bd9 100644
> --- a/lib/librte_eal/common/include/rte_common.h
> +++ b/lib/librte_eal/common/include/rte_common.h
> @@ -331,6 +331,24 @@ 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(p, type, member) \
> +       ((type *) (((char *) (p)) - offsetof(type, member)))

Are there any reasons why you choose to implement this in a non-type
safe way? Catching obvious bugs at compile time is in the interest of
us and our users from my point of view.


> +#endif
> +
>  #define _RTE_STR(x) #x
>  /** Take a macro value and get a string version of it */
>  #define RTE_STR(x) _RTE_STR(x)
> --
> 2.7.4
>
Shreyansh Jain Nov. 17, 2016, 1:01 p.m. UTC | #2 
On Thursday 17 November 2016 05:36 PM, Jan Blunck wrote:
> On Thu, Nov 17, 2016 at 6:30 AM, Shreyansh Jain <shreyansh.jain@nxp.com> wrote:
>> From: Jan Viktorin <viktorin@rehivetech.com>
>>
>> Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
>> Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
>> ---
>>  lib/librte_eal/common/include/rte_common.h | 18 ++++++++++++++++++
>>  1 file changed, 18 insertions(+)
>>
>> diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
>> index db5ac91..8152bd9 100644
>> --- a/lib/librte_eal/common/include/rte_common.h
>> +++ b/lib/librte_eal/common/include/rte_common.h
>> @@ -331,6 +331,24 @@ 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(p, type, member) \
>> +       ((type *) (((char *) (p)) - offsetof(type, member)))
>
> Are there any reasons why you choose to implement this in a non-type
> safe way? Catching obvious bugs at compile time is in the interest of
> us and our users from my point of view.

No specific reason. I just took an existing patchset floating in ML. If 
you can point me to some better implementation, I will use that.

>
>
>> +#endif
>> +
>>  #define _RTE_STR(x) #x
>>  /** Take a macro value and get a string version of it */
>>  #define RTE_STR(x) _RTE_STR(x)
>> --
>> 2.7.4
>>
>
diff mbox

Patch

diff --git a/lib/librte_eal/common/include/rte_common.h b/lib/librte_eal/common/include/rte_common.h
index db5ac91..8152bd9 100644
--- a/lib/librte_eal/common/include/rte_common.h
+++ b/lib/librte_eal/common/include/rte_common.h
@@ -331,6 +331,24 @@  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(p, type, member) \
+	((type *) (((char *) (p)) - offsetof(type, member)))
+#endif
+
 #define _RTE_STR(x) #x
 /** Take a macro value and get a string version of it */
 #define RTE_STR(x) _RTE_STR(x)