From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shreyansh Jain Subject: [PATCH v3 01/12] eal: define container_of macro Date: Fri, 16 Dec 2016 18:40:42 +0530 Message-ID: <1481893853-31790-2-git-send-email-shreyansh.jain@nxp.com> References: <1481636232-2300-1-git-send-email-shreyansh.jain@nxp.com> <1481893853-31790-1-git-send-email-shreyansh.jain@nxp.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , Jan Blunck , Jan Viktorin , Shreyansh Jain To: , Return-path: Received: from NAM03-DM3-obe.outbound.protection.outlook.com (mail-dm3nam03on0046.outbound.protection.outlook.com [104.47.41.46]) by dpdk.org (Postfix) with ESMTP id 1EB5E5584 for ; Fri, 16 Dec 2016 14:08:55 +0100 (CET) In-Reply-To: <1481893853-31790-1-git-send-email-shreyansh.jain@nxp.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" From: Jan Blunck 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 Signed-off-by: Shreyansh Jain [jblunck@infradead.org: add type checking and __extension__] Signed-off-by: Jan Blunck --- 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 + #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