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J . Bottomley" , Greg Kroah-Hartman , Jens Axboe Subject: [PATCH] linux/kernel.h: add container_from() Date: Thu, 27 Aug 2020 07:06:36 +0530 Message-Id: <20200827013636.149307-1-allen.lkml@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Introduce container_from() as a generic helper instead of sub-systems defining a private from_* API (Eg: from_tasklets recently introduced in 12cc923f1ccc: Tasklet: Introduce new initialization API) The helper is similar to container_of() in argument order with the difference of naming the containing structure instead of having to specify its type. Suggested-by: James E.J. Bottomley Suggested-by: Greg Kroah-Hartman Suggested-by: Jens Axboe Signed-off-by: Allen Pais --- include/linux/kernel.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 500def620d8f..9d446324a8be 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -1019,6 +1019,15 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } "pointer type mismatch in container_of()"); \ IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \ ((type *)(__mptr - offsetof(type, member))); }) +/** + * container_from - cast a member of a structure out to the containing structure + * @ptr: the pointer to the member. + * @container: the type of the container struct. + * @member: the name of the member within the struct. + * + */ +#define container_from(ptr, container, member) \ + container_of(ptr, typeof(*container), member) /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ #ifdef CONFIG_FTRACE_MCOUNT_RECORD -- 2.25.1