From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: [PATCH 05/38] stddef.h: Introduce sizeof_field() Date: Wed, 10 Jan 2018 18:02:37 -0800 Message-ID: <1515636190-24061-6-git-send-email-keescook@chromium.org> References: <1515636190-24061-1-git-send-email-keescook@chromium.org> Cc: Kees Cook , Linus Torvalds , David Windsor , Alexander Viro , Andrew Morton , Andy Lutomirski , Christoph Hellwig , Christoph Lameter , "David S. Miller" , Laura Abbott , Mark Rutland , "Martin K. Petersen" , Paolo Bonzini , Christian Borntraeger , Christoffer Dall , Dave Kleikamp , Jan Kara , Luis de Bethencourt , Marc Zyngier , Rik van Riel , Matthew Garrett , linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel To: linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1515636190-24061-1-git-send-email-keescook@chromium.org> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org The size of fields within a structure is needed in a few places in the kernel already, and will be needed for the usercopy whitelisting when declaring whitelist regions within structures. This creates a dedicated macro and redefines offsetofend() to use it. Existing usage, ignoring the 1200+ lustre assert uses: $ git grep -E 'sizeof\(\(\((struct )?[a-zA-Z_]+ \*\)0\)->' | \ grep -v staging/lustre | wc -l 65 Signed-off-by: Kees Cook --- include/linux/stddef.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/include/linux/stddef.h b/include/linux/stddef.h index 2181719fd907..998a4ba28eba 100644 --- a/include/linux/stddef.h +++ b/include/linux/stddef.h @@ -20,12 +20,20 @@ enum { #endif /** + * sizeof_field(TYPE, MEMBER) + * + * @TYPE: The structure containing the field of interest + * @MEMBER: The field to return the size of + */ +#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER)) + +/** * offsetofend(TYPE, MEMBER) * * @TYPE: The type of the structure * @MEMBER: The member within the structure to get the end offset of */ #define offsetofend(TYPE, MEMBER) \ - (offsetof(TYPE, MEMBER) + sizeof(((TYPE *)0)->MEMBER)) + (offsetof(TYPE, MEMBER) + sizeof_field(TYPE, MEMBER)) #endif -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org