From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755183Ab2IZJtW (ORCPT ); Wed, 26 Sep 2012 05:49:22 -0400 Received: from mail-ey0-f174.google.com ([209.85.215.174]:55821 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754823Ab2IZJtL (ORCPT ); Wed, 26 Sep 2012 05:49:11 -0400 From: Maxim Levitsky To: Andrew Morton Cc: Alex Dubov , linux-kernel@vger.kernel.org, Tejun Heo , Maxim Levitsky Subject: [PATCH 1/2] scatterlist: add sg_nents Date: Wed, 26 Sep 2012 11:49:00 +0200 Message-Id: <1348652941-31899-2-git-send-email-maximlevitsky@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1348652941-31899-1-git-send-email-maximlevitsky@gmail.com> References: <1348652941-31899-1-git-send-email-maximlevitsky@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Useful helper to know the number of entries in scatterlist. Signed-off-by: Maxim Levitsky --- include/linux/scatterlist.h | 1 + lib/scatterlist.c | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 7b600da..4bd6c06 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -201,6 +201,7 @@ static inline void *sg_virt(struct scatterlist *sg) return page_address(sg_page(sg)) + sg->offset; } +int sg_nents(struct scatterlist *sg); struct scatterlist *sg_next(struct scatterlist *); struct scatterlist *sg_last(struct scatterlist *s, unsigned int); void sg_init_table(struct scatterlist *, unsigned int); diff --git a/lib/scatterlist.c b/lib/scatterlist.c index e76d85c..5cd9cdc 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -39,6 +39,28 @@ struct scatterlist *sg_next(struct scatterlist *sg) EXPORT_SYMBOL(sg_next); /** + * sg_nents - return total count of entries in scatterlist + * @sg: The scatterlist + * + * Description: + * Allows to know how many entries are in sg, taking into acount + * chaining as well + * + **/ +int sg_nents(struct scatterlist *sg) +{ + int nents = 0; + while (sg) { + nents++; + sg = sg_next(sg); + } + + return nents; +} +EXPORT_SYMBOL(sg_nents); + + +/** * sg_last - return the last scatterlist entry in a list * @sgl: First entry in the scatterlist * @nents: Number of entries in the scatterlist -- 1.7.9.5