From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752980AbaKQVQY (ORCPT ); Mon, 17 Nov 2014 16:16:24 -0500 Received: from mail-qg0-f50.google.com ([209.85.192.50]:49219 "EHLO mail-qg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752929AbaKQVQW (ORCPT ); Mon, 17 Nov 2014 16:16:22 -0500 Date: Mon, 17 Nov 2014 16:16:19 -0500 From: Tejun Heo To: Jens Axboe Cc: linux-kernel@vger.kernel.org, Vivek Goyal Subject: [PATCH block/for-next 4/4] block: implement bio_associate_blkcg() Message-ID: <20141117211619.GG23126@htj.dyndns.org> References: <20141117211321.GD23126@htj.dyndns.org> <20141117211357.GE23126@htj.dyndns.org> <20141117211546.GF23126@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141117211546.GF23126@htj.dyndns.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, a bio can only be associated with the io_context and blkcg of %current using bio_associate_current(). This is too restrictive for cgroup writeback support. Implement bio_associate_blkcg() which associates a bio with the specified blkcg. bio_associate_blkcg() leaves the io_context unassociated. bio_associate_current() is updated so that it considers a bio as already associated if it has a blkcg_css, instead of an io_context, associated with it. Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Vivek Goyal --- block/bio.c | 24 +++++++++++++++++++++++- include/linux/bio.h | 3 +++ 2 files changed, 26 insertions(+), 1 deletion(-) --- a/block/bio.c +++ b/block/bio.c @@ -1981,6 +1981,28 @@ struct bio_set *bioset_create_nobvec(uns EXPORT_SYMBOL(bioset_create_nobvec); #ifdef CONFIG_BLK_CGROUP + +/** + * bio_associate_blkcg - associate a bio with the specified blkcg + * @bio: target bio + * @blkcg_css: the css of the blkcg to associate + * + * Associate @bio with the blkcg specified by @blkcg_css. Block layer will + * treat @bio as if it were issued by a task which belongs to the blkcg. + * + * This function takes an extra reference of @blkcg_css which will be put + * when @bio is released. The caller must own @bio and is responsible for + * synchronizing calls to this function. + */ +int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) +{ + if (unlikely(bio->bi_css)) + return -EBUSY; + css_get(blkcg_css); + bio->bi_css = blkcg_css; + return 0; +} + /** * bio_associate_current - associate a bio with %current * @bio: target bio @@ -1998,7 +2020,7 @@ int bio_associate_current(struct bio *bi { struct io_context *ioc; - if (bio->bi_ioc) + if (bio->bi_css) return -EBUSY; ioc = current->io_context; --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -470,9 +470,12 @@ extern void bvec_free(mempool_t *, struc extern unsigned int bvec_nr_vecs(unsigned short idx); #ifdef CONFIG_BLK_CGROUP +int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css); int bio_associate_current(struct bio *bio); void bio_disassociate_task(struct bio *bio); #else /* CONFIG_BLK_CGROUP */ +static inline int bio_associate_blkcg(struct bio *bio, + struct cgroup_subsys_state *blkcg_css) { return 0; } static inline int bio_associate_current(struct bio *bio) { return -ENOENT; } static inline void bio_disassociate_task(struct bio *bio) { } #endif /* CONFIG_BLK_CGROUP */