From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 06/16] blkcg: implement bio_associate_blkcg() Date: Tue, 6 Jan 2015 14:29:07 -0500 Message-ID: <1420572557-11572-7-git-send-email-tj@kernel.org> References: <1420572557-11572-1-git-send-email-tj@kernel.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=ANkOYfneLHXiHwQO8K7A7Spevgtbwebykks/DNH4EOI=; b=0zGTzf9MHKFGZtRMQHDg2pgoF2vOztY76zhl00xEXMWxaXOfWUYo5Dof7FA6f47uJC 3yST+0IWTLpYWTtanlvHdTzvS0uw/NR2PY0mJcc9xQvlUlrE4wB7hKPXbIgcqoi5GmdI uGxNzE8ngLZ5dn1lICloP/X6eFTonRADrUyJGEtm0eKZjXbcuANKnHKBY+krHi0U8Cok 7CszZ4Q5Ugwi+CWGQ++MDxpkWYpkrEICS8LY4WYo0iiWCXnp+5WlXKebE2t0PNul69Yq tbLjEpLzlpKIm0vWA+CUlvvaD1KV17BhYN5+EEFIVjwq0T5e9CWMm0UTzMGuxbz1XuiO /pQw== In-Reply-To: <1420572557-11572-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.cz, Tejun Heo 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(-) diff --git a/block/bio.c b/block/bio.c index a1e0b00..89aeae6 100644 --- a/block/bio.c +++ b/block/bio.c @@ -2015,6 +2015,28 @@ struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_ 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 @@ -2032,7 +2054,7 @@ int bio_associate_current(struct bio *bio) { struct io_context *ioc; - if (bio->bi_ioc) + if (bio->bi_css) return -EBUSY; ioc = current->io_context; diff --git a/include/linux/bio.h b/include/linux/bio.h index efead0b..0e863e7 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -475,9 +475,12 @@ extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int); 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 */ -- 2.1.0