From cd1604fab4f95f7cfc227d3955fd7ae14da61f38 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 5 Mar 2012 13:15:06 -0800 Subject: blkcg: factor out blkio_group creation Currently both blk-throttle and cfq-iosched implement their own blkio_group creation code in throtl_get_tg() and cfq_get_cfqg(). This patch factors out the common code into blkg_lookup_create(), which returns ERR_PTR value so that transitional failures due to queue bypass can be distinguished from other failures. * New plkio_policy_ops methods blkio_alloc_group_fn() and blkio_link_group_fn added. Both are transitional and will be removed once the blkg management code is fully moved into blk-cgroup.c. * blkio_alloc_group_fn() allocates policy-specific blkg which is usually a larger data structure with blkg as the first entry and intiailizes it. Note that initialization of blkg proper, including percpu stats, is responsibility of blk-cgroup proper. Note that default config (weight, bps...) initialization is done from this method; otherwise, we end up violating locking order between blkcg and q locks via blkcg_get_CONF() functions. * blkio_link_group_fn() is called under queue_lock and responsible for linking the blkg to the queue. blkcg side is handled by blk-cgroup proper. * The common blkg creation function is named blkg_lookup_create() and blkiocg_lookup_group() is renamed to blkg_lookup() for consistency. Also, throtl / cfq related functions are similarly [re]named for consistency. This simplifies blkcg policy implementations and enables further cleanup. -v2: Vivek noticed that blkg_lookup_create() incorrectly tested blk_queue_dead() instead of blk_queue_bypass() leading a user of the function ending up creating a new blkg on bypassing queue. This is a bug introduced while relocating bypass patches before this one. Fixed. -v3: ERR_PTR patch folded into this one. @for_root added to blkg_lookup_create() to allow creating root group on a bypassed queue during elevator switch. Signed-off-by: Tejun Heo Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/cfq.h | 8 -------- 1 file changed, 8 deletions(-) (limited to 'block/cfq.h') diff --git a/block/cfq.h b/block/cfq.h index 343b78a61df3..398760194e11 100644 --- a/block/cfq.h +++ b/block/cfq.h @@ -67,12 +67,6 @@ static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, direction, sync); } -static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, - struct blkio_group *blkg, struct request_queue *q, dev_t dev) -{ - blkiocg_add_blkio_group(blkcg, blkg, q, dev, BLKIO_POLICY_PROP); -} - static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg) { return blkiocg_del_blkio_group(blkg); @@ -105,8 +99,6 @@ static inline void cfq_blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes, bool direction, bool sync) {} static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) {} -static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, - struct blkio_group *blkg, struct request_queue *q, dev_t dev) {} static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; -- cgit v1.2.3