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![weiping zhang](/assets/img/avatar_default.png)
blkcg policy should keep cpd/pd's alloc_fn and free_fn in pairs, otherwise policy would register fail. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: weiping zhang <zhangweiping@didichuxing.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
1514 lines
38 KiB
C
1514 lines
38 KiB
C
/*
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* Common Block IO controller cgroup interface
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*
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* Based on ideas and code from CFQ, CFS and BFQ:
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* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
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*
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* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
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* Paolo Valente <paolo.valente@unimore.it>
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*
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* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
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* Nauman Rafique <nauman@google.com>
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*
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* For policy-specific per-blkcg data:
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* Copyright (C) 2015 Paolo Valente <paolo.valente@unimore.it>
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* Arianna Avanzini <avanzini.arianna@gmail.com>
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*/
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#include <linux/ioprio.h>
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#include <linux/kdev_t.h>
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#include <linux/module.h>
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#include <linux/sched/signal.h>
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#include <linux/err.h>
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#include <linux/blkdev.h>
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#include <linux/backing-dev.h>
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#include <linux/slab.h>
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#include <linux/genhd.h>
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#include <linux/delay.h>
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#include <linux/atomic.h>
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#include <linux/ctype.h>
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#include <linux/blk-cgroup.h>
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#include "blk.h"
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#define MAX_KEY_LEN 100
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/*
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* blkcg_pol_mutex protects blkcg_policy[] and policy [de]activation.
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* blkcg_pol_register_mutex nests outside of it and synchronizes entire
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* policy [un]register operations including cgroup file additions /
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* removals. Putting cgroup file registration outside blkcg_pol_mutex
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* allows grabbing it from cgroup callbacks.
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*/
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static DEFINE_MUTEX(blkcg_pol_register_mutex);
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static DEFINE_MUTEX(blkcg_pol_mutex);
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struct blkcg blkcg_root;
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EXPORT_SYMBOL_GPL(blkcg_root);
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struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css;
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static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
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static LIST_HEAD(all_blkcgs); /* protected by blkcg_pol_mutex */
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static bool blkcg_policy_enabled(struct request_queue *q,
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const struct blkcg_policy *pol)
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{
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return pol && test_bit(pol->plid, q->blkcg_pols);
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}
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/**
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* blkg_free - free a blkg
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* @blkg: blkg to free
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*
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* Free @blkg which may be partially allocated.
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*/
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static void blkg_free(struct blkcg_gq *blkg)
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{
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int i;
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if (!blkg)
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return;
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for (i = 0; i < BLKCG_MAX_POLS; i++)
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if (blkg->pd[i])
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blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
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if (blkg->blkcg != &blkcg_root)
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blk_exit_rl(blkg->q, &blkg->rl);
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blkg_rwstat_exit(&blkg->stat_ios);
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blkg_rwstat_exit(&blkg->stat_bytes);
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kfree(blkg);
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}
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/**
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* blkg_alloc - allocate a blkg
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* @blkcg: block cgroup the new blkg is associated with
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* @q: request_queue the new blkg is associated with
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* @gfp_mask: allocation mask to use
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*
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* Allocate a new blkg assocating @blkcg and @q.
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*/
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static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q,
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gfp_t gfp_mask)
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{
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struct blkcg_gq *blkg;
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int i;
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/* alloc and init base part */
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blkg = kzalloc_node(sizeof(*blkg), gfp_mask, q->node);
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if (!blkg)
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return NULL;
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if (blkg_rwstat_init(&blkg->stat_bytes, gfp_mask) ||
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blkg_rwstat_init(&blkg->stat_ios, gfp_mask))
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goto err_free;
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blkg->q = q;
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INIT_LIST_HEAD(&blkg->q_node);
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blkg->blkcg = blkcg;
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atomic_set(&blkg->refcnt, 1);
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/* root blkg uses @q->root_rl, init rl only for !root blkgs */
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if (blkcg != &blkcg_root) {
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if (blk_init_rl(&blkg->rl, q, gfp_mask))
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goto err_free;
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blkg->rl.blkg = blkg;
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}
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for (i = 0; i < BLKCG_MAX_POLS; i++) {
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struct blkcg_policy *pol = blkcg_policy[i];
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struct blkg_policy_data *pd;
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if (!blkcg_policy_enabled(q, pol))
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continue;
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/* alloc per-policy data and attach it to blkg */
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pd = pol->pd_alloc_fn(gfp_mask, q->node);
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if (!pd)
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goto err_free;
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blkg->pd[i] = pd;
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pd->blkg = blkg;
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pd->plid = i;
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}
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return blkg;
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err_free:
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blkg_free(blkg);
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return NULL;
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}
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struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
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struct request_queue *q, bool update_hint)
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{
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struct blkcg_gq *blkg;
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/*
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* Hint didn't match. Look up from the radix tree. Note that the
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* hint can only be updated under queue_lock as otherwise @blkg
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* could have already been removed from blkg_tree. The caller is
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* responsible for grabbing queue_lock if @update_hint.
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*/
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blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
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if (blkg && blkg->q == q) {
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if (update_hint) {
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lockdep_assert_held(q->queue_lock);
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rcu_assign_pointer(blkcg->blkg_hint, blkg);
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}
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return blkg;
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}
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return NULL;
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}
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EXPORT_SYMBOL_GPL(blkg_lookup_slowpath);
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/*
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* If @new_blkg is %NULL, this function tries to allocate a new one as
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* necessary using %GFP_NOWAIT. @new_blkg is always consumed on return.
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*/
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static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
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struct request_queue *q,
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struct blkcg_gq *new_blkg)
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{
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struct blkcg_gq *blkg;
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struct bdi_writeback_congested *wb_congested;
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int i, ret;
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WARN_ON_ONCE(!rcu_read_lock_held());
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lockdep_assert_held(q->queue_lock);
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/* blkg holds a reference to blkcg */
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if (!css_tryget_online(&blkcg->css)) {
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ret = -ENODEV;
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goto err_free_blkg;
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}
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wb_congested = wb_congested_get_create(q->backing_dev_info,
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blkcg->css.id,
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GFP_NOWAIT | __GFP_NOWARN);
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if (!wb_congested) {
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ret = -ENOMEM;
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goto err_put_css;
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}
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/* allocate */
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if (!new_blkg) {
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new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT | __GFP_NOWARN);
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if (unlikely(!new_blkg)) {
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ret = -ENOMEM;
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goto err_put_congested;
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}
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}
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blkg = new_blkg;
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blkg->wb_congested = wb_congested;
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/* link parent */
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if (blkcg_parent(blkcg)) {
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blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false);
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if (WARN_ON_ONCE(!blkg->parent)) {
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ret = -ENODEV;
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goto err_put_congested;
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}
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blkg_get(blkg->parent);
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}
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/* invoke per-policy init */
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for (i = 0; i < BLKCG_MAX_POLS; i++) {
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struct blkcg_policy *pol = blkcg_policy[i];
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if (blkg->pd[i] && pol->pd_init_fn)
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pol->pd_init_fn(blkg->pd[i]);
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}
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/* insert */
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spin_lock(&blkcg->lock);
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ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg);
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if (likely(!ret)) {
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hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
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list_add(&blkg->q_node, &q->blkg_list);
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for (i = 0; i < BLKCG_MAX_POLS; i++) {
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struct blkcg_policy *pol = blkcg_policy[i];
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if (blkg->pd[i] && pol->pd_online_fn)
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pol->pd_online_fn(blkg->pd[i]);
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}
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}
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blkg->online = true;
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spin_unlock(&blkcg->lock);
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if (!ret)
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return blkg;
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/* @blkg failed fully initialized, use the usual release path */
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blkg_put(blkg);
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return ERR_PTR(ret);
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err_put_congested:
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wb_congested_put(wb_congested);
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err_put_css:
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css_put(&blkcg->css);
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err_free_blkg:
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blkg_free(new_blkg);
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return ERR_PTR(ret);
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}
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/**
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* blkg_lookup_create - lookup blkg, try to create one if not there
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* @blkcg: blkcg of interest
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* @q: request_queue of interest
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*
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* Lookup blkg for the @blkcg - @q pair. If it doesn't exist, try to
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* create one. blkg creation is performed recursively from blkcg_root such
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* that all non-root blkg's have access to the parent blkg. This function
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* should be called under RCU read lock and @q->queue_lock.
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*
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* Returns pointer to the looked up or created blkg on success, ERR_PTR()
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* value on error. If @q is dead, returns ERR_PTR(-EINVAL). If @q is not
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* dead and bypassing, returns ERR_PTR(-EBUSY).
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*/
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struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
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struct request_queue *q)
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{
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struct blkcg_gq *blkg;
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WARN_ON_ONCE(!rcu_read_lock_held());
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lockdep_assert_held(q->queue_lock);
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/*
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* This could be the first entry point of blkcg implementation and
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* we shouldn't allow anything to go through for a bypassing queue.
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*/
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if (unlikely(blk_queue_bypass(q)))
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return ERR_PTR(blk_queue_dying(q) ? -ENODEV : -EBUSY);
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blkg = __blkg_lookup(blkcg, q, true);
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if (blkg)
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return blkg;
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/*
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* Create blkgs walking down from blkcg_root to @blkcg, so that all
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* non-root blkgs have access to their parents.
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*/
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while (true) {
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struct blkcg *pos = blkcg;
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struct blkcg *parent = blkcg_parent(blkcg);
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while (parent && !__blkg_lookup(parent, q, false)) {
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pos = parent;
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parent = blkcg_parent(parent);
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}
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blkg = blkg_create(pos, q, NULL);
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if (pos == blkcg || IS_ERR(blkg))
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return blkg;
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}
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}
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static void blkg_destroy(struct blkcg_gq *blkg)
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{
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struct blkcg *blkcg = blkg->blkcg;
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struct blkcg_gq *parent = blkg->parent;
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int i;
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lockdep_assert_held(blkg->q->queue_lock);
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lockdep_assert_held(&blkcg->lock);
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/* Something wrong if we are trying to remove same group twice */
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WARN_ON_ONCE(list_empty(&blkg->q_node));
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WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node));
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for (i = 0; i < BLKCG_MAX_POLS; i++) {
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struct blkcg_policy *pol = blkcg_policy[i];
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if (blkg->pd[i] && pol->pd_offline_fn)
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pol->pd_offline_fn(blkg->pd[i]);
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}
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if (parent) {
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blkg_rwstat_add_aux(&parent->stat_bytes, &blkg->stat_bytes);
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blkg_rwstat_add_aux(&parent->stat_ios, &blkg->stat_ios);
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}
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blkg->online = false;
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radix_tree_delete(&blkcg->blkg_tree, blkg->q->id);
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list_del_init(&blkg->q_node);
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hlist_del_init_rcu(&blkg->blkcg_node);
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/*
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* Both setting lookup hint to and clearing it from @blkg are done
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* under queue_lock. If it's not pointing to @blkg now, it never
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* will. Hint assignment itself can race safely.
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*/
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if (rcu_access_pointer(blkcg->blkg_hint) == blkg)
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rcu_assign_pointer(blkcg->blkg_hint, NULL);
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/*
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* Put the reference taken at the time of creation so that when all
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* queues are gone, group can be destroyed.
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*/
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blkg_put(blkg);
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}
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/**
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* blkg_destroy_all - destroy all blkgs associated with a request_queue
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* @q: request_queue of interest
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*
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* Destroy all blkgs associated with @q.
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*/
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static void blkg_destroy_all(struct request_queue *q)
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{
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struct blkcg_gq *blkg, *n;
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lockdep_assert_held(q->queue_lock);
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list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
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struct blkcg *blkcg = blkg->blkcg;
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spin_lock(&blkcg->lock);
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blkg_destroy(blkg);
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spin_unlock(&blkcg->lock);
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}
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q->root_blkg = NULL;
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q->root_rl.blkg = NULL;
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}
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/*
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* A group is RCU protected, but having an rcu lock does not mean that one
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* can access all the fields of blkg and assume these are valid. For
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* example, don't try to follow throtl_data and request queue links.
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*
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* Having a reference to blkg under an rcu allows accesses to only values
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* local to groups like group stats and group rate limits.
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*/
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void __blkg_release_rcu(struct rcu_head *rcu_head)
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{
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struct blkcg_gq *blkg = container_of(rcu_head, struct blkcg_gq, rcu_head);
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/* release the blkcg and parent blkg refs this blkg has been holding */
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css_put(&blkg->blkcg->css);
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if (blkg->parent)
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blkg_put(blkg->parent);
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wb_congested_put(blkg->wb_congested);
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blkg_free(blkg);
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}
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EXPORT_SYMBOL_GPL(__blkg_release_rcu);
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/*
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* The next function used by blk_queue_for_each_rl(). It's a bit tricky
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* because the root blkg uses @q->root_rl instead of its own rl.
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*/
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struct request_list *__blk_queue_next_rl(struct request_list *rl,
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struct request_queue *q)
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{
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struct list_head *ent;
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struct blkcg_gq *blkg;
|
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|
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/*
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* Determine the current blkg list_head. The first entry is
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* root_rl which is off @q->blkg_list and mapped to the head.
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*/
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if (rl == &q->root_rl) {
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ent = &q->blkg_list;
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/* There are no more block groups, hence no request lists */
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if (list_empty(ent))
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return NULL;
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} else {
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blkg = container_of(rl, struct blkcg_gq, rl);
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ent = &blkg->q_node;
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}
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|
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/* walk to the next list_head, skip root blkcg */
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ent = ent->next;
|
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if (ent == &q->root_blkg->q_node)
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ent = ent->next;
|
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if (ent == &q->blkg_list)
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return NULL;
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|
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blkg = container_of(ent, struct blkcg_gq, q_node);
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return &blkg->rl;
|
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}
|
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|
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static int blkcg_reset_stats(struct cgroup_subsys_state *css,
|
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struct cftype *cftype, u64 val)
|
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{
|
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struct blkcg *blkcg = css_to_blkcg(css);
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struct blkcg_gq *blkg;
|
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int i;
|
|
|
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mutex_lock(&blkcg_pol_mutex);
|
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spin_lock_irq(&blkcg->lock);
|
|
|
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/*
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* Note that stat reset is racy - it doesn't synchronize against
|
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* stat updates. This is a debug feature which shouldn't exist
|
|
* anyway. If you get hit by a race, retry.
|
|
*/
|
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hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
|
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blkg_rwstat_reset(&blkg->stat_bytes);
|
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blkg_rwstat_reset(&blkg->stat_ios);
|
|
|
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for (i = 0; i < BLKCG_MAX_POLS; i++) {
|
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struct blkcg_policy *pol = blkcg_policy[i];
|
|
|
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if (blkg->pd[i] && pol->pd_reset_stats_fn)
|
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pol->pd_reset_stats_fn(blkg->pd[i]);
|
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}
|
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}
|
|
|
|
spin_unlock_irq(&blkcg->lock);
|
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mutex_unlock(&blkcg_pol_mutex);
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return 0;
|
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}
|
|
|
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const char *blkg_dev_name(struct blkcg_gq *blkg)
|
|
{
|
|
/* some drivers (floppy) instantiate a queue w/o disk registered */
|
|
if (blkg->q->backing_dev_info->dev)
|
|
return dev_name(blkg->q->backing_dev_info->dev);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_dev_name);
|
|
|
|
/**
|
|
* blkcg_print_blkgs - helper for printing per-blkg data
|
|
* @sf: seq_file to print to
|
|
* @blkcg: blkcg of interest
|
|
* @prfill: fill function to print out a blkg
|
|
* @pol: policy in question
|
|
* @data: data to be passed to @prfill
|
|
* @show_total: to print out sum of prfill return values or not
|
|
*
|
|
* This function invokes @prfill on each blkg of @blkcg if pd for the
|
|
* policy specified by @pol exists. @prfill is invoked with @sf, the
|
|
* policy data and @data and the matching queue lock held. If @show_total
|
|
* is %true, the sum of the return values from @prfill is printed with
|
|
* "Total" label at the end.
|
|
*
|
|
* This is to be used to construct print functions for
|
|
* cftype->read_seq_string method.
|
|
*/
|
|
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
|
|
u64 (*prfill)(struct seq_file *,
|
|
struct blkg_policy_data *, int),
|
|
const struct blkcg_policy *pol, int data,
|
|
bool show_total)
|
|
{
|
|
struct blkcg_gq *blkg;
|
|
u64 total = 0;
|
|
|
|
rcu_read_lock();
|
|
hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
|
|
spin_lock_irq(blkg->q->queue_lock);
|
|
if (blkcg_policy_enabled(blkg->q, pol))
|
|
total += prfill(sf, blkg->pd[pol->plid], data);
|
|
spin_unlock_irq(blkg->q->queue_lock);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
if (show_total)
|
|
seq_printf(sf, "Total %llu\n", (unsigned long long)total);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkcg_print_blkgs);
|
|
|
|
/**
|
|
* __blkg_prfill_u64 - prfill helper for a single u64 value
|
|
* @sf: seq_file to print to
|
|
* @pd: policy private data of interest
|
|
* @v: value to print
|
|
*
|
|
* Print @v to @sf for the device assocaited with @pd.
|
|
*/
|
|
u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v)
|
|
{
|
|
const char *dname = blkg_dev_name(pd->blkg);
|
|
|
|
if (!dname)
|
|
return 0;
|
|
|
|
seq_printf(sf, "%s %llu\n", dname, (unsigned long long)v);
|
|
return v;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blkg_prfill_u64);
|
|
|
|
/**
|
|
* __blkg_prfill_rwstat - prfill helper for a blkg_rwstat
|
|
* @sf: seq_file to print to
|
|
* @pd: policy private data of interest
|
|
* @rwstat: rwstat to print
|
|
*
|
|
* Print @rwstat to @sf for the device assocaited with @pd.
|
|
*/
|
|
u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
|
|
const struct blkg_rwstat *rwstat)
|
|
{
|
|
static const char *rwstr[] = {
|
|
[BLKG_RWSTAT_READ] = "Read",
|
|
[BLKG_RWSTAT_WRITE] = "Write",
|
|
[BLKG_RWSTAT_SYNC] = "Sync",
|
|
[BLKG_RWSTAT_ASYNC] = "Async",
|
|
};
|
|
const char *dname = blkg_dev_name(pd->blkg);
|
|
u64 v;
|
|
int i;
|
|
|
|
if (!dname)
|
|
return 0;
|
|
|
|
for (i = 0; i < BLKG_RWSTAT_NR; i++)
|
|
seq_printf(sf, "%s %s %llu\n", dname, rwstr[i],
|
|
(unsigned long long)atomic64_read(&rwstat->aux_cnt[i]));
|
|
|
|
v = atomic64_read(&rwstat->aux_cnt[BLKG_RWSTAT_READ]) +
|
|
atomic64_read(&rwstat->aux_cnt[BLKG_RWSTAT_WRITE]);
|
|
seq_printf(sf, "%s Total %llu\n", dname, (unsigned long long)v);
|
|
return v;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);
|
|
|
|
/**
|
|
* blkg_prfill_stat - prfill callback for blkg_stat
|
|
* @sf: seq_file to print to
|
|
* @pd: policy private data of interest
|
|
* @off: offset to the blkg_stat in @pd
|
|
*
|
|
* prfill callback for printing a blkg_stat.
|
|
*/
|
|
u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off)
|
|
{
|
|
return __blkg_prfill_u64(sf, pd, blkg_stat_read((void *)pd + off));
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_prfill_stat);
|
|
|
|
/**
|
|
* blkg_prfill_rwstat - prfill callback for blkg_rwstat
|
|
* @sf: seq_file to print to
|
|
* @pd: policy private data of interest
|
|
* @off: offset to the blkg_rwstat in @pd
|
|
*
|
|
* prfill callback for printing a blkg_rwstat.
|
|
*/
|
|
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
|
|
int off)
|
|
{
|
|
struct blkg_rwstat rwstat = blkg_rwstat_read((void *)pd + off);
|
|
|
|
return __blkg_prfill_rwstat(sf, pd, &rwstat);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
|
|
|
|
static u64 blkg_prfill_rwstat_field(struct seq_file *sf,
|
|
struct blkg_policy_data *pd, int off)
|
|
{
|
|
struct blkg_rwstat rwstat = blkg_rwstat_read((void *)pd->blkg + off);
|
|
|
|
return __blkg_prfill_rwstat(sf, pd, &rwstat);
|
|
}
|
|
|
|
/**
|
|
* blkg_print_stat_bytes - seq_show callback for blkg->stat_bytes
|
|
* @sf: seq_file to print to
|
|
* @v: unused
|
|
*
|
|
* To be used as cftype->seq_show to print blkg->stat_bytes.
|
|
* cftype->private must be set to the blkcg_policy.
|
|
*/
|
|
int blkg_print_stat_bytes(struct seq_file *sf, void *v)
|
|
{
|
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
|
|
blkg_prfill_rwstat_field, (void *)seq_cft(sf)->private,
|
|
offsetof(struct blkcg_gq, stat_bytes), true);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_print_stat_bytes);
|
|
|
|
/**
|
|
* blkg_print_stat_bytes - seq_show callback for blkg->stat_ios
|
|
* @sf: seq_file to print to
|
|
* @v: unused
|
|
*
|
|
* To be used as cftype->seq_show to print blkg->stat_ios. cftype->private
|
|
* must be set to the blkcg_policy.
|
|
*/
|
|
int blkg_print_stat_ios(struct seq_file *sf, void *v)
|
|
{
|
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
|
|
blkg_prfill_rwstat_field, (void *)seq_cft(sf)->private,
|
|
offsetof(struct blkcg_gq, stat_ios), true);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_print_stat_ios);
|
|
|
|
static u64 blkg_prfill_rwstat_field_recursive(struct seq_file *sf,
|
|
struct blkg_policy_data *pd,
|
|
int off)
|
|
{
|
|
struct blkg_rwstat rwstat = blkg_rwstat_recursive_sum(pd->blkg,
|
|
NULL, off);
|
|
return __blkg_prfill_rwstat(sf, pd, &rwstat);
|
|
}
|
|
|
|
/**
|
|
* blkg_print_stat_bytes_recursive - recursive version of blkg_print_stat_bytes
|
|
* @sf: seq_file to print to
|
|
* @v: unused
|
|
*/
|
|
int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v)
|
|
{
|
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
|
|
blkg_prfill_rwstat_field_recursive,
|
|
(void *)seq_cft(sf)->private,
|
|
offsetof(struct blkcg_gq, stat_bytes), true);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_print_stat_bytes_recursive);
|
|
|
|
/**
|
|
* blkg_print_stat_ios_recursive - recursive version of blkg_print_stat_ios
|
|
* @sf: seq_file to print to
|
|
* @v: unused
|
|
*/
|
|
int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v)
|
|
{
|
|
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
|
|
blkg_prfill_rwstat_field_recursive,
|
|
(void *)seq_cft(sf)->private,
|
|
offsetof(struct blkcg_gq, stat_ios), true);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_print_stat_ios_recursive);
|
|
|
|
/**
|
|
* blkg_stat_recursive_sum - collect hierarchical blkg_stat
|
|
* @blkg: blkg of interest
|
|
* @pol: blkcg_policy which contains the blkg_stat
|
|
* @off: offset to the blkg_stat in blkg_policy_data or @blkg
|
|
*
|
|
* Collect the blkg_stat specified by @blkg, @pol and @off and all its
|
|
* online descendants and their aux counts. The caller must be holding the
|
|
* queue lock for online tests.
|
|
*
|
|
* If @pol is NULL, blkg_stat is at @off bytes into @blkg; otherwise, it is
|
|
* at @off bytes into @blkg's blkg_policy_data of the policy.
|
|
*/
|
|
u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg,
|
|
struct blkcg_policy *pol, int off)
|
|
{
|
|
struct blkcg_gq *pos_blkg;
|
|
struct cgroup_subsys_state *pos_css;
|
|
u64 sum = 0;
|
|
|
|
lockdep_assert_held(blkg->q->queue_lock);
|
|
|
|
rcu_read_lock();
|
|
blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
|
|
struct blkg_stat *stat;
|
|
|
|
if (!pos_blkg->online)
|
|
continue;
|
|
|
|
if (pol)
|
|
stat = (void *)blkg_to_pd(pos_blkg, pol) + off;
|
|
else
|
|
stat = (void *)blkg + off;
|
|
|
|
sum += blkg_stat_read(stat) + atomic64_read(&stat->aux_cnt);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return sum;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_stat_recursive_sum);
|
|
|
|
/**
|
|
* blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat
|
|
* @blkg: blkg of interest
|
|
* @pol: blkcg_policy which contains the blkg_rwstat
|
|
* @off: offset to the blkg_rwstat in blkg_policy_data or @blkg
|
|
*
|
|
* Collect the blkg_rwstat specified by @blkg, @pol and @off and all its
|
|
* online descendants and their aux counts. The caller must be holding the
|
|
* queue lock for online tests.
|
|
*
|
|
* If @pol is NULL, blkg_rwstat is at @off bytes into @blkg; otherwise, it
|
|
* is at @off bytes into @blkg's blkg_policy_data of the policy.
|
|
*/
|
|
struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg,
|
|
struct blkcg_policy *pol, int off)
|
|
{
|
|
struct blkcg_gq *pos_blkg;
|
|
struct cgroup_subsys_state *pos_css;
|
|
struct blkg_rwstat sum = { };
|
|
int i;
|
|
|
|
lockdep_assert_held(blkg->q->queue_lock);
|
|
|
|
rcu_read_lock();
|
|
blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
|
|
struct blkg_rwstat *rwstat;
|
|
|
|
if (!pos_blkg->online)
|
|
continue;
|
|
|
|
if (pol)
|
|
rwstat = (void *)blkg_to_pd(pos_blkg, pol) + off;
|
|
else
|
|
rwstat = (void *)pos_blkg + off;
|
|
|
|
for (i = 0; i < BLKG_RWSTAT_NR; i++)
|
|
atomic64_add(atomic64_read(&rwstat->aux_cnt[i]) +
|
|
percpu_counter_sum_positive(&rwstat->cpu_cnt[i]),
|
|
&sum.aux_cnt[i]);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return sum;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum);
|
|
|
|
/* Performs queue bypass and policy enabled checks then looks up blkg. */
|
|
static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg,
|
|
const struct blkcg_policy *pol,
|
|
struct request_queue *q)
|
|
{
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
lockdep_assert_held(q->queue_lock);
|
|
|
|
if (!blkcg_policy_enabled(q, pol))
|
|
return ERR_PTR(-EOPNOTSUPP);
|
|
|
|
/*
|
|
* This could be the first entry point of blkcg implementation and
|
|
* we shouldn't allow anything to go through for a bypassing queue.
|
|
*/
|
|
if (unlikely(blk_queue_bypass(q)))
|
|
return ERR_PTR(blk_queue_dying(q) ? -ENODEV : -EBUSY);
|
|
|
|
return __blkg_lookup(blkcg, q, true /* update_hint */);
|
|
}
|
|
|
|
/**
|
|
* blkg_conf_prep - parse and prepare for per-blkg config update
|
|
* @blkcg: target block cgroup
|
|
* @pol: target policy
|
|
* @input: input string
|
|
* @ctx: blkg_conf_ctx to be filled
|
|
*
|
|
* Parse per-blkg config update from @input and initialize @ctx with the
|
|
* result. @ctx->blkg points to the blkg to be updated and @ctx->body the
|
|
* part of @input following MAJ:MIN. This function returns with RCU read
|
|
* lock and queue lock held and must be paired with blkg_conf_finish().
|
|
*/
|
|
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
|
|
char *input, struct blkg_conf_ctx *ctx)
|
|
__acquires(rcu) __acquires(disk->queue->queue_lock)
|
|
{
|
|
struct gendisk *disk;
|
|
struct request_queue *q;
|
|
struct blkcg_gq *blkg;
|
|
struct module *owner;
|
|
unsigned int major, minor;
|
|
int key_len, part, ret;
|
|
char *body;
|
|
|
|
if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2)
|
|
return -EINVAL;
|
|
|
|
body = input + key_len;
|
|
if (!isspace(*body))
|
|
return -EINVAL;
|
|
body = skip_spaces(body);
|
|
|
|
disk = get_gendisk(MKDEV(major, minor), &part);
|
|
if (!disk)
|
|
return -ENODEV;
|
|
if (part) {
|
|
ret = -ENODEV;
|
|
goto fail;
|
|
}
|
|
|
|
q = disk->queue;
|
|
|
|
rcu_read_lock();
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
blkg = blkg_lookup_check(blkcg, pol, q);
|
|
if (IS_ERR(blkg)) {
|
|
ret = PTR_ERR(blkg);
|
|
goto fail_unlock;
|
|
}
|
|
|
|
if (blkg)
|
|
goto success;
|
|
|
|
/*
|
|
* Create blkgs walking down from blkcg_root to @blkcg, so that all
|
|
* non-root blkgs have access to their parents.
|
|
*/
|
|
while (true) {
|
|
struct blkcg *pos = blkcg;
|
|
struct blkcg *parent;
|
|
struct blkcg_gq *new_blkg;
|
|
|
|
parent = blkcg_parent(blkcg);
|
|
while (parent && !__blkg_lookup(parent, q, false)) {
|
|
pos = parent;
|
|
parent = blkcg_parent(parent);
|
|
}
|
|
|
|
/* Drop locks to do new blkg allocation with GFP_KERNEL. */
|
|
spin_unlock_irq(q->queue_lock);
|
|
rcu_read_unlock();
|
|
|
|
new_blkg = blkg_alloc(pos, q, GFP_KERNEL);
|
|
if (unlikely(!new_blkg)) {
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
blkg = blkg_lookup_check(pos, pol, q);
|
|
if (IS_ERR(blkg)) {
|
|
ret = PTR_ERR(blkg);
|
|
goto fail_unlock;
|
|
}
|
|
|
|
if (blkg) {
|
|
blkg_free(new_blkg);
|
|
} else {
|
|
blkg = blkg_create(pos, q, new_blkg);
|
|
if (unlikely(IS_ERR(blkg))) {
|
|
ret = PTR_ERR(blkg);
|
|
goto fail_unlock;
|
|
}
|
|
}
|
|
|
|
if (pos == blkcg)
|
|
goto success;
|
|
}
|
|
success:
|
|
ctx->disk = disk;
|
|
ctx->blkg = blkg;
|
|
ctx->body = body;
|
|
return 0;
|
|
|
|
fail_unlock:
|
|
spin_unlock_irq(q->queue_lock);
|
|
rcu_read_unlock();
|
|
fail:
|
|
owner = disk->fops->owner;
|
|
put_disk(disk);
|
|
module_put(owner);
|
|
/*
|
|
* If queue was bypassing, we should retry. Do so after a
|
|
* short msleep(). It isn't strictly necessary but queue
|
|
* can be bypassing for some time and it's always nice to
|
|
* avoid busy looping.
|
|
*/
|
|
if (ret == -EBUSY) {
|
|
msleep(10);
|
|
ret = restart_syscall();
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_conf_prep);
|
|
|
|
/**
|
|
* blkg_conf_finish - finish up per-blkg config update
|
|
* @ctx: blkg_conf_ctx intiailized by blkg_conf_prep()
|
|
*
|
|
* Finish up after per-blkg config update. This function must be paired
|
|
* with blkg_conf_prep().
|
|
*/
|
|
void blkg_conf_finish(struct blkg_conf_ctx *ctx)
|
|
__releases(ctx->disk->queue->queue_lock) __releases(rcu)
|
|
{
|
|
struct module *owner;
|
|
|
|
spin_unlock_irq(ctx->disk->queue->queue_lock);
|
|
rcu_read_unlock();
|
|
owner = ctx->disk->fops->owner;
|
|
put_disk(ctx->disk);
|
|
module_put(owner);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkg_conf_finish);
|
|
|
|
static int blkcg_print_stat(struct seq_file *sf, void *v)
|
|
{
|
|
struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
|
|
struct blkcg_gq *blkg;
|
|
|
|
rcu_read_lock();
|
|
|
|
hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
|
|
const char *dname;
|
|
struct blkg_rwstat rwstat;
|
|
u64 rbytes, wbytes, rios, wios;
|
|
|
|
dname = blkg_dev_name(blkg);
|
|
if (!dname)
|
|
continue;
|
|
|
|
spin_lock_irq(blkg->q->queue_lock);
|
|
|
|
rwstat = blkg_rwstat_recursive_sum(blkg, NULL,
|
|
offsetof(struct blkcg_gq, stat_bytes));
|
|
rbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_READ]);
|
|
wbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_WRITE]);
|
|
|
|
rwstat = blkg_rwstat_recursive_sum(blkg, NULL,
|
|
offsetof(struct blkcg_gq, stat_ios));
|
|
rios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_READ]);
|
|
wios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_WRITE]);
|
|
|
|
spin_unlock_irq(blkg->q->queue_lock);
|
|
|
|
if (rbytes || wbytes || rios || wios)
|
|
seq_printf(sf, "%s rbytes=%llu wbytes=%llu rios=%llu wios=%llu\n",
|
|
dname, rbytes, wbytes, rios, wios);
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
return 0;
|
|
}
|
|
|
|
static struct cftype blkcg_files[] = {
|
|
{
|
|
.name = "stat",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = blkcg_print_stat,
|
|
},
|
|
{ } /* terminate */
|
|
};
|
|
|
|
static struct cftype blkcg_legacy_files[] = {
|
|
{
|
|
.name = "reset_stats",
|
|
.write_u64 = blkcg_reset_stats,
|
|
},
|
|
{ } /* terminate */
|
|
};
|
|
|
|
/**
|
|
* blkcg_css_offline - cgroup css_offline callback
|
|
* @css: css of interest
|
|
*
|
|
* This function is called when @css is about to go away and responsible
|
|
* for shooting down all blkgs associated with @css. blkgs should be
|
|
* removed while holding both q and blkcg locks. As blkcg lock is nested
|
|
* inside q lock, this function performs reverse double lock dancing.
|
|
*
|
|
* This is the blkcg counterpart of ioc_release_fn().
|
|
*/
|
|
static void blkcg_css_offline(struct cgroup_subsys_state *css)
|
|
{
|
|
struct blkcg *blkcg = css_to_blkcg(css);
|
|
|
|
spin_lock_irq(&blkcg->lock);
|
|
|
|
while (!hlist_empty(&blkcg->blkg_list)) {
|
|
struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first,
|
|
struct blkcg_gq, blkcg_node);
|
|
struct request_queue *q = blkg->q;
|
|
|
|
if (spin_trylock(q->queue_lock)) {
|
|
blkg_destroy(blkg);
|
|
spin_unlock(q->queue_lock);
|
|
} else {
|
|
spin_unlock_irq(&blkcg->lock);
|
|
cpu_relax();
|
|
spin_lock_irq(&blkcg->lock);
|
|
}
|
|
}
|
|
|
|
spin_unlock_irq(&blkcg->lock);
|
|
|
|
wb_blkcg_offline(blkcg);
|
|
}
|
|
|
|
static void blkcg_css_free(struct cgroup_subsys_state *css)
|
|
{
|
|
struct blkcg *blkcg = css_to_blkcg(css);
|
|
int i;
|
|
|
|
mutex_lock(&blkcg_pol_mutex);
|
|
|
|
list_del(&blkcg->all_blkcgs_node);
|
|
|
|
for (i = 0; i < BLKCG_MAX_POLS; i++)
|
|
if (blkcg->cpd[i])
|
|
blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]);
|
|
|
|
mutex_unlock(&blkcg_pol_mutex);
|
|
|
|
kfree(blkcg);
|
|
}
|
|
|
|
static struct cgroup_subsys_state *
|
|
blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
|
|
{
|
|
struct blkcg *blkcg;
|
|
struct cgroup_subsys_state *ret;
|
|
int i;
|
|
|
|
mutex_lock(&blkcg_pol_mutex);
|
|
|
|
if (!parent_css) {
|
|
blkcg = &blkcg_root;
|
|
} else {
|
|
blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
|
|
if (!blkcg) {
|
|
ret = ERR_PTR(-ENOMEM);
|
|
goto unlock;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < BLKCG_MAX_POLS ; i++) {
|
|
struct blkcg_policy *pol = blkcg_policy[i];
|
|
struct blkcg_policy_data *cpd;
|
|
|
|
/*
|
|
* If the policy hasn't been attached yet, wait for it
|
|
* to be attached before doing anything else. Otherwise,
|
|
* check if the policy requires any specific per-cgroup
|
|
* data: if it does, allocate and initialize it.
|
|
*/
|
|
if (!pol || !pol->cpd_alloc_fn)
|
|
continue;
|
|
|
|
cpd = pol->cpd_alloc_fn(GFP_KERNEL);
|
|
if (!cpd) {
|
|
ret = ERR_PTR(-ENOMEM);
|
|
goto free_pd_blkcg;
|
|
}
|
|
blkcg->cpd[i] = cpd;
|
|
cpd->blkcg = blkcg;
|
|
cpd->plid = i;
|
|
if (pol->cpd_init_fn)
|
|
pol->cpd_init_fn(cpd);
|
|
}
|
|
|
|
spin_lock_init(&blkcg->lock);
|
|
INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN);
|
|
INIT_HLIST_HEAD(&blkcg->blkg_list);
|
|
#ifdef CONFIG_CGROUP_WRITEBACK
|
|
INIT_LIST_HEAD(&blkcg->cgwb_list);
|
|
#endif
|
|
list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs);
|
|
|
|
mutex_unlock(&blkcg_pol_mutex);
|
|
return &blkcg->css;
|
|
|
|
free_pd_blkcg:
|
|
for (i--; i >= 0; i--)
|
|
if (blkcg->cpd[i])
|
|
blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]);
|
|
|
|
if (blkcg != &blkcg_root)
|
|
kfree(blkcg);
|
|
unlock:
|
|
mutex_unlock(&blkcg_pol_mutex);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* blkcg_init_queue - initialize blkcg part of request queue
|
|
* @q: request_queue to initialize
|
|
*
|
|
* Called from blk_alloc_queue_node(). Responsible for initializing blkcg
|
|
* part of new request_queue @q.
|
|
*
|
|
* RETURNS:
|
|
* 0 on success, -errno on failure.
|
|
*/
|
|
int blkcg_init_queue(struct request_queue *q)
|
|
{
|
|
struct blkcg_gq *new_blkg, *blkg;
|
|
bool preloaded;
|
|
int ret;
|
|
|
|
new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
|
|
if (!new_blkg)
|
|
return -ENOMEM;
|
|
|
|
preloaded = !radix_tree_preload(GFP_KERNEL);
|
|
|
|
/*
|
|
* Make sure the root blkg exists and count the existing blkgs. As
|
|
* @q is bypassing at this point, blkg_lookup_create() can't be
|
|
* used. Open code insertion.
|
|
*/
|
|
rcu_read_lock();
|
|
spin_lock_irq(q->queue_lock);
|
|
blkg = blkg_create(&blkcg_root, q, new_blkg);
|
|
spin_unlock_irq(q->queue_lock);
|
|
rcu_read_unlock();
|
|
|
|
if (preloaded)
|
|
radix_tree_preload_end();
|
|
|
|
if (IS_ERR(blkg))
|
|
return PTR_ERR(blkg);
|
|
|
|
q->root_blkg = blkg;
|
|
q->root_rl.blkg = blkg;
|
|
|
|
ret = blk_throtl_init(q);
|
|
if (ret) {
|
|
spin_lock_irq(q->queue_lock);
|
|
blkg_destroy_all(q);
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* blkcg_drain_queue - drain blkcg part of request_queue
|
|
* @q: request_queue to drain
|
|
*
|
|
* Called from blk_drain_queue(). Responsible for draining blkcg part.
|
|
*/
|
|
void blkcg_drain_queue(struct request_queue *q)
|
|
{
|
|
lockdep_assert_held(q->queue_lock);
|
|
|
|
/*
|
|
* @q could be exiting and already have destroyed all blkgs as
|
|
* indicated by NULL root_blkg. If so, don't confuse policies.
|
|
*/
|
|
if (!q->root_blkg)
|
|
return;
|
|
|
|
blk_throtl_drain(q);
|
|
}
|
|
|
|
/**
|
|
* blkcg_exit_queue - exit and release blkcg part of request_queue
|
|
* @q: request_queue being released
|
|
*
|
|
* Called from blk_release_queue(). Responsible for exiting blkcg part.
|
|
*/
|
|
void blkcg_exit_queue(struct request_queue *q)
|
|
{
|
|
spin_lock_irq(q->queue_lock);
|
|
blkg_destroy_all(q);
|
|
spin_unlock_irq(q->queue_lock);
|
|
|
|
blk_throtl_exit(q);
|
|
}
|
|
|
|
/*
|
|
* We cannot support shared io contexts, as we have no mean to support
|
|
* two tasks with the same ioc in two different groups without major rework
|
|
* of the main cic data structures. For now we allow a task to change
|
|
* its cgroup only if it's the only owner of its ioc.
|
|
*/
|
|
static int blkcg_can_attach(struct cgroup_taskset *tset)
|
|
{
|
|
struct task_struct *task;
|
|
struct cgroup_subsys_state *dst_css;
|
|
struct io_context *ioc;
|
|
int ret = 0;
|
|
|
|
/* task_lock() is needed to avoid races with exit_io_context() */
|
|
cgroup_taskset_for_each(task, dst_css, tset) {
|
|
task_lock(task);
|
|
ioc = task->io_context;
|
|
if (ioc && atomic_read(&ioc->nr_tasks) > 1)
|
|
ret = -EINVAL;
|
|
task_unlock(task);
|
|
if (ret)
|
|
break;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void blkcg_bind(struct cgroup_subsys_state *root_css)
|
|
{
|
|
int i;
|
|
|
|
mutex_lock(&blkcg_pol_mutex);
|
|
|
|
for (i = 0; i < BLKCG_MAX_POLS; i++) {
|
|
struct blkcg_policy *pol = blkcg_policy[i];
|
|
struct blkcg *blkcg;
|
|
|
|
if (!pol || !pol->cpd_bind_fn)
|
|
continue;
|
|
|
|
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node)
|
|
if (blkcg->cpd[pol->plid])
|
|
pol->cpd_bind_fn(blkcg->cpd[pol->plid]);
|
|
}
|
|
mutex_unlock(&blkcg_pol_mutex);
|
|
}
|
|
|
|
struct cgroup_subsys io_cgrp_subsys = {
|
|
.css_alloc = blkcg_css_alloc,
|
|
.css_offline = blkcg_css_offline,
|
|
.css_free = blkcg_css_free,
|
|
.can_attach = blkcg_can_attach,
|
|
.bind = blkcg_bind,
|
|
.dfl_cftypes = blkcg_files,
|
|
.legacy_cftypes = blkcg_legacy_files,
|
|
.legacy_name = "blkio",
|
|
#ifdef CONFIG_MEMCG
|
|
/*
|
|
* This ensures that, if available, memcg is automatically enabled
|
|
* together on the default hierarchy so that the owner cgroup can
|
|
* be retrieved from writeback pages.
|
|
*/
|
|
.depends_on = 1 << memory_cgrp_id,
|
|
#endif
|
|
};
|
|
EXPORT_SYMBOL_GPL(io_cgrp_subsys);
|
|
|
|
/**
|
|
* blkcg_activate_policy - activate a blkcg policy on a request_queue
|
|
* @q: request_queue of interest
|
|
* @pol: blkcg policy to activate
|
|
*
|
|
* Activate @pol on @q. Requires %GFP_KERNEL context. @q goes through
|
|
* bypass mode to populate its blkgs with policy_data for @pol.
|
|
*
|
|
* Activation happens with @q bypassed, so nobody would be accessing blkgs
|
|
* from IO path. Update of each blkg is protected by both queue and blkcg
|
|
* locks so that holding either lock and testing blkcg_policy_enabled() is
|
|
* always enough for dereferencing policy data.
|
|
*
|
|
* The caller is responsible for synchronizing [de]activations and policy
|
|
* [un]registerations. Returns 0 on success, -errno on failure.
|
|
*/
|
|
int blkcg_activate_policy(struct request_queue *q,
|
|
const struct blkcg_policy *pol)
|
|
{
|
|
struct blkg_policy_data *pd_prealloc = NULL;
|
|
struct blkcg_gq *blkg;
|
|
int ret;
|
|
|
|
if (blkcg_policy_enabled(q, pol))
|
|
return 0;
|
|
|
|
if (q->mq_ops)
|
|
blk_mq_freeze_queue(q);
|
|
else
|
|
blk_queue_bypass_start(q);
|
|
pd_prealloc:
|
|
if (!pd_prealloc) {
|
|
pd_prealloc = pol->pd_alloc_fn(GFP_KERNEL, q->node);
|
|
if (!pd_prealloc) {
|
|
ret = -ENOMEM;
|
|
goto out_bypass_end;
|
|
}
|
|
}
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
list_for_each_entry(blkg, &q->blkg_list, q_node) {
|
|
struct blkg_policy_data *pd;
|
|
|
|
if (blkg->pd[pol->plid])
|
|
continue;
|
|
|
|
pd = pol->pd_alloc_fn(GFP_NOWAIT | __GFP_NOWARN, q->node);
|
|
if (!pd)
|
|
swap(pd, pd_prealloc);
|
|
if (!pd) {
|
|
spin_unlock_irq(q->queue_lock);
|
|
goto pd_prealloc;
|
|
}
|
|
|
|
blkg->pd[pol->plid] = pd;
|
|
pd->blkg = blkg;
|
|
pd->plid = pol->plid;
|
|
if (pol->pd_init_fn)
|
|
pol->pd_init_fn(pd);
|
|
}
|
|
|
|
__set_bit(pol->plid, q->blkcg_pols);
|
|
ret = 0;
|
|
|
|
spin_unlock_irq(q->queue_lock);
|
|
out_bypass_end:
|
|
if (q->mq_ops)
|
|
blk_mq_unfreeze_queue(q);
|
|
else
|
|
blk_queue_bypass_end(q);
|
|
if (pd_prealloc)
|
|
pol->pd_free_fn(pd_prealloc);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkcg_activate_policy);
|
|
|
|
/**
|
|
* blkcg_deactivate_policy - deactivate a blkcg policy on a request_queue
|
|
* @q: request_queue of interest
|
|
* @pol: blkcg policy to deactivate
|
|
*
|
|
* Deactivate @pol on @q. Follows the same synchronization rules as
|
|
* blkcg_activate_policy().
|
|
*/
|
|
void blkcg_deactivate_policy(struct request_queue *q,
|
|
const struct blkcg_policy *pol)
|
|
{
|
|
struct blkcg_gq *blkg;
|
|
|
|
if (!blkcg_policy_enabled(q, pol))
|
|
return;
|
|
|
|
if (q->mq_ops)
|
|
blk_mq_freeze_queue(q);
|
|
else
|
|
blk_queue_bypass_start(q);
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
__clear_bit(pol->plid, q->blkcg_pols);
|
|
|
|
list_for_each_entry(blkg, &q->blkg_list, q_node) {
|
|
/* grab blkcg lock too while removing @pd from @blkg */
|
|
spin_lock(&blkg->blkcg->lock);
|
|
|
|
if (blkg->pd[pol->plid]) {
|
|
if (pol->pd_offline_fn)
|
|
pol->pd_offline_fn(blkg->pd[pol->plid]);
|
|
pol->pd_free_fn(blkg->pd[pol->plid]);
|
|
blkg->pd[pol->plid] = NULL;
|
|
}
|
|
|
|
spin_unlock(&blkg->blkcg->lock);
|
|
}
|
|
|
|
spin_unlock_irq(q->queue_lock);
|
|
|
|
if (q->mq_ops)
|
|
blk_mq_unfreeze_queue(q);
|
|
else
|
|
blk_queue_bypass_end(q);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkcg_deactivate_policy);
|
|
|
|
/**
|
|
* blkcg_policy_register - register a blkcg policy
|
|
* @pol: blkcg policy to register
|
|
*
|
|
* Register @pol with blkcg core. Might sleep and @pol may be modified on
|
|
* successful registration. Returns 0 on success and -errno on failure.
|
|
*/
|
|
int blkcg_policy_register(struct blkcg_policy *pol)
|
|
{
|
|
struct blkcg *blkcg;
|
|
int i, ret;
|
|
|
|
mutex_lock(&blkcg_pol_register_mutex);
|
|
mutex_lock(&blkcg_pol_mutex);
|
|
|
|
/* find an empty slot */
|
|
ret = -ENOSPC;
|
|
for (i = 0; i < BLKCG_MAX_POLS; i++)
|
|
if (!blkcg_policy[i])
|
|
break;
|
|
if (i >= BLKCG_MAX_POLS)
|
|
goto err_unlock;
|
|
|
|
/* Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs */
|
|
if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) ||
|
|
(!pol->pd_alloc_fn ^ !pol->pd_free_fn))
|
|
goto err_unlock;
|
|
|
|
/* register @pol */
|
|
pol->plid = i;
|
|
blkcg_policy[pol->plid] = pol;
|
|
|
|
/* allocate and install cpd's */
|
|
if (pol->cpd_alloc_fn) {
|
|
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
|
|
struct blkcg_policy_data *cpd;
|
|
|
|
cpd = pol->cpd_alloc_fn(GFP_KERNEL);
|
|
if (!cpd)
|
|
goto err_free_cpds;
|
|
|
|
blkcg->cpd[pol->plid] = cpd;
|
|
cpd->blkcg = blkcg;
|
|
cpd->plid = pol->plid;
|
|
pol->cpd_init_fn(cpd);
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&blkcg_pol_mutex);
|
|
|
|
/* everything is in place, add intf files for the new policy */
|
|
if (pol->dfl_cftypes)
|
|
WARN_ON(cgroup_add_dfl_cftypes(&io_cgrp_subsys,
|
|
pol->dfl_cftypes));
|
|
if (pol->legacy_cftypes)
|
|
WARN_ON(cgroup_add_legacy_cftypes(&io_cgrp_subsys,
|
|
pol->legacy_cftypes));
|
|
mutex_unlock(&blkcg_pol_register_mutex);
|
|
return 0;
|
|
|
|
err_free_cpds:
|
|
if (pol->cpd_free_fn) {
|
|
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
|
|
if (blkcg->cpd[pol->plid]) {
|
|
pol->cpd_free_fn(blkcg->cpd[pol->plid]);
|
|
blkcg->cpd[pol->plid] = NULL;
|
|
}
|
|
}
|
|
}
|
|
blkcg_policy[pol->plid] = NULL;
|
|
err_unlock:
|
|
mutex_unlock(&blkcg_pol_mutex);
|
|
mutex_unlock(&blkcg_pol_register_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkcg_policy_register);
|
|
|
|
/**
|
|
* blkcg_policy_unregister - unregister a blkcg policy
|
|
* @pol: blkcg policy to unregister
|
|
*
|
|
* Undo blkcg_policy_register(@pol). Might sleep.
|
|
*/
|
|
void blkcg_policy_unregister(struct blkcg_policy *pol)
|
|
{
|
|
struct blkcg *blkcg;
|
|
|
|
mutex_lock(&blkcg_pol_register_mutex);
|
|
|
|
if (WARN_ON(blkcg_policy[pol->plid] != pol))
|
|
goto out_unlock;
|
|
|
|
/* kill the intf files first */
|
|
if (pol->dfl_cftypes)
|
|
cgroup_rm_cftypes(pol->dfl_cftypes);
|
|
if (pol->legacy_cftypes)
|
|
cgroup_rm_cftypes(pol->legacy_cftypes);
|
|
|
|
/* remove cpds and unregister */
|
|
mutex_lock(&blkcg_pol_mutex);
|
|
|
|
if (pol->cpd_free_fn) {
|
|
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
|
|
if (blkcg->cpd[pol->plid]) {
|
|
pol->cpd_free_fn(blkcg->cpd[pol->plid]);
|
|
blkcg->cpd[pol->plid] = NULL;
|
|
}
|
|
}
|
|
}
|
|
blkcg_policy[pol->plid] = NULL;
|
|
|
|
mutex_unlock(&blkcg_pol_mutex);
|
|
out_unlock:
|
|
mutex_unlock(&blkcg_pol_register_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blkcg_policy_unregister);
|