git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From cdd86c17d2e3bb1b2f119ee722c632e2f7ef3d30 Mon Sep 17 00:00:00 2001
   2 From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
   3 Date: Sat, 11 Mar 2023 10:34:32 +0100
   4 Subject: Revert "blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()"
   5
   6 From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
   7
   8 This reverts commit bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a which is
   9 commit f1c006f1c6850c14040f8337753a63119bba39b9 upstream.
  10
  11 It is reported to cause problems, as only 2 of the 3 patch series were
  12 applied to the stable branches.
  13
  14 Reported-by: Mike Cloaked <mike.cloaked@gmail.com>
  15 Reported-by: Eric Biggers <ebiggers@kernel.org>
  16 Cc: Yu Kuai <yukuai3@huawei.com>
  17 Cc: Tejun Heo <tj@kernel.org>
  18 Cc: Christoph Hellwig <hch@lst.de>
  19 Cc: Jens Axboe <axboe@kernel.dk>
  20 Cc: Sasha Levin <sashal@kernel.org>
  21 Link: https://bugzilla.kernel.org/show_bug.cgi?id=217174
  22 Link: https://lore.kernel.org/r/ZAuPkCn49urWBN5P@sol.localdomain
  23 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25 ---
  26  block/blk-cgroup.c     |   35 ++++++-----------------------------
  27  include/linux/blkdev.h |    1 -
  28  2 files changed, 6 insertions(+), 30 deletions(-)
  29
  30 --- a/block/blk-cgroup.c
  31 +++ b/block/blk-cgroup.c
  32 @@ -118,32 +118,16 @@ static void blkg_free_workfn(struct work
  33  {
  34         struct blkcg_gq *blkg = container_of(work, struct blkcg_gq,
  35                                              free_work);
  36 -       struct request_queue *q = blkg->q;
  37         int i;
  38
  39 -       /*
  40 -        * pd_free_fn() can also be called from blkcg_deactivate_policy(),
  41 -        * in order to make sure pd_free_fn() is called in order, the deletion
  42 -        * of the list blkg->q_node is delayed to here from blkg_destroy(), and
  43 -        * blkcg_mutex is used to synchronize blkg_free_workfn() and
  44 -        * blkcg_deactivate_policy().
  45 -        */
  46 -       if (q)
  47 -               mutex_lock(&q->blkcg_mutex);
  48 -
  49         for (i = 0; i < BLKCG_MAX_POLS; i++)
  50                 if (blkg->pd[i])
  51                         blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
  52
  53         if (blkg->parent)
  54                 blkg_put(blkg->parent);
  55 -
  56 -       if (q) {
  57 -               list_del_init(&blkg->q_node);
  58 -               mutex_unlock(&q->blkcg_mutex);
  59 -               blk_put_queue(q);
  60 -       }
  61 -
  62 +       if (blkg->q)
  63 +               blk_put_queue(blkg->q);
  64         free_percpu(blkg->iostat_cpu);
  65         percpu_ref_exit(&blkg->refcnt);
  66         kfree(blkg);
  67 @@ -474,14 +458,9 @@ static void blkg_destroy(struct blkcg_gq
  68         lockdep_assert_held(&blkg->q->queue_lock);
  69         lockdep_assert_held(&blkcg->lock);
  70
  71 -       /*
  72 -        * blkg stays on the queue list until blkg_free_workfn(), see details in
  73 -        * blkg_free_workfn(), hence this function can be called from
  74 -        * blkcg_destroy_blkgs() first and again from blkg_destroy_all() before
  75 -        * blkg_free_workfn().
  76 -        */
  77 -       if (hlist_unhashed(&blkg->blkcg_node))
  78 -               return;
  79 +       /* Something wrong if we are trying to remove same group twice */
  80 +       WARN_ON_ONCE(list_empty(&blkg->q_node));
  81 +       WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node));
  82
  83         for (i = 0; i < BLKCG_MAX_POLS; i++) {
  84                 struct blkcg_policy *pol = blkcg_policy[i];
  85 @@ -493,6 +472,7 @@ static void blkg_destroy(struct blkcg_gq
  86         blkg->online = false;
  87
  88         radix_tree_delete(&blkcg->blkg_tree, blkg->q->id);
  89 +       list_del_init(&blkg->q_node);
  90         hlist_del_init_rcu(&blkg->blkcg_node);
  91
  92         /*
  93 @@ -1293,7 +1273,6 @@ int blkcg_init_disk(struct gendisk *disk
  94         int ret;
  95
  96         INIT_LIST_HEAD(&q->blkg_list);
  97 -       mutex_init(&q->blkcg_mutex);
  98
  99         new_blkg = blkg_alloc(&blkcg_root, disk, GFP_KERNEL);
 100         if (!new_blkg)
 101 @@ -1531,7 +1510,6 @@ void blkcg_deactivate_policy(struct requ
 102         if (queue_is_mq(q))
 103                 blk_mq_freeze_queue(q);
 104
 105 -       mutex_lock(&q->blkcg_mutex);
 106         spin_lock_irq(&q->queue_lock);
 107
 108         __clear_bit(pol->plid, q->blkcg_pols);
 109 @@ -1550,7 +1528,6 @@ void blkcg_deactivate_policy(struct requ
 110         }
 111
 112         spin_unlock_irq(&q->queue_lock);
 113 -       mutex_unlock(&q->blkcg_mutex);
 114
 115         if (queue_is_mq(q))
 116                 blk_mq_unfreeze_queue(q);
 117 --- a/include/linux/blkdev.h
 118 +++ b/include/linux/blkdev.h
 119 @@ -484,7 +484,6 @@ struct request_queue {
 120         DECLARE_BITMAP          (blkcg_pols, BLKCG_MAX_POLS);
 121         struct blkcg_gq         *root_blkg;
 122         struct list_head        blkg_list;
 123 -       struct mutex            blkcg_mutex;
 124  #endif
 125
 126         struct queue_limits     limits;