Merge tag 'nds32-for-linus-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / mm / backing-dev.c

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 347cc83..2e5d3df 100644 (file)
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -359,15 +359,8 @@ static void wb_shutdown(struct bdi_writeback *wb)
        spin_lock_bh(&wb->work_lock);
        if (!test_and_clear_bit(WB_registered, &wb->state)) {
                spin_unlock_bh(&wb->work_lock);
-               /*
-                * Wait for wb shutdown to finish if someone else is just
-                * running wb_shutdown(). Otherwise we could proceed to wb /
-                * bdi destruction before wb_shutdown() is finished.
-                */
-               wait_on_bit(&wb->state, WB_shutting_down, TASK_UNINTERRUPTIBLE);
                return;
        }
-       set_bit(WB_shutting_down, &wb->state);
        spin_unlock_bh(&wb->work_lock);
 
        cgwb_remove_from_bdi_list(wb);
@@ -379,12 +372,6 @@ static void wb_shutdown(struct bdi_writeback *wb)
        mod_delayed_work(bdi_wq, &wb->dwork, 0);
        flush_delayed_work(&wb->dwork);
        WARN_ON(!list_empty(&wb->work_list));
-       /*
-        * Make sure bit gets cleared after shutdown is finished. Matches with
-        * the barrier provided by test_and_clear_bit() above.
-        */
-       smp_wmb();
-       clear_and_wake_up_bit(WB_shutting_down, &wb->state);
 }
 
 static void wb_exit(struct bdi_writeback *wb)
@@ -508,10 +495,12 @@ static void cgwb_release_workfn(struct work_struct *work)
        struct bdi_writeback *wb = container_of(work, struct bdi_writeback,
                                                release_work);
 
+       mutex_lock(&wb->bdi->cgwb_release_mutex);
        wb_shutdown(wb);
 
        css_put(wb->memcg_css);
        css_put(wb->blkcg_css);
+       mutex_unlock(&wb->bdi->cgwb_release_mutex);
 
        fprop_local_destroy_percpu(&wb->memcg_completions);
        percpu_ref_exit(&wb->refcnt);
@@ -697,6 +686,7 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi)
 
        INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC);
        bdi->cgwb_congested_tree = RB_ROOT;
+       mutex_init(&bdi->cgwb_release_mutex);
 
        ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
        if (!ret) {
@@ -717,7 +707,10 @@ static void cgwb_bdi_unregister(struct backing_dev_info *bdi)
        spin_lock_irq(&cgwb_lock);
        radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0)
                cgwb_kill(*slot);
+       spin_unlock_irq(&cgwb_lock);
 
+       mutex_lock(&bdi->cgwb_release_mutex);
+       spin_lock_irq(&cgwb_lock);
        while (!list_empty(&bdi->wb_list)) {
                wb = list_first_entry(&bdi->wb_list, struct bdi_writeback,
                                      bdi_node);
@@ -726,6 +719,7 @@ static void cgwb_bdi_unregister(struct backing_dev_info *bdi)
                spin_lock_irq(&cgwb_lock);
        }
        spin_unlock_irq(&cgwb_lock);
+       mutex_unlock(&bdi->cgwb_release_mutex);
 }
 
 /**