v4.19.13 snapshot.
diff --git a/drivers/md/bcache/closure.c b/drivers/md/bcache/closure.c
new file mode 100644
index 0000000..73f5319
--- /dev/null
+++ b/drivers/md/bcache/closure.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Asynchronous refcounty things
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/sched/debug.h>
+
+#include "closure.h"
+
+static inline void closure_put_after_sub(struct closure *cl, int flags)
+{
+ int r = flags & CLOSURE_REMAINING_MASK;
+
+ BUG_ON(flags & CLOSURE_GUARD_MASK);
+ BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR));
+
+ if (!r) {
+ if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
+ atomic_set(&cl->remaining,
+ CLOSURE_REMAINING_INITIALIZER);
+ closure_queue(cl);
+ } else {
+ struct closure *parent = cl->parent;
+ closure_fn *destructor = cl->fn;
+
+ closure_debug_destroy(cl);
+
+ if (destructor)
+ destructor(cl);
+
+ if (parent)
+ closure_put(parent);
+ }
+ }
+}
+
+/* For clearing flags with the same atomic op as a put */
+void closure_sub(struct closure *cl, int v)
+{
+ closure_put_after_sub(cl, atomic_sub_return(v, &cl->remaining));
+}
+EXPORT_SYMBOL(closure_sub);
+
+/*
+ * closure_put - decrement a closure's refcount
+ */
+void closure_put(struct closure *cl)
+{
+ closure_put_after_sub(cl, atomic_dec_return(&cl->remaining));
+}
+EXPORT_SYMBOL(closure_put);
+
+/*
+ * closure_wake_up - wake up all closures on a wait list, without memory barrier
+ */
+void __closure_wake_up(struct closure_waitlist *wait_list)
+{
+ struct llist_node *list;
+ struct closure *cl, *t;
+ struct llist_node *reverse = NULL;
+
+ list = llist_del_all(&wait_list->list);
+
+ /* We first reverse the list to preserve FIFO ordering and fairness */
+ reverse = llist_reverse_order(list);
+
+ /* Then do the wakeups */
+ llist_for_each_entry_safe(cl, t, reverse, list) {
+ closure_set_waiting(cl, 0);
+ closure_sub(cl, CLOSURE_WAITING + 1);
+ }
+}
+EXPORT_SYMBOL(__closure_wake_up);
+
+/**
+ * closure_wait - add a closure to a waitlist
+ * @waitlist: will own a ref on @cl, which will be released when
+ * closure_wake_up() is called on @waitlist.
+ * @cl: closure pointer.
+ *
+ */
+bool closure_wait(struct closure_waitlist *waitlist, struct closure *cl)
+{
+ if (atomic_read(&cl->remaining) & CLOSURE_WAITING)
+ return false;
+
+ closure_set_waiting(cl, _RET_IP_);
+ atomic_add(CLOSURE_WAITING + 1, &cl->remaining);
+ llist_add(&cl->list, &waitlist->list);
+
+ return true;
+}
+EXPORT_SYMBOL(closure_wait);
+
+struct closure_syncer {
+ struct task_struct *task;
+ int done;
+};
+
+static void closure_sync_fn(struct closure *cl)
+{
+ cl->s->done = 1;
+ wake_up_process(cl->s->task);
+}
+
+void __sched __closure_sync(struct closure *cl)
+{
+ struct closure_syncer s = { .task = current };
+
+ cl->s = &s;
+ continue_at(cl, closure_sync_fn, NULL);
+
+ while (1) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (s.done)
+ break;
+ schedule();
+ }
+
+ __set_current_state(TASK_RUNNING);
+}
+EXPORT_SYMBOL(__closure_sync);
+
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+
+static LIST_HEAD(closure_list);
+static DEFINE_SPINLOCK(closure_list_lock);
+
+void closure_debug_create(struct closure *cl)
+{
+ unsigned long flags;
+
+ BUG_ON(cl->magic == CLOSURE_MAGIC_ALIVE);
+ cl->magic = CLOSURE_MAGIC_ALIVE;
+
+ spin_lock_irqsave(&closure_list_lock, flags);
+ list_add(&cl->all, &closure_list);
+ spin_unlock_irqrestore(&closure_list_lock, flags);
+}
+EXPORT_SYMBOL(closure_debug_create);
+
+void closure_debug_destroy(struct closure *cl)
+{
+ unsigned long flags;
+
+ BUG_ON(cl->magic != CLOSURE_MAGIC_ALIVE);
+ cl->magic = CLOSURE_MAGIC_DEAD;
+
+ spin_lock_irqsave(&closure_list_lock, flags);
+ list_del(&cl->all);
+ spin_unlock_irqrestore(&closure_list_lock, flags);
+}
+EXPORT_SYMBOL(closure_debug_destroy);
+
+static struct dentry *closure_debug;
+
+static int debug_seq_show(struct seq_file *f, void *data)
+{
+ struct closure *cl;
+
+ spin_lock_irq(&closure_list_lock);
+
+ list_for_each_entry(cl, &closure_list, all) {
+ int r = atomic_read(&cl->remaining);
+
+ seq_printf(f, "%p: %pS -> %pS p %p r %i ",
+ cl, (void *) cl->ip, cl->fn, cl->parent,
+ r & CLOSURE_REMAINING_MASK);
+
+ seq_printf(f, "%s%s\n",
+ test_bit(WORK_STRUCT_PENDING_BIT,
+ work_data_bits(&cl->work)) ? "Q" : "",
+ r & CLOSURE_RUNNING ? "R" : "");
+
+ if (r & CLOSURE_WAITING)
+ seq_printf(f, " W %pS\n",
+ (void *) cl->waiting_on);
+
+ seq_printf(f, "\n");
+ }
+
+ spin_unlock_irq(&closure_list_lock);
+ return 0;
+}
+
+static int debug_seq_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, debug_seq_show, NULL);
+}
+
+static const struct file_operations debug_ops = {
+ .owner = THIS_MODULE,
+ .open = debug_seq_open,
+ .read = seq_read,
+ .release = single_release
+};
+
+void __init closure_debug_init(void)
+{
+ if (!IS_ERR_OR_NULL(bcache_debug))
+ /*
+ * it is unnecessary to check return value of
+ * debugfs_create_file(), we should not care
+ * about this.
+ */
+ closure_debug = debugfs_create_file(
+ "closures", 0400, bcache_debug, NULL, &debug_ops);
+}
+#endif
+
+MODULE_AUTHOR("Kent Overstreet <koverstreet@google.com>");
+MODULE_LICENSE("GPL");