summaryrefslogtreecommitdiffstats
path: root/drivers/md/bcache/closure.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/md/bcache/closure.c')
-rw-r--r--drivers/md/bcache/closure.c345
1 files changed, 345 insertions, 0 deletions
diff --git a/drivers/md/bcache/closure.c b/drivers/md/bcache/closure.c
new file mode 100644
index 000000000000..bd05a9a8c7cf
--- /dev/null
+++ b/drivers/md/bcache/closure.c
@@ -0,0 +1,345 @@
+/*
+ * 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 "closure.h"
+
+void closure_queue(struct closure *cl)
+{
+ struct workqueue_struct *wq = cl->wq;
+ if (wq) {
+ INIT_WORK(&cl->work, cl->work.func);
+ BUG_ON(!queue_work(wq, &cl->work));
+ } else
+ cl->fn(cl);
+}
+EXPORT_SYMBOL_GPL(closure_queue);
+
+#define CL_FIELD(type, field) \
+ case TYPE_ ## type: \
+ return &container_of(cl, struct type, cl)->field
+
+static struct closure_waitlist *closure_waitlist(struct closure *cl)
+{
+ switch (cl->type) {
+ CL_FIELD(closure_with_waitlist, wait);
+ CL_FIELD(closure_with_waitlist_and_timer, wait);
+ default:
+ return NULL;
+ }
+}
+
+static struct timer_list *closure_timer(struct closure *cl)
+{
+ switch (cl->type) {
+ CL_FIELD(closure_with_timer, timer);
+ CL_FIELD(closure_with_waitlist_and_timer, timer);
+ default:
+ return NULL;
+ }
+}
+
+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|CLOSURE_BLOCKING)));
+
+ /* Must deliver precisely one wakeup */
+ if (r == 1 && (flags & CLOSURE_SLEEPING))
+ wake_up_process(cl->task);
+
+ if (!r) {
+ if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
+ /* CLOSURE_BLOCKING might be set - clear it */
+ atomic_set(&cl->remaining,
+ CLOSURE_REMAINING_INITIALIZER);
+ closure_queue(cl);
+ } else {
+ struct closure *parent = cl->parent;
+ struct closure_waitlist *wait = closure_waitlist(cl);
+
+ closure_debug_destroy(cl);
+
+ atomic_set(&cl->remaining, -1);
+
+ if (wait)
+ closure_wake_up(wait);
+
+ if (cl->fn)
+ cl->fn(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_GPL(closure_sub);
+
+void closure_put(struct closure *cl)
+{
+ closure_put_after_sub(cl, atomic_dec_return(&cl->remaining));
+}
+EXPORT_SYMBOL_GPL(closure_put);
+
+static void set_waiting(struct closure *cl, unsigned long f)
+{
+#ifdef CONFIG_BCACHE_CLOSURES_DEBUG
+ cl->waiting_on = f;
+#endif
+}
+
+void __closure_wake_up(struct closure_waitlist *wait_list)
+{
+ struct llist_node *list;
+ struct closure *cl;
+ struct llist_node *reverse = NULL;
+
+ list = llist_del_all(&wait_list->list);
+
+ /* We first reverse the list to preserve FIFO ordering and fairness */
+
+ while (list) {
+ struct llist_node *t = list;
+ list = llist_next(list);
+
+ t->next = reverse;
+ reverse = t;
+ }
+
+ /* Then do the wakeups */
+
+ while (reverse) {
+ cl = container_of(reverse, struct closure, list);
+ reverse = llist_next(reverse);
+
+ set_waiting(cl, 0);
+ closure_sub(cl, CLOSURE_WAITING + 1);
+ }
+}
+EXPORT_SYMBOL_GPL(__closure_wake_up);
+
+bool closure_wait(struct closure_waitlist *list, struct closure *cl)
+{
+ if (atomic_read(&cl->remaining) & CLOSURE_WAITING)
+ return false;
+
+ set_waiting(cl, _RET_IP_);
+ atomic_add(CLOSURE_WAITING + 1, &cl->remaining);
+ llist_add(&cl->list, &list->list);
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(closure_wait);
+
+/**
+ * closure_sync() - sleep until a closure a closure has nothing left to wait on
+ *
+ * Sleeps until the refcount hits 1 - the thread that's running the closure owns
+ * the last refcount.
+ */
+void closure_sync(struct closure *cl)
+{
+ while (1) {
+ __closure_start_sleep(cl);
+ closure_set_ret_ip(cl);
+
+ if ((atomic_read(&cl->remaining) &
+ CLOSURE_REMAINING_MASK) == 1)
+ break;
+
+ schedule();
+ }
+
+ __closure_end_sleep(cl);
+}
+EXPORT_SYMBOL_GPL(closure_sync);
+
+/**
+ * closure_trylock() - try to acquire the closure, without waiting
+ * @cl: closure to lock
+ *
+ * Returns true if the closure was succesfully locked.
+ */
+bool closure_trylock(struct closure *cl, struct closure *parent)
+{
+ if (atomic_cmpxchg(&cl->remaining, -1,
+ CLOSURE_REMAINING_INITIALIZER) != -1)
+ return false;
+
+ closure_set_ret_ip(cl);
+
+ smp_mb();
+ cl->parent = parent;
+ if (parent)
+ closure_get(parent);
+
+ closure_debug_create(cl);
+ return true;
+}
+EXPORT_SYMBOL_GPL(closure_trylock);
+
+void __closure_lock(struct closure *cl, struct closure *parent,
+ struct closure_waitlist *wait_list)
+{
+ struct closure wait;
+ closure_init_stack(&wait);
+
+ while (1) {
+ if (closure_trylock(cl, parent))
+ return;
+
+ closure_wait_event_sync(wait_list, &wait,
+ atomic_read(&cl->remaining) == -1);
+ }
+}
+EXPORT_SYMBOL_GPL(__closure_lock);
+
+static void closure_delay_timer_fn(unsigned long data)
+{
+ struct closure *cl = (struct closure *) data;
+ closure_sub(cl, CLOSURE_TIMER + 1);
+}
+
+void do_closure_timer_init(struct closure *cl)
+{
+ struct timer_list *timer = closure_timer(cl);
+
+ init_timer(timer);
+ timer->data = (unsigned long) cl;
+ timer->function = closure_delay_timer_fn;
+}
+EXPORT_SYMBOL_GPL(do_closure_timer_init);
+
+bool __closure_delay(struct closure *cl, unsigned long delay,
+ struct timer_list *timer)
+{
+ if (atomic_read(&cl->remaining) & CLOSURE_TIMER)
+ return false;
+
+ BUG_ON(timer_pending(timer));
+
+ timer->expires = jiffies + delay;
+
+ atomic_add(CLOSURE_TIMER + 1, &cl->remaining);
+ add_timer(timer);
+ return true;
+}
+EXPORT_SYMBOL_GPL(__closure_delay);
+
+void __closure_flush(struct closure *cl, struct timer_list *timer)
+{
+ if (del_timer(timer))
+ closure_sub(cl, CLOSURE_TIMER + 1);
+}
+EXPORT_SYMBOL_GPL(__closure_flush);
+
+void __closure_flush_sync(struct closure *cl, struct timer_list *timer)
+{
+ if (del_timer_sync(timer))
+ closure_sub(cl, CLOSURE_TIMER + 1);
+}
+EXPORT_SYMBOL_GPL(__closure_flush_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_GPL(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_GPL(closure_debug_destroy);
+
+static struct dentry *debug;
+
+#define work_data_bits(work) ((unsigned long *)(&(work)->data))
+
+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: %pF -> %pf p %p r %i ",
+ cl, (void *) cl->ip, cl->fn, cl->parent,
+ r & CLOSURE_REMAINING_MASK);
+
+ seq_printf(f, "%s%s%s%s%s%s\n",
+ test_bit(WORK_STRUCT_PENDING,
+ work_data_bits(&cl->work)) ? "Q" : "",
+ r & CLOSURE_RUNNING ? "R" : "",
+ r & CLOSURE_BLOCKING ? "B" : "",
+ r & CLOSURE_STACK ? "S" : "",
+ r & CLOSURE_SLEEPING ? "Sl" : "",
+ r & CLOSURE_TIMER ? "T" : "");
+
+ if (r & CLOSURE_WAITING)
+ seq_printf(f, " W %pF\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)
+{
+ debug = debugfs_create_file("closures", 0400, NULL, NULL, &debug_ops);
+}
+
+#endif
+
+MODULE_AUTHOR("Kent Overstreet <koverstreet@google.com>");
+MODULE_LICENSE("GPL");