/* * 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: %pF -> %pf 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 %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 }; int __init closure_debug_init(void) { closure_debug = debugfs_create_file("closures", 0400, bcache_debug, NULL, &debug_ops); return IS_ERR_OR_NULL(closure_debug); } #endif MODULE_AUTHOR("Kent Overstreet <koverstreet@google.com>"); MODULE_LICENSE("GPL");