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207 lines
4.5 KiB
207 lines
4.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Asynchronous refcounty things |
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* |
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* Copyright 2010, 2011 Kent Overstreet <[email protected]> |
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* Copyright 2012 Google, Inc. |
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*/ |
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#include <linux/debugfs.h> |
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#include <linux/module.h> |
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#include <linux/seq_file.h> |
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#include <linux/sched/debug.h> |
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#include "closure.h" |
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static inline void closure_put_after_sub(struct closure *cl, int flags) |
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{ |
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int r = flags & CLOSURE_REMAINING_MASK; |
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BUG_ON(flags & CLOSURE_GUARD_MASK); |
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BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR)); |
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if (!r) { |
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if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) { |
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atomic_set(&cl->remaining, |
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CLOSURE_REMAINING_INITIALIZER); |
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closure_queue(cl); |
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} else { |
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struct closure *parent = cl->parent; |
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closure_fn *destructor = cl->fn; |
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closure_debug_destroy(cl); |
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if (destructor) |
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destructor(cl); |
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if (parent) |
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closure_put(parent); |
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} |
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} |
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} |
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/* For clearing flags with the same atomic op as a put */ |
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void closure_sub(struct closure *cl, int v) |
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{ |
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closure_put_after_sub(cl, atomic_sub_return(v, &cl->remaining)); |
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} |
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/* |
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* closure_put - decrement a closure's refcount |
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*/ |
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void closure_put(struct closure *cl) |
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{ |
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closure_put_after_sub(cl, atomic_dec_return(&cl->remaining)); |
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} |
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/* |
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* closure_wake_up - wake up all closures on a wait list, without memory barrier |
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*/ |
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void __closure_wake_up(struct closure_waitlist *wait_list) |
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{ |
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struct llist_node *list; |
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struct closure *cl, *t; |
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struct llist_node *reverse = NULL; |
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list = llist_del_all(&wait_list->list); |
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/* We first reverse the list to preserve FIFO ordering and fairness */ |
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reverse = llist_reverse_order(list); |
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/* Then do the wakeups */ |
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llist_for_each_entry_safe(cl, t, reverse, list) { |
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closure_set_waiting(cl, 0); |
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closure_sub(cl, CLOSURE_WAITING + 1); |
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} |
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} |
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/** |
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* closure_wait - add a closure to a waitlist |
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* @waitlist: will own a ref on @cl, which will be released when |
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* closure_wake_up() is called on @waitlist. |
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* @cl: closure pointer. |
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* |
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*/ |
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bool closure_wait(struct closure_waitlist *waitlist, struct closure *cl) |
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{ |
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if (atomic_read(&cl->remaining) & CLOSURE_WAITING) |
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return false; |
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closure_set_waiting(cl, _RET_IP_); |
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atomic_add(CLOSURE_WAITING + 1, &cl->remaining); |
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llist_add(&cl->list, &waitlist->list); |
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return true; |
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} |
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struct closure_syncer { |
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struct task_struct *task; |
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int done; |
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}; |
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static void closure_sync_fn(struct closure *cl) |
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{ |
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struct closure_syncer *s = cl->s; |
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struct task_struct *p; |
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rcu_read_lock(); |
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p = READ_ONCE(s->task); |
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s->done = 1; |
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wake_up_process(p); |
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rcu_read_unlock(); |
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} |
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void __sched __closure_sync(struct closure *cl) |
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{ |
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struct closure_syncer s = { .task = current }; |
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cl->s = &s; |
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continue_at(cl, closure_sync_fn, NULL); |
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while (1) { |
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set_current_state(TASK_UNINTERRUPTIBLE); |
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if (s.done) |
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break; |
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schedule(); |
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} |
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__set_current_state(TASK_RUNNING); |
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} |
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#ifdef CONFIG_BCACHE_CLOSURES_DEBUG |
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static LIST_HEAD(closure_list); |
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static DEFINE_SPINLOCK(closure_list_lock); |
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void closure_debug_create(struct closure *cl) |
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{ |
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unsigned long flags; |
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BUG_ON(cl->magic == CLOSURE_MAGIC_ALIVE); |
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cl->magic = CLOSURE_MAGIC_ALIVE; |
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spin_lock_irqsave(&closure_list_lock, flags); |
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list_add(&cl->all, &closure_list); |
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spin_unlock_irqrestore(&closure_list_lock, flags); |
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} |
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void closure_debug_destroy(struct closure *cl) |
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{ |
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unsigned long flags; |
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BUG_ON(cl->magic != CLOSURE_MAGIC_ALIVE); |
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cl->magic = CLOSURE_MAGIC_DEAD; |
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spin_lock_irqsave(&closure_list_lock, flags); |
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list_del(&cl->all); |
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spin_unlock_irqrestore(&closure_list_lock, flags); |
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} |
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static struct dentry *closure_debug; |
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static int debug_show(struct seq_file *f, void *data) |
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{ |
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struct closure *cl; |
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spin_lock_irq(&closure_list_lock); |
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list_for_each_entry(cl, &closure_list, all) { |
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int r = atomic_read(&cl->remaining); |
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seq_printf(f, "%p: %pS -> %pS p %p r %i ", |
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cl, (void *) cl->ip, cl->fn, cl->parent, |
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r & CLOSURE_REMAINING_MASK); |
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seq_printf(f, "%s%s\n", |
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test_bit(WORK_STRUCT_PENDING_BIT, |
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work_data_bits(&cl->work)) ? "Q" : "", |
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r & CLOSURE_RUNNING ? "R" : ""); |
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if (r & CLOSURE_WAITING) |
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seq_printf(f, " W %pS\n", |
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(void *) cl->waiting_on); |
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seq_printf(f, "\n"); |
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} |
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spin_unlock_irq(&closure_list_lock); |
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return 0; |
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} |
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DEFINE_SHOW_ATTRIBUTE(debug); |
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void __init closure_debug_init(void) |
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{ |
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if (!IS_ERR_OR_NULL(bcache_debug)) |
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/* |
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* it is unnecessary to check return value of |
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* debugfs_create_file(), we should not care |
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* about this. |
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*/ |
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closure_debug = debugfs_create_file( |
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"closures", 0400, bcache_debug, NULL, &debug_fops); |
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} |
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#endif |
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MODULE_AUTHOR("Kent Overstreet <[email protected]>"); |
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MODULE_LICENSE("GPL");
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