Commit | Line | Data |
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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
87de5ac7 | 2 | /* |
1f5a2479 | 3 | * Generic Timer-queue |
87de5ac7 | 4 | * |
1f5a2479 | 5 | * Manages a simple queue of timers, ordered by expiration time. |
87de5ac7 JS |
6 | * Uses rbtrees for quick list adds and expiration. |
7 | * | |
8 | * NOTE: All of the following functions need to be serialized | |
25985edc | 9 | * to avoid races. No locking is done by this library code. |
87de5ac7 JS |
10 | */ |
11 | ||
50af5ead | 12 | #include <linux/bug.h> |
1f5a2479 | 13 | #include <linux/timerqueue.h> |
87de5ac7 | 14 | #include <linux/rbtree.h> |
8bc3bcc9 | 15 | #include <linux/export.h> |
87de5ac7 JS |
16 | |
17 | /** | |
1f5a2479 | 18 | * timerqueue_add - Adds timer to timerqueue. |
87de5ac7 | 19 | * |
1f5a2479 | 20 | * @head: head of timerqueue |
87de5ac7 JS |
21 | * @node: timer node to be added |
22 | * | |
9f4533cd TG |
23 | * Adds the timer node to the timerqueue, sorted by the node's expires |
24 | * value. Returns true if the newly added timer is the first expiring timer in | |
25 | * the queue. | |
87de5ac7 | 26 | */ |
c320642e | 27 | bool timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node) |
87de5ac7 | 28 | { |
511885d7 | 29 | struct rb_node **p = &head->rb_root.rb_root.rb_node; |
87de5ac7 | 30 | struct rb_node *parent = NULL; |
511885d7 DB |
31 | struct timerqueue_node *ptr; |
32 | bool leftmost = true; | |
87de5ac7 JS |
33 | |
34 | /* Make sure we don't add nodes that are already added */ | |
35 | WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node)); | |
36 | ||
37 | while (*p) { | |
38 | parent = *p; | |
1f5a2479 | 39 | ptr = rb_entry(parent, struct timerqueue_node, node); |
511885d7 | 40 | if (node->expires < ptr->expires) { |
87de5ac7 | 41 | p = &(*p)->rb_left; |
511885d7 | 42 | } else { |
87de5ac7 | 43 | p = &(*p)->rb_right; |
511885d7 DB |
44 | leftmost = false; |
45 | } | |
87de5ac7 JS |
46 | } |
47 | rb_link_node(&node->node, parent, p); | |
511885d7 | 48 | rb_insert_color_cached(&node->node, &head->rb_root, leftmost); |
87de5ac7 | 49 | |
511885d7 | 50 | return leftmost; |
87de5ac7 | 51 | } |
9bb99b14 | 52 | EXPORT_SYMBOL_GPL(timerqueue_add); |
87de5ac7 JS |
53 | |
54 | /** | |
1f5a2479 | 55 | * timerqueue_del - Removes a timer from the timerqueue. |
87de5ac7 | 56 | * |
1f5a2479 | 57 | * @head: head of timerqueue |
87de5ac7 JS |
58 | * @node: timer node to be removed |
59 | * | |
9f4533cd TG |
60 | * Removes the timer node from the timerqueue. Returns true if the queue is |
61 | * not empty after the remove. | |
87de5ac7 | 62 | */ |
c320642e | 63 | bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node) |
87de5ac7 JS |
64 | { |
65 | WARN_ON_ONCE(RB_EMPTY_NODE(&node->node)); | |
66 | ||
511885d7 | 67 | rb_erase_cached(&node->node, &head->rb_root); |
87de5ac7 | 68 | RB_CLEAR_NODE(&node->node); |
511885d7 DB |
69 | |
70 | return !RB_EMPTY_ROOT(&head->rb_root.rb_root); | |
87de5ac7 | 71 | } |
9bb99b14 | 72 | EXPORT_SYMBOL_GPL(timerqueue_del); |
87de5ac7 | 73 | |
87de5ac7 | 74 | /** |
1f5a2479 | 75 | * timerqueue_iterate_next - Returns the timer after the provided timer |
87de5ac7 JS |
76 | * |
77 | * @node: Pointer to a timer. | |
78 | * | |
79 | * Provides the timer that is after the given node. This is used, when | |
80 | * necessary, to iterate through the list of timers in a timer list | |
81 | * without modifying the list. | |
82 | */ | |
1f5a2479 | 83 | struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node) |
87de5ac7 JS |
84 | { |
85 | struct rb_node *next; | |
86 | ||
87 | if (!node) | |
88 | return NULL; | |
89 | next = rb_next(&node->node); | |
90 | if (!next) | |
91 | return NULL; | |
1f5a2479 | 92 | return container_of(next, struct timerqueue_node, node); |
87de5ac7 | 93 | } |
9bb99b14 | 94 | EXPORT_SYMBOL_GPL(timerqueue_iterate_next); |