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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 JS |
28 | { |
29 | struct rb_node **p = &head->head.rb_node; | |
30 | struct rb_node *parent = NULL; | |
1f5a2479 | 31 | struct timerqueue_node *ptr; |
87de5ac7 JS |
32 | |
33 | /* Make sure we don't add nodes that are already added */ | |
34 | WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node)); | |
35 | ||
36 | while (*p) { | |
37 | parent = *p; | |
1f5a2479 | 38 | ptr = rb_entry(parent, struct timerqueue_node, node); |
2456e855 | 39 | if (node->expires < ptr->expires) |
87de5ac7 JS |
40 | p = &(*p)->rb_left; |
41 | else | |
42 | p = &(*p)->rb_right; | |
43 | } | |
44 | rb_link_node(&node->node, parent, p); | |
45 | rb_insert_color(&node->node, &head->head); | |
46 | ||
2456e855 | 47 | if (!head->next || node->expires < head->next->expires) { |
87de5ac7 | 48 | head->next = node; |
c320642e TG |
49 | return true; |
50 | } | |
51 | return false; | |
87de5ac7 | 52 | } |
9bb99b14 | 53 | EXPORT_SYMBOL_GPL(timerqueue_add); |
87de5ac7 JS |
54 | |
55 | /** | |
1f5a2479 | 56 | * timerqueue_del - Removes a timer from the timerqueue. |
87de5ac7 | 57 | * |
1f5a2479 | 58 | * @head: head of timerqueue |
87de5ac7 JS |
59 | * @node: timer node to be removed |
60 | * | |
9f4533cd TG |
61 | * Removes the timer node from the timerqueue. Returns true if the queue is |
62 | * not empty after the remove. | |
87de5ac7 | 63 | */ |
c320642e | 64 | bool timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node) |
87de5ac7 JS |
65 | { |
66 | WARN_ON_ONCE(RB_EMPTY_NODE(&node->node)); | |
67 | ||
68 | /* update next pointer */ | |
69 | if (head->next == node) { | |
70 | struct rb_node *rbn = rb_next(&node->node); | |
71 | ||
d852d394 | 72 | head->next = rb_entry_safe(rbn, struct timerqueue_node, node); |
87de5ac7 JS |
73 | } |
74 | rb_erase(&node->node, &head->head); | |
75 | RB_CLEAR_NODE(&node->node); | |
c320642e | 76 | return head->next != NULL; |
87de5ac7 | 77 | } |
9bb99b14 | 78 | EXPORT_SYMBOL_GPL(timerqueue_del); |
87de5ac7 | 79 | |
87de5ac7 | 80 | /** |
1f5a2479 | 81 | * timerqueue_iterate_next - Returns the timer after the provided timer |
87de5ac7 JS |
82 | * |
83 | * @node: Pointer to a timer. | |
84 | * | |
85 | * Provides the timer that is after the given node. This is used, when | |
86 | * necessary, to iterate through the list of timers in a timer list | |
87 | * without modifying the list. | |
88 | */ | |
1f5a2479 | 89 | struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node) |
87de5ac7 JS |
90 | { |
91 | struct rb_node *next; | |
92 | ||
93 | if (!node) | |
94 | return NULL; | |
95 | next = rb_next(&node->node); | |
96 | if (!next) | |
97 | return NULL; | |
1f5a2479 | 98 | return container_of(next, struct timerqueue_node, node); |
87de5ac7 | 99 | } |
9bb99b14 | 100 | EXPORT_SYMBOL_GPL(timerqueue_iterate_next); |