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4c199a93a2
Empty nodes have no color. We can make use of this property to simplify the code emitted by the RB_EMPTY_NODE and RB_CLEAR_NODE macros. Also, we can get rid of the rb_init_node function which had been introduced by commit88d19cf379("timers: Add rb_init_node() to allow for stack allocated rb nodes") to avoid some issue with the empty node's color not being initialized. I'm not sure what the RB_EMPTY_NODE checks in rb_prev() / rb_next() are doing there, though. axboe introduced them in commit10fd48f237("rbtree: fixed reversed RB_EMPTY_NODE and rb_next/prev"). The way I see it, the 'empty node' abstraction is only used by rbtree users to flag nodes that they haven't inserted in any rbtree, so asking the predecessor or successor of such nodes doesn't make any sense. One final rb_init_node() caller was recently added in sysctl code to implement faster sysctl name lookups. This code doesn't make use of RB_EMPTY_NODE at all, and from what I could see it only called rb_init_node() under the mistaken assumption that such initialization was required before node insertion. [sfr@canb.auug.org.au: fix net/ceph/osd_client.c build] Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
50 lines
1.1 KiB
C
50 lines
1.1 KiB
C
#ifndef _LINUX_TIMERQUEUE_H
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#define _LINUX_TIMERQUEUE_H
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#include <linux/rbtree.h>
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#include <linux/ktime.h>
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struct timerqueue_node {
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struct rb_node node;
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ktime_t expires;
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};
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struct timerqueue_head {
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struct rb_root head;
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struct timerqueue_node *next;
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};
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extern void timerqueue_add(struct timerqueue_head *head,
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struct timerqueue_node *node);
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extern void timerqueue_del(struct timerqueue_head *head,
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struct timerqueue_node *node);
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extern struct timerqueue_node *timerqueue_iterate_next(
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struct timerqueue_node *node);
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/**
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* timerqueue_getnext - Returns the timer with the earliest expiration time
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*
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* @head: head of timerqueue
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*
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* Returns a pointer to the timer node that has the
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* earliest expiration time.
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*/
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static inline
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struct timerqueue_node *timerqueue_getnext(struct timerqueue_head *head)
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{
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return head->next;
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}
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static inline void timerqueue_init(struct timerqueue_node *node)
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{
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RB_CLEAR_NODE(&node->node);
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}
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static inline void timerqueue_init_head(struct timerqueue_head *head)
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{
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head->head = RB_ROOT;
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head->next = NULL;
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}
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#endif /* _LINUX_TIMERQUEUE_H */
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