wangchdo commented on code in PR #17517: URL: https://github.com/apache/nuttx/pull/17517#discussion_r2625261010
########## sched/hrtimer/hrtimer_cancel.c: ########## @@ -0,0 +1,184 @@ +/**************************************************************************** + * sched/hrtimer/hrtimer_cancel.c + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> +#include <nuttx/arch.h> +#include <nuttx/clock.h> + +#include <errno.h> + +#include "hrtimer/hrtimer.h" + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: hrtimer_cancel + * + * Description: + * Cancel a high-resolution timer. + * + * If the timer is currently armed, it will be removed from the active + * hrtimer red-black tree and will not be executed. + * + * If the timer callback is currently executing, the timer will be marked + * as canceled. The running callback is allowed to complete, but it will + * not be re-armed or executed again. + * + * If the canceled timer was the earliest (head) timer in the tree, the + * expiration of the underlying hardware timer will be updated to: + * + * 1. The expiration time of the next earliest timer, or + * 2. A safe default expiration if no timers remain. + * + * This function is non-blocking and does not wait for a running callback + * to finish. + * + * Input Parameters: + * hrtimer - Pointer to the high-resolution timer instance to cancel. + * + * Returned Value: + * OK (0) on success; a negated errno value on failure. + * + * Assumptions/Notes: + * - This function acquires the global hrtimer spinlock to protect the + * red-black tree and timer state. + * - The caller must ensure that the timer structure is not freed until + * it is guaranteed that any running callback has returned. + ****************************************************************************/ + +int hrtimer_cancel(FAR hrtimer_t *hrtimer) +{ + FAR hrtimer_t *first; + irqstate_t flags; + int ret = OK; + + DEBUGASSERT(hrtimer != NULL); + + /* Enter critical section to protect the hrtimer tree and state */ + + flags = spin_lock_irqsave(&g_hrtimer_spinlock); + + /* Capture the current earliest timer before removal */ + + first = (FAR hrtimer_t *)RB_MIN(hrtimer_tree_s, &g_hrtimer_tree); + + switch (hrtimer->state) + { + case HRTIMER_STATE_ARMED: + { + /* Remove the timer from the active tree */ + + RB_REMOVE(hrtimer_tree_s, &g_hrtimer_tree, &hrtimer->node); + hrtimer->state = HRTIMER_STATE_INACTIVE; + break; + } + + case HRTIMER_STATE_RUNNING: + { + /* The callback is currently executing. + * + * Mark the timer as canceled so it will not be re-armed or + * executed again. The running callback is allowed to complete. + * + * NOTE: The timer node is expected to have already been removed + * from the tree when the callback started executing. + */ + + hrtimer->state = HRTIMER_STATE_CANCELED; + break; + } + + case HRTIMER_STATE_INACTIVE: + case HRTIMER_STATE_CANCELED: + default: + { + ret = -EINVAL; + break; + } + } + + /* If the canceled timer was the earliest one, update the hardware timer */ + + if ((ret == OK) && (first == hrtimer)) + { + first = (FAR hrtimer_t *)RB_MIN(hrtimer_tree_s, &g_hrtimer_tree); + if (first != NULL) + { + ret = hrtimer_starttimer(first->expired); + } + } + + /* Leave critical section */ + + spin_unlock_irqrestore(&g_hrtimer_spinlock, flags); + return ret; +} + +/**************************************************************************** + * Name: hrtimer_cancel_sync + * + * Description: + * Cancel a high-resolution timer and wait synchronously until the timer + * becomes inactive. + * + * This function first calls hrtimer_cancel() to request cancellation of + * the timer. If the timer callback is currently executing, this function + * will wait until the callback has completed and the timer state has + * transitioned to HRTIMER_STATE_INACTIVE. + * + * This function may sleep and must not be called from interrupt context. + * + * Input Parameters: + * hrtimer - Pointer to the high-resolution timer instance to cancel. + * + * Returned Value: + * OK (0) on success; a negated errno value on failure. + * + ****************************************************************************/ + +int hrtimer_cancel_sync(FAR hrtimer_t *hrtimer) +{ + int ret; + + DEBUGASSERT(hrtimer != NULL); + + ret = hrtimer_cancel(hrtimer); + if (ret < 0) + { + return ret; + } + + /* Wait until the timer becomes inactive */ + + while (hrtimer->state != HRTIMER_STATE_INACTIVE) + { + nxsched_ticksleep(5); Review Comment: Done -- This is an automated message from the Apache Git Service. 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