478 lines
14 KiB
C
478 lines
14 KiB
C
/****************************************************************************
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* net/utils/net_lock.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <unistd.h>
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#include <sched.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <time.h>
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#include <nuttx/irq.h>
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#include <nuttx/clock.h>
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#include <nuttx/semaphore.h>
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#include <nuttx/sched.h>
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#include <nuttx/mm/iob.h>
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#include <nuttx/net/net.h>
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#include "utils/utils.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define NO_HOLDER (INVALID_PROCESS_ID)
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static rmutex_t g_netlock = NXRMUTEX_INITIALIZER;
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: _net_timedwait
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****************************************************************************/
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static int
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_net_timedwait(sem_t *sem, bool interruptible, unsigned int timeout)
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{
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unsigned int count;
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irqstate_t flags;
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int blresult;
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int ret;
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flags = enter_critical_section(); /* No interrupts */
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sched_lock(); /* No context switches */
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/* Release the network lock, remembering my count. net_breaklock will
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* return a negated value if the caller does not hold the network lock.
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*/
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blresult = net_breaklock(&count);
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/* Now take the semaphore, waiting if so requested. */
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if (timeout != UINT_MAX)
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{
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/* Wait until we get the lock or until the timeout expires */
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if (interruptible)
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{
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ret = nxsem_tickwait(sem, MSEC2TICK(timeout));
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}
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else
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{
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ret = nxsem_tickwait_uninterruptible(sem, MSEC2TICK(timeout));
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}
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}
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else
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{
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/* Wait as long as necessary to get the lock */
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if (interruptible)
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{
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ret = nxsem_wait(sem);
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}
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else
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{
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ret = nxsem_wait_uninterruptible(sem);
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}
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}
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/* Recover the network lock at the proper count (if we held it before) */
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if (blresult >= 0)
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{
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net_restorelock(count);
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}
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sched_unlock();
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leave_critical_section(flags);
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: net_lock
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*
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* Description:
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* Take the network lock
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*
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* Input Parameters:
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* None
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* failured (probably -ECANCELED).
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*
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****************************************************************************/
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int net_lock(void)
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{
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return nxrmutex_lock(&g_netlock);
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}
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/****************************************************************************
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* Name: net_trylock
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*
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* Description:
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* Try to take the network lock only when it is currently not locked.
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* Otherwise, it locks the semaphore. In either
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* case, the call returns without blocking.
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*
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* Input Parameters:
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* None
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* failured (probably -EAGAIN).
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*
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****************************************************************************/
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int net_trylock(void)
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{
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return nxrmutex_trylock(&g_netlock);
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}
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/****************************************************************************
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* Name: net_unlock
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*
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* Description:
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* Release the network lock.
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*
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* Input Parameters:
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* None
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void net_unlock(void)
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{
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nxrmutex_unlock(&g_netlock);
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}
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/****************************************************************************
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* Name: net_breaklock
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*
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* Description:
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* Break the lock, return information needed to restore re-entrant lock
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* state.
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*
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****************************************************************************/
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int net_breaklock(FAR unsigned int *count)
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{
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DEBUGASSERT(count != NULL);
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return nxrmutex_breaklock(&g_netlock, count);
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}
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/****************************************************************************
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* Name: net_restorelock
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*
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* Description:
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* Restore the locked state
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* failured (probably -ECANCELED).
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*
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****************************************************************************/
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int net_restorelock(unsigned int count)
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{
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return nxrmutex_restorelock(&g_netlock, count);
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}
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/****************************************************************************
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* Name: net_sem_timedwait
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*
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* Description:
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* Atomically wait for sem (or a timeout) while temporarily releasing
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* the lock on the network.
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*
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* Caution should be utilized. Because the network lock is relinquished
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* during the wait, there could be changes in the network state that occur
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* before the lock is recovered. Your design should account for this
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* possibility.
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*
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* Input Parameters:
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* sem - A reference to the semaphore to be taken.
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* timeout - The relative time to wait until a timeout is declared.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* any failure.
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*
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****************************************************************************/
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int net_sem_timedwait(sem_t *sem, unsigned int timeout)
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{
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return _net_timedwait(sem, true, timeout);
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}
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/****************************************************************************
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* Name: net_mutex_timedlock
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*
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* Description:
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* Atomically wait for mutex (or a timeout) while temporarily releasing
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* the lock on the network.
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*
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* Caution should be utilized. Because the network lock is relinquished
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* during the wait, there could be changes in the network state that occur
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* before the lock is recovered. Your design should account for this
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* possibility.
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*
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* Input Parameters:
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* mutex - A reference to the mutex to be taken.
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* timeout - The relative time to wait until a timeout is declared.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* any failure.
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*
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****************************************************************************/
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int net_mutex_timedlock(mutex_t *mutex, unsigned int timeout)
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{
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unsigned int count;
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irqstate_t flags;
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int blresult;
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int ret;
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flags = enter_critical_section(); /* No interrupts */
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sched_lock(); /* No context switches */
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/* Release the network lock, remembering my count. net_breaklock will
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* return a negated value if the caller does not hold the network lock.
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*/
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blresult = net_breaklock(&count);
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/* Now take the mutex, waiting if so requested. */
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if (timeout != UINT_MAX)
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{
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ret = nxmutex_timedlock(mutex, timeout);
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}
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else
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{
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/* Wait as long as necessary to get the lock */
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ret = nxmutex_lock(mutex);
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}
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/* Recover the network lock at the proper count (if we held it before) */
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if (blresult >= 0)
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{
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net_restorelock(count);
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}
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sched_unlock();
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leave_critical_section(flags);
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return ret;
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}
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/****************************************************************************
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* Name: net_sem_wait
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*
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* Description:
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* Atomically wait for sem while temporarily releasing the network lock.
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*
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* Caution should be utilized. Because the network lock is relinquished
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* during the wait, there could be changes in the network state that occur
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* before the lock is recovered. Your design should account for this
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* possibility.
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*
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* Input Parameters:
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* sem - A reference to the semaphore to be taken.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* any failure.
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*
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****************************************************************************/
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int net_sem_wait(sem_t *sem)
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{
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return net_sem_timedwait(sem, UINT_MAX);
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}
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/****************************************************************************
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* Name: net_mutex_lock
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*
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* Description:
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* Atomically wait for mutex while temporarily releasing the network lock.
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*
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* Caution should be utilized. Because the network lock is relinquished
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* during the wait, there could be changes in the network state that occur
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* before the lock is recovered. Your design should account for this
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* possibility.
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*
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* Input Parameters:
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* mutex - A reference to the mutex to be taken.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* any failure.
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*
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****************************************************************************/
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int net_mutex_lock(mutex_t *mutex)
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{
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return net_mutex_timedlock(mutex, UINT_MAX);
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}
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/****************************************************************************
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* Name: net_sem_timedwait_uninterruptible
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*
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* Description:
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* This function is wrapped version of net_sem_timedwait(), which is
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* uninterruptible and convenient for use.
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*
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* Input Parameters:
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* sem - A reference to the semaphore to be taken.
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* timeout - The relative time to wait until a timeout is declared.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* any failure.
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*
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****************************************************************************/
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int net_sem_timedwait_uninterruptible(sem_t *sem, unsigned int timeout)
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{
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return _net_timedwait(sem, false, timeout);
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}
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/****************************************************************************
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* Name: net_sem_wait_uninterruptible
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*
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* Description:
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* This function is wrapped version of net_sem_wait(), which is
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* uninterruptible and convenient for use.
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*
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* Input Parameters:
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* sem - A reference to the semaphore to be taken.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned on
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* any failure.
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*
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****************************************************************************/
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int net_sem_wait_uninterruptible(sem_t *sem)
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{
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return net_sem_timedwait_uninterruptible(sem, UINT_MAX);
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}
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#ifdef CONFIG_MM_IOB
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/****************************************************************************
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* Name: net_timedalloc
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*
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* Description:
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* Allocate an IOB. If no IOBs are available, then atomically wait for
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* for the IOB while temporarily releasing the lock on the network.
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* This function is wrapped version of nxsem_tickwait(), this wait will
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* be terminated when the specified timeout expires.
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*
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* Caution should be utilized. Because the network lock is relinquished
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* during the wait, there could be changes in the network state that occur
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* before the lock is recovered. Your design should account for this
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* possibility.
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*
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* Input Parameters:
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* throttled - An indication of the IOB allocation is "throttled"
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* timeout - The relative time to wait until a timeout is declared.
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*
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* Returned Value:
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* A pointer to the newly allocated IOB is returned on success. NULL is
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* returned on any allocation failure.
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*
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****************************************************************************/
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FAR struct iob_s *net_iobtimedalloc(bool throttled, unsigned int timeout)
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{
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FAR struct iob_s *iob;
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iob = iob_tryalloc(throttled);
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if (iob == NULL && timeout != 0)
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{
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unsigned int count;
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int blresult;
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/* There are no buffers available now. We will have to wait for one to
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* become available. But let's not do that with the network locked.
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*/
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blresult = net_breaklock(&count);
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iob = iob_timedalloc(throttled, timeout);
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if (blresult >= 0)
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{
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net_restorelock(count);
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}
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}
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return iob;
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}
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/****************************************************************************
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* Name: net_ioballoc
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*
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* Description:
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* Allocate an IOB. If no IOBs are available, then atomically wait for
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* for the IOB while temporarily releasing the lock on the network.
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*
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* Caution should be utilized. Because the network lock is relinquished
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* during the wait, there could be changes in the network state that occur
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* before the lock is recovered. Your design should account for this
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* possibility.
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*
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* Input Parameters:
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* throttled - An indication of the IOB allocation is "throttled"
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*
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* Returned Value:
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* A pointer to the newly allocated IOB is returned on success. NULL is
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* returned on any allocation failure.
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*
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****************************************************************************/
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FAR struct iob_s *net_ioballoc(bool throttled)
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{
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return net_iobtimedalloc(throttled, UINT_MAX);
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}
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#endif
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