144 lines
4.9 KiB
C
144 lines
4.9 KiB
C
/****************************************************************************
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* net/iob/iob_free.c
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*
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* Copyright (C) 2014 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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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#if defined(CONFIG_DEBUG) && defined(CONFIG_IOB_DEBUG)
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/* Force debug output (from this file only) */
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# undef CONFIG_DEBUG_NET
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# define CONFIG_DEBUG_NET 1
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#endif
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#include <semaphore.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/net/iob.h>
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#include "iob.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Public Data
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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: iob_free
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*
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* Description:
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* Free the I/O buffer at the head of a buffer chain returning it to the
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* free list. The link to the next I/O buffer in the chain is return.
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*
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****************************************************************************/
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FAR struct iob_s *iob_free(FAR struct iob_s *iob)
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{
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FAR struct iob_s *next = iob->io_flink;
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irqstate_t flags;
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nllvdbg("iob=%p io_pktlen=%u io_len=%u next=%p\n",
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iob, iob->io_pktlen, iob->io_len, next);
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/* Copy the data that only exists in the head of a I/O buffer chain into
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* the next entry.
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*/
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if (next)
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{
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/* Copy and decrement the total packet length, being careful to
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* do nothing too crazy.
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*/
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if (iob->io_pktlen > iob->io_len)
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{
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/* Adjust packet length and move it to the next entry */
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next->io_pktlen = iob->io_pktlen - iob->io_len;
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DEBUGASSERT(next->io_pktlen >= next->io_len);
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}
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else
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{
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/* This can only happen if the next entry is last entry in the
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* chain... and if it is empty
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*/
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next->io_pktlen = 0;
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DEBUGASSERT(next->io_len == 0 && next->io_flink == NULL);
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}
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nllvdbg("next=%p io_pktlen=%u io_len=%u\n",
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next, next->io_pktlen, next->io_len);
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}
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/* Free the I/O buffer by adding it to the head of the free list. We don't
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* know what context we are called from so we use extreme measures to
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* protect the free list: We disable interrupts very briefly.
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*/
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flags = irqsave();
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iob->io_flink = g_iob_freelist;
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g_iob_freelist = iob;
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/* Signal that an IOB is available */
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sem_post(&g_iob_sem);
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irqrestore(flags);
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/* And return the I/O buffer after the one that was freed */
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return next;
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}
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