761ee81956
currently, nuttx implements readv/writev on the top of read/write. while it might work for the simplest cases, it's broken by design. for example, it's impossible to make it work correctly for files which need to preserve data boundaries without allocating a single contiguous buffer. (udp socket, some character devices, etc) this change is a start of the migration to a better design. that is, implement read/write on the top of readv/writev. to avoid a single huge change, following things will NOT be done in this commit: * fix actual bugs caused by the original readv-based-on-read design. (cf. https://github.com/apache/nuttx/pull/12674) * adapt filesystems/drivers to actually benefit from the new interface. (except a few trivial examples) * eventually retire the old interface. * retire read/write syscalls. implement them in libc instead. * pread/pwrite/preadv/pwritev (except the introduction of struct uio, which is a preparation to back these variations with the new interface.)
527 lines
13 KiB
C
527 lines
13 KiB
C
/****************************************************************************
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* drivers/bch/bchdev_driver.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 <sys/types.h>
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#include <sys/stat.h>
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#include <sys/ioctl.h>
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#include <unistd.h>
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#include <string.h>
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#include <fcntl.h>
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#include <sched.h>
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#include <errno.h>
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#include <poll.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/fs/ioctl.h>
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#include <nuttx/drivers/drivers.h>
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#include "bch.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 Function Prototypes
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****************************************************************************/
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static int bch_open(FAR struct file *filep);
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static int bch_close(FAR struct file *filep);
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static off_t bch_seek(FAR struct file *filep, off_t offset, int whence);
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static ssize_t bch_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t bch_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen);
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static int bch_ioctl(FAR struct file *filep, int cmd,
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unsigned long arg);
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static int bch_poll(FAR struct file *filep, FAR struct pollfd *fds,
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bool setup);
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int bch_unlink(FAR struct inode *inode);
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#endif
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/****************************************************************************
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* Public Data
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****************************************************************************/
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const struct file_operations g_bch_fops =
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{
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bch_open, /* open */
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bch_close, /* close */
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bch_read, /* read */
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bch_write, /* write */
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bch_seek, /* seek */
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bch_ioctl, /* ioctl */
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NULL, /* mmap */
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NULL, /* truncate */
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bch_poll, /* poll */
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NULL, /* readv */
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NULL /* writev */
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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, bch_unlink /* unlink */
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#endif
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: bch_poll
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****************************************************************************/
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static int bch_poll(FAR struct file *filep, FAR struct pollfd *fds,
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bool setup)
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{
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if (setup)
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{
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poll_notify(&fds, 1, POLLIN | POLLOUT);
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}
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return OK;
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}
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/****************************************************************************
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* Name: bch_open
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*
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* Description: Open the block device
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*
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****************************************************************************/
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static int bch_open(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct bchlib_s *bch;
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int ret = OK;
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DEBUGASSERT(inode->i_private);
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bch = inode->i_private;
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/* Increment the reference count */
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ret = nxmutex_lock(&bch->lock);
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if (ret < 0)
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{
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return ret;
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}
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if (bch->refs == MAX_OPENCNT)
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{
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ret = -EMFILE;
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}
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else
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{
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bch->refs++;
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}
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nxmutex_unlock(&bch->lock);
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return ret;
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}
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/****************************************************************************
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* Name: bch_close
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*
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* Description: close the block device
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*
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****************************************************************************/
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static int bch_close(FAR struct file *filep)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct bchlib_s *bch;
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int ret = OK;
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DEBUGASSERT(inode->i_private);
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bch = inode->i_private;
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/* Get exclusive access */
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ret = nxmutex_lock(&bch->lock);
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if (ret < 0)
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{
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return ret;
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}
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/* Flush any dirty pages remaining in the cache */
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bchlib_flushsector(bch, false);
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/* Decrement the reference count (I don't use bchlib_decref() because I
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* want the entire close operation to be atomic wrt other driver
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* operations.
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*/
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if (bch->refs == 0)
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{
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ret = -EIO;
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}
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else
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{
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bch->refs--;
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/* If the reference count decremented to zero AND if the character
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* driver has been unlinked, then teardown the BCH device now.
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*/
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if (bch->refs == 0 && bch->unlinked)
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{
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/* Tear the driver down now. */
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ret = bchlib_teardown((FAR void *)bch);
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/* bchlib_teardown() would only fail if there are outstanding
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* references on the device. Since we know that is not true, it
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* should not fail at all.
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*/
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DEBUGASSERT(ret >= 0);
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if (ret >= 0)
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{
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/* Return without releasing the stale semaphore */
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return OK;
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}
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}
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}
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nxmutex_unlock(&bch->lock);
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return ret;
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}
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/****************************************************************************
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* Name: bch_seek
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****************************************************************************/
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static off_t bch_seek(FAR struct file *filep, off_t offset, int whence)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct bchlib_s *bch;
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off_t newpos;
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off_t ret;
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DEBUGASSERT(inode->i_private);
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bch = inode->i_private;
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ret = nxmutex_lock(&bch->lock);
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if (ret < 0)
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{
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return ret;
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}
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/* Determine the new, requested file position */
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switch (whence)
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{
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case SEEK_CUR:
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newpos = filep->f_pos + offset;
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break;
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case SEEK_SET:
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newpos = offset;
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break;
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case SEEK_END:
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newpos = (off_t)bch->sectsize * bch->nsectors + offset;
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break;
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default:
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/* Return EINVAL if the whence argument is invalid */
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nxmutex_unlock(&bch->lock);
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return -EINVAL;
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}
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/* Opengroup.org:
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*
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* "The lseek() function shall allow the file offset to be set beyond the
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* end of the existing data in the file. If data is later written at this
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* point, subsequent reads of data in the gap shall return bytes with the
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* value 0 until data is actually written into the gap."
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*
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* We can conform to the first part, but not the second. But return -EINVAL
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* if:
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*
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* "...the resulting file offset would be negative for a regular file,
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* block special file, or directory."
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*/
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if (newpos >= 0)
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{
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filep->f_pos = newpos;
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ret = newpos;
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}
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else
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{
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ret = -EINVAL;
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}
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nxmutex_unlock(&bch->lock);
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return ret;
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}
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/****************************************************************************
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* Name: bch_read
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****************************************************************************/
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static ssize_t bch_read(FAR struct file *filep, FAR char *buffer, size_t len)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct bchlib_s *bch;
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ssize_t ret;
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DEBUGASSERT(inode->i_private);
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bch = inode->i_private;
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ret = nxmutex_lock(&bch->lock);
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if (ret < 0)
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{
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return ret;
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}
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ret = bchlib_read(bch, buffer, filep->f_pos, len);
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if (ret > 0)
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{
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filep->f_pos += ret;
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}
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nxmutex_unlock(&bch->lock);
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return ret;
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}
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/****************************************************************************
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* Name: bch_write
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****************************************************************************/
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static ssize_t bch_write(FAR struct file *filep, FAR const char *buffer,
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size_t len)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct bchlib_s *bch;
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ssize_t ret = -EACCES;
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DEBUGASSERT(inode->i_private);
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bch = inode->i_private;
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if (!bch->readonly)
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{
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ret = nxmutex_lock(&bch->lock);
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if (ret < 0)
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{
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return ret;
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}
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ret = bchlib_write(bch, buffer, filep->f_pos, len);
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if (ret > 0)
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{
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filep->f_pos += ret;
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}
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nxmutex_unlock(&bch->lock);
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}
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return ret;
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}
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/****************************************************************************
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* Name: bch_ioctl
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*
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* Description:
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* Handle IOCTL commands
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*
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****************************************************************************/
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static int bch_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct bchlib_s *bch;
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int ret = -ENOTTY;
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DEBUGASSERT(inode->i_private);
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bch = inode->i_private;
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/* Process the call according to the command */
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switch (cmd)
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{
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/* This isa request to get the private data structure */
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case DIOC_GETPRIV:
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{
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FAR struct bchlib_s **bchr =
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(FAR struct bchlib_s **)((uintptr_t)arg);
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ret = nxmutex_lock(&bch->lock);
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if (ret < 0)
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{
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return ret;
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}
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if (!bchr || bch->refs == MAX_OPENCNT)
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{
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ret = -EINVAL;
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}
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else
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{
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bch->refs++;
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*bchr = bch;
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ret = OK;
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}
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nxmutex_unlock(&bch->lock);
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}
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break;
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/* This is a required to return the geometry of the underlying block
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* driver.
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*/
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case BIOC_GEOMETRY:
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{
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FAR struct geometry *geo = (FAR struct geometry *)((uintptr_t)arg);
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DEBUGASSERT(geo != NULL && bch->inode && bch->inode->u.i_bops &&
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bch->inode->u.i_bops->geometry);
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ret = bch->inode->u.i_bops->geometry(bch->inode, geo);
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if (ret < 0)
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{
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ferr("ERROR: geometry failed: %d\n", -ret);
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}
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else if (!geo->geo_available)
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{
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ferr("ERROR: geometry failed: %d\n", -ret);
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ret = -ENODEV;
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}
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}
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break;
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#ifdef CONFIG_BCH_ENCRYPTION
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/* This is a request to set the encryption key? */
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case DIOC_SETKEY:
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{
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memcpy(bch->key, (FAR void *)arg, CONFIG_BCH_ENCRYPTION_KEY_SIZE);
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ret = OK;
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}
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break;
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#endif
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case BIOC_FLUSH:
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{
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/* Flush any dirty pages remaining in the cache */
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ret = bchlib_flushsector(bch, false);
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if (ret < 0)
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{
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break;
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}
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/* Go through */
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}
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/* Pass the IOCTL command on to the contained block driver. */
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default:
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{
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FAR struct inode *bchinode = bch->inode;
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/* Does the block driver support the ioctl method? */
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if (bchinode->u.i_bops->ioctl != NULL)
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{
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ret = bchinode->u.i_bops->ioctl(bchinode, cmd, arg);
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}
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}
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break;
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}
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return ret;
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}
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/****************************************************************************
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* Name: bch_unlink
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*
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* Handle unlinking of the BCH device
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*
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****************************************************************************/
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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static int bch_unlink(FAR struct inode *inode)
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{
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FAR struct bchlib_s *bch;
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int ret = OK;
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DEBUGASSERT(inode->i_private);
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bch = inode->i_private;
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/* Get exclusive access to the BCH device */
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ret = nxmutex_lock(&bch->lock);
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if (ret < 0)
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{
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return ret;
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}
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/* Indicate that the driver has been unlinked */
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bch->unlinked = true;
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/* If there are no open references to the driver then teardown the BCH
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* device now.
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*/
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if (bch->refs == 0)
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{
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/* Tear the driver down now. */
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ret = bchlib_teardown((FAR void *)bch);
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/* bchlib_teardown() would only fail if there are outstanding
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* references on the device. Since we know that is not true, it
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* should not fail at all.
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*/
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DEBUGASSERT(ret >= 0);
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if (ret >= 0)
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{
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/* Return without releasing the stale semaphore */
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return OK;
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}
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}
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nxmutex_unlock(&bch->lock);
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return ret;
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}
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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