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/****************************************************************************
* drivers/bch/bchdev_unregister.c
*
* Copyright (C) 2008-2009, 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <fcntl.h>
#include <sched.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/ioctl.h>
#include "bch_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: bchdev_unregister
*
* Description:
* Unregister character driver access to a block device that was created
* by a previous call to bchdev_register().
*
****************************************************************************/
int bchdev_unregister(FAR const char *chardev)
{
FAR struct bchlib_s *bch;
int fd;
int ret;
/* Sanity check */
#ifdef CONFIG_DEBUG
if (!chardev)
{
return -EINVAL;
}
#endif
/* Open the character driver associated with chardev */
fd = open(chardev, O_RDONLY);
if (fd < 0)
{
dbg("Failed to open %s: %d\n", chardev, errno);
return -errno;
}
/* Get a reference to the internal data structure. On success, we
* will hold a reference count on the state structure.
*/
ret = ioctl(fd, DIOC_GETPRIV, (unsigned long)((uintptr_t)&bch));
(void)close(fd);
if (ret < 0)
{
dbg("ioctl failed: %d\n", errno);
return -errno;
}
/* Lock out context switches. If there are no other references
* and no context switches, then we can assume that we can safely
* teardown the driver.
*/
sched_lock();
/* Check if the internal structure is non-busy (we hold one reference). */
if (bch->refs > 1)
{
ret = -EBUSY;
goto errout_with_lock;
}
/* Unregister the driver (this cannot suspend or we lose our non-preemptive
* state!). Once the driver is successfully unregistered, we can assume
* we have exclusive access to the state instance.
*/
ret = unregister_driver(chardev);
if (ret < 0)
{
goto errout_with_lock;
}
sched_unlock();
/* Release the internal structure */
bch->refs = 0;
return bchlib_teardown(bch);
errout_with_lock:
bch->refs--;
sched_unlock();
return ret;
}
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