bdbuf

  1# This file was automatically generated by SWIG (https://www.swig.org).
  2# Version 4.2.1
  3#
  4# Do not make changes to this file unless you know what you are doing - modify
  5# the SWIG interface file instead.
  6
  7from sys import version_info as _swig_python_version_info
  8from mock_rtems import _bdbuf as _bdbuf
  9
 10try:
 11    import builtins as __builtin__
 12except ImportError:
 13    import __builtin__
 14
 15def _swig_repr(self):
 16    try:
 17        strthis = "proxy of " + self.this.__repr__()
 18    except __builtin__.Exception:
 19        strthis = ""
 20    return "<%s.%s; %s >" % (self.__class__.__module__, self.__class__.__name__, strthis,)
 21
 22
 23def _swig_setattr_nondynamic_instance_variable(set):
 24    def set_instance_attr(self, name, value):
 25        if name == "this":
 26            set(self, name, value)
 27        elif name == "thisown":
 28            self.this.own(value)
 29        elif hasattr(self, name) and isinstance(getattr(type(self), name), property):
 30            set(self, name, value)
 31        else:
 32            raise AttributeError("You cannot add instance attributes to %s" % self)
 33    return set_instance_attr
 34
 35
 36def _swig_setattr_nondynamic_class_variable(set):
 37    def set_class_attr(cls, name, value):
 38        if hasattr(cls, name) and not isinstance(getattr(cls, name), property):
 39            set(cls, name, value)
 40        else:
 41            raise AttributeError("You cannot add class attributes to %s" % cls)
 42    return set_class_attr
 43
 44
 45def _swig_add_metaclass(metaclass):
 46    """Class decorator for adding a metaclass to a SWIG wrapped class - a slimmed down version of six.add_metaclass"""
 47    def wrapper(cls):
 48        return metaclass(cls.__name__, cls.__bases__, cls.__dict__.copy())
 49    return wrapper
 50
 51
 52class _SwigNonDynamicMeta(type):
 53    """Meta class to enforce nondynamic attributes (no new attributes) for a class"""
 54    __setattr__ = _swig_setattr_nondynamic_class_variable(type.__setattr__)
 55
 56
 57RTEMS_BDBUF_STATE_FREE = _bdbuf.RTEMS_BDBUF_STATE_FREE
 58r"""Free."""
 59RTEMS_BDBUF_STATE_EMPTY = _bdbuf.RTEMS_BDBUF_STATE_EMPTY
 60r"""Empty."""
 61RTEMS_BDBUF_STATE_CACHED = _bdbuf.RTEMS_BDBUF_STATE_CACHED
 62r"""Cached."""
 63RTEMS_BDBUF_STATE_ACCESS_CACHED = _bdbuf.RTEMS_BDBUF_STATE_ACCESS_CACHED
 64r"""Accessed by upper layer with cached data."""
 65RTEMS_BDBUF_STATE_ACCESS_MODIFIED = _bdbuf.RTEMS_BDBUF_STATE_ACCESS_MODIFIED
 66r"""Accessed by upper layer with modified data."""
 67RTEMS_BDBUF_STATE_ACCESS_EMPTY = _bdbuf.RTEMS_BDBUF_STATE_ACCESS_EMPTY
 68r"""Accessed by upper layer with invalid data."""
 69RTEMS_BDBUF_STATE_ACCESS_PURGED = _bdbuf.RTEMS_BDBUF_STATE_ACCESS_PURGED
 70r"""Accessed by upper layer with purged data."""
 71RTEMS_BDBUF_STATE_MODIFIED = _bdbuf.RTEMS_BDBUF_STATE_MODIFIED
 72r"""Modified by upper layer."""
 73RTEMS_BDBUF_STATE_SYNC = _bdbuf.RTEMS_BDBUF_STATE_SYNC
 74r"""Scheduled for synchronization."""
 75RTEMS_BDBUF_STATE_TRANSFER = _bdbuf.RTEMS_BDBUF_STATE_TRANSFER
 76r"""In transfer by block device driver."""
 77RTEMS_BDBUF_STATE_TRANSFER_PURGED = _bdbuf.RTEMS_BDBUF_STATE_TRANSFER_PURGED
 78r"""In transfer by block device driver and purged."""
 79class rtems_bdbuf_buffer(object):
 80    r"""
 81    To manage buffers we using buffer descriptors (BD). A BD holds a buffer plus
 82    a range of other information related to managing the buffer in the cache. To
 83    speed-up buffer lookup descriptors are organized in AVL-Tree. The fields
 84    'dd' and 'block' are search keys.
 85    """
 86
 87    thisown = property(lambda x: x.this.own(), lambda x, v: x.this.own(v), doc="The membership flag")
 88    __repr__ = _swig_repr
 89    avl = property(_bdbuf.rtems_bdbuf_buffer_avl_get, _bdbuf.rtems_bdbuf_buffer_avl_set, doc=r"""avl : struct rtems_bdbuf_avl_node""")
 90    link = property(_bdbuf.rtems_bdbuf_buffer_link_get, _bdbuf.rtems_bdbuf_buffer_link_set, doc=r""" Link the BD onto a number of lists.""")
 91    dd = property(_bdbuf.rtems_bdbuf_buffer_dd_get, _bdbuf.rtems_bdbuf_buffer_dd_set, doc=r""" disk device""")
 92    block = property(_bdbuf.rtems_bdbuf_buffer_block_get, _bdbuf.rtems_bdbuf_buffer_block_set, doc=r""" block number on the device""")
 93    buffer = property(_bdbuf.rtems_bdbuf_buffer_buffer_get, _bdbuf.rtems_bdbuf_buffer_buffer_set, doc=r""" Pointer to the buffer memory area""")
 94    state = property(_bdbuf.rtems_bdbuf_buffer_state_get, _bdbuf.rtems_bdbuf_buffer_state_set, doc=r""" State of the buffer.""")
 95    waiters = property(_bdbuf.rtems_bdbuf_buffer_waiters_get, _bdbuf.rtems_bdbuf_buffer_waiters_set, doc=r"""
 96     The number of threads waiting on this
 97    buffer.
 98    """)
 99    group = property(_bdbuf.rtems_bdbuf_buffer_group_get, _bdbuf.rtems_bdbuf_buffer_group_set, doc=r"""
100     Pointer to the group of BDs this BD is
101    part of.
102    """)
103    hold_timer = property(_bdbuf.rtems_bdbuf_buffer_hold_timer_get, _bdbuf.rtems_bdbuf_buffer_hold_timer_set, doc=r"""
104     Timer to indicate how long a buffer
105    has been held in the cache modified.
106    """)
107    references = property(_bdbuf.rtems_bdbuf_buffer_references_get, _bdbuf.rtems_bdbuf_buffer_references_set, doc=r""" Allow reference counting by owner.""")
108    user = property(_bdbuf.rtems_bdbuf_buffer_user_get, _bdbuf.rtems_bdbuf_buffer_user_set, doc=r""" User data.""")
109
110    def __init__(self):
111        r"""__init__(rtems_bdbuf_buffer self) -> rtems_bdbuf_buffer"""
112        _bdbuf.rtems_bdbuf_buffer_swiginit(self, _bdbuf.new_rtems_bdbuf_buffer())
113    __swig_destroy__ = _bdbuf.delete_rtems_bdbuf_buffer
114
115# Register rtems_bdbuf_buffer in _bdbuf:
116_bdbuf.rtems_bdbuf_buffer_swigregister(rtems_bdbuf_buffer)
117class rtems_bdbuf_avl_node(object):
118    r"""Proxy of C rtems_bdbuf_avl_node struct."""
119
120    thisown = property(lambda x: x.this.own(), lambda x, v: x.this.own(v), doc="The membership flag")
121    __repr__ = _swig_repr
122    left = property(_bdbuf.rtems_bdbuf_avl_node_left_get, _bdbuf.rtems_bdbuf_avl_node_left_set, doc=r""" Left Child""")
123    right = property(_bdbuf.rtems_bdbuf_avl_node_right_get, _bdbuf.rtems_bdbuf_avl_node_right_set, doc=r""" Right Child""")
124    cache = property(_bdbuf.rtems_bdbuf_avl_node_cache_get, _bdbuf.rtems_bdbuf_avl_node_cache_set, doc=r""" Cache""")
125    bal = property(_bdbuf.rtems_bdbuf_avl_node_bal_get, _bdbuf.rtems_bdbuf_avl_node_bal_set, doc=r""" The balance of the sub-tree""")
126
127    def __init__(self):
128        r"""__init__(rtems_bdbuf_avl_node self) -> rtems_bdbuf_avl_node"""
129        _bdbuf.rtems_bdbuf_avl_node_swiginit(self, _bdbuf.new_rtems_bdbuf_avl_node())
130    __swig_destroy__ = _bdbuf.delete_rtems_bdbuf_avl_node
131
132# Register rtems_bdbuf_avl_node in _bdbuf:
133_bdbuf.rtems_bdbuf_avl_node_swigregister(rtems_bdbuf_avl_node)
134class rtems_bdbuf_group(object):
135    r"""
136    A group is a continuous block of buffer descriptors. A group covers the
137    maximum configured buffer size and is the allocation size for the buffers to
138    a specific buffer size. If you allocate a buffer to be a specific size, all
139    buffers in the group, if there are more than 1 will also be that size. The
140    number of buffers in a group is a multiple of 2, ie 1, 2, 4, 8, etc.
141    """
142
143    thisown = property(lambda x: x.this.own(), lambda x, v: x.this.own(v), doc="The membership flag")
144    __repr__ = _swig_repr
145    link = property(_bdbuf.rtems_bdbuf_group_link_get, _bdbuf.rtems_bdbuf_group_link_set, doc=r"""
146     Link the groups on a LRU list if they
147    have no buffers in use.
148    """)
149    bds_per_group = property(_bdbuf.rtems_bdbuf_group_bds_per_group_get, _bdbuf.rtems_bdbuf_group_bds_per_group_set, doc=r"""
150     The number of BD allocated to this
151    group. This value must be a multiple of
152    2.
153    """)
154    users = property(_bdbuf.rtems_bdbuf_group_users_get, _bdbuf.rtems_bdbuf_group_users_set, doc=r""" How many users the block has.""")
155    bdbuf = property(_bdbuf.rtems_bdbuf_group_bdbuf_get, _bdbuf.rtems_bdbuf_group_bdbuf_set, doc=r""" First BD this block covers.""")
156
157    def __init__(self):
158        r"""__init__(rtems_bdbuf_group self) -> rtems_bdbuf_group"""
159        _bdbuf.rtems_bdbuf_group_swiginit(self, _bdbuf.new_rtems_bdbuf_group())
160    __swig_destroy__ = _bdbuf.delete_rtems_bdbuf_group
161
162# Register rtems_bdbuf_group in _bdbuf:
163_bdbuf.rtems_bdbuf_group_swigregister(rtems_bdbuf_group)
164class rtems_bdbuf_config(object):
165    r"""
166    Buffering configuration definition. See confdefs.h for support on using this
167    structure.
168    """
169
170    thisown = property(lambda x: x.this.own(), lambda x, v: x.this.own(v), doc="The membership flag")
171    __repr__ = _swig_repr
172    max_read_ahead_blocks = property(_bdbuf.rtems_bdbuf_config_max_read_ahead_blocks_get, _bdbuf.rtems_bdbuf_config_max_read_ahead_blocks_set, doc=r"""
173     Number of blocks to read
174    ahead.
175    """)
176    max_write_blocks = property(_bdbuf.rtems_bdbuf_config_max_write_blocks_get, _bdbuf.rtems_bdbuf_config_max_write_blocks_set, doc=r"""
177     Number of blocks to write
178    at once.
179    """)
180    swapout_priority = property(_bdbuf.rtems_bdbuf_config_swapout_priority_get, _bdbuf.rtems_bdbuf_config_swapout_priority_set, doc=r"""
181     Priority of the swap out
182    task.
183    """)
184    swapout_period = property(_bdbuf.rtems_bdbuf_config_swapout_period_get, _bdbuf.rtems_bdbuf_config_swapout_period_set, doc=r"""
185     Period swap-out checks buf
186    timers.
187    """)
188    swap_block_hold = property(_bdbuf.rtems_bdbuf_config_swap_block_hold_get, _bdbuf.rtems_bdbuf_config_swap_block_hold_set, doc=r""" Period a buffer is held.""")
189    swapout_workers = property(_bdbuf.rtems_bdbuf_config_swapout_workers_get, _bdbuf.rtems_bdbuf_config_swapout_workers_set, doc=r"""
190     The number of worker
191    threads for the swap-out
192    task.
193    """)
194    swapout_worker_priority = property(_bdbuf.rtems_bdbuf_config_swapout_worker_priority_get, _bdbuf.rtems_bdbuf_config_swapout_worker_priority_set, doc=r"""
195     Priority of the swap out
196    task.
197    """)
198    task_stack_size = property(_bdbuf.rtems_bdbuf_config_task_stack_size_get, _bdbuf.rtems_bdbuf_config_task_stack_size_set, doc=r"""
199     Task stack size for swap-out
200    task and worker threads.
201    """)
202    size = property(_bdbuf.rtems_bdbuf_config_size_get, _bdbuf.rtems_bdbuf_config_size_set, doc=r"""
203     Size of memory in the
204    cache
205    """)
206    buffer_min = property(_bdbuf.rtems_bdbuf_config_buffer_min_get, _bdbuf.rtems_bdbuf_config_buffer_min_set, doc=r""" Minimum buffer size.""")
207    buffer_max = property(_bdbuf.rtems_bdbuf_config_buffer_max_get, _bdbuf.rtems_bdbuf_config_buffer_max_set, doc=r"""
208     Maximum buffer size
209    supported. It is also the
210    allocation size.
211    """)
212    read_ahead_priority = property(_bdbuf.rtems_bdbuf_config_read_ahead_priority_get, _bdbuf.rtems_bdbuf_config_read_ahead_priority_set, doc=r"""
213     Priority of the read-ahead
214    task.
215    """)
216
217    def __init__(self):
218        r"""__init__(rtems_bdbuf_config self) -> rtems_bdbuf_config"""
219        _bdbuf.rtems_bdbuf_config_swiginit(self, _bdbuf.new_rtems_bdbuf_config())
220    __swig_destroy__ = _bdbuf.delete_rtems_bdbuf_config
221
222# Register rtems_bdbuf_config in _bdbuf:
223_bdbuf.rtems_bdbuf_config_swigregister(rtems_bdbuf_config)
224RTEMS_BDBUF_MAX_READ_AHEAD_BLOCKS_DEFAULT = _bdbuf.RTEMS_BDBUF_MAX_READ_AHEAD_BLOCKS_DEFAULT
225r"""
226    The default value for the maximum read-ahead blocks disables the read-ahead
227    feature.
228    """
229RTEMS_BDBUF_MAX_WRITE_BLOCKS_DEFAULT = _bdbuf.RTEMS_BDBUF_MAX_WRITE_BLOCKS_DEFAULT
230r"""Default maximum number of blocks to write at once."""
231RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT = _bdbuf.RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT
232r"""Default swap-out task priority."""
233RTEMS_BDBUF_SWAPOUT_TASK_SWAP_PERIOD_DEFAULT = _bdbuf.RTEMS_BDBUF_SWAPOUT_TASK_SWAP_PERIOD_DEFAULT
234r"""Default swap-out task swap period in milli seconds."""
235RTEMS_BDBUF_SWAPOUT_TASK_BLOCK_HOLD_DEFAULT = _bdbuf.RTEMS_BDBUF_SWAPOUT_TASK_BLOCK_HOLD_DEFAULT
236r"""Default swap-out task block hold time in milli seconds."""
237RTEMS_BDBUF_SWAPOUT_WORKER_TASKS_DEFAULT = _bdbuf.RTEMS_BDBUF_SWAPOUT_WORKER_TASKS_DEFAULT
238r"""Default swap-out worker tasks. Currently disabled."""
239RTEMS_BDBUF_SWAPOUT_WORKER_TASK_PRIORITY_DEFAULT = _bdbuf.RTEMS_BDBUF_SWAPOUT_WORKER_TASK_PRIORITY_DEFAULT
240r"""Default swap-out worker task priority. The same as the swap-out task."""
241RTEMS_BDBUF_READ_AHEAD_TASK_PRIORITY_DEFAULT = _bdbuf.RTEMS_BDBUF_READ_AHEAD_TASK_PRIORITY_DEFAULT
242r"""Default read-ahead task priority.  The same as the swap-out task."""
243RTEMS_BDBUF_CACHE_MEMORY_SIZE_DEFAULT = _bdbuf.RTEMS_BDBUF_CACHE_MEMORY_SIZE_DEFAULT
244r"""
245    Default task stack size for swap-out and worker tasks.
246
247    Default size of memory allocated to the cache.
248    """
249RTEMS_BDBUF_BUFFER_MIN_SIZE_DEFAULT = _bdbuf.RTEMS_BDBUF_BUFFER_MIN_SIZE_DEFAULT
250r"""Default minimum size of buffers."""
251RTEMS_BDBUF_BUFFER_MAX_SIZE_DEFAULT = _bdbuf.RTEMS_BDBUF_BUFFER_MAX_SIZE_DEFAULT
252r"""Default maximum size of buffers."""
253
254def rtems_bdbuf_init():
255    r"""
256    Prepare buffering layer to work - initialize buffer descritors and (if it is
257    neccessary) buffers. After initialization all blocks is placed into the
258    ready state.
259    """
260    return _bdbuf.rtems_bdbuf_init()
261
262def rtems_bdbuf_get(dd, block, bd):
263    r"""
264    Get block buffer for data to be written into. The buffers is set to the
265    access or modified access state. If the buffer is in the cache and modified
266    the state is access modified else the state is access. This buffer contents
267    are not initialised if the buffer is not already in the cache. If the block
268    is already resident in memory it is returned how-ever if not in memory the
269    buffer is not read from disk. This call is used when writing the whole block
270    on a disk rather than just changing a part of it. If there is no buffers
271    available this call will block. A buffer obtained with this call will not be
272    involved in a transfer request and will not be returned to another user
273    until released. If the buffer is already with a user when this call is made
274    the call is blocked until the buffer is returned. The highest priority
275    waiter will obtain the buffer first.
276
277    The block number is the linear block number. This is relative to the start
278    of the partition on the media.
279
280    Before you can use this function, the rtems_bdbuf_init() routine must be
281    called at least once to initialize the cache, otherwise a fatal error will
282    occur.
283
284    :type dd: rtems_disk_device
285    :param dd: [in] The disk device.
286    :type block: rtems_blkdev_bnum
287    :param block: [in] Linear media block number.
288    :type bd: :py:class:`rtems_bdbuf_buffer`
289    :param bd: [out] Reference to the buffer descriptor pointer.
290    """
291    return _bdbuf.rtems_bdbuf_get(dd, block, bd)
292
293def rtems_bdbuf_read(dd, block, bd):
294    r"""
295    Get the block buffer and if not already in the cache read from the disk. If
296    specified block already cached return. The buffer is set to the access or
297    modified access state. If the buffer is in the cache and modified the state
298    is access modified else the state is access. If block is already being read
299    from disk for being written to disk this call blocks. If the buffer is
300    waiting to be written it is removed from modified queue and returned to the
301    user. If the buffer is not in the cache a new buffer is obtained and the
302    data read from disk. The call may block until these operations complete. A
303    buffer obtained with this call will not be involved in a transfer request
304    and will not be returned to another user until released. If the buffer is
305    already with a user when this call is made the call is blocked until the
306    buffer is returned. The highest priority waiter will obtain the buffer
307    first.
308
309    Before you can use this function, the rtems_bdbuf_init() routine must be
310    called at least once to initialize the cache, otherwise a fatal error will
311    occur.
312
313    :type dd: rtems_disk_device
314    :param dd: [in] The disk device.
315    :type block: rtems_blkdev_bnum
316    :param block: [in] Linear media block number.
317    :type bd: :py:class:`rtems_bdbuf_buffer`
318    :param bd: [out] Reference to the buffer descriptor pointer.
319    """
320    return _bdbuf.rtems_bdbuf_read(dd, block, bd)
321
322def rtems_bdbuf_peek(dd, block, nr_blocks):
323    r"""
324    Give a hint which blocks should be cached next.
325
326    Provide a hint to the read ahead mechanism which blocks should be cached
327    next. This overwrites the default linear pattern. You should use it in (for
328    example) a file system to tell bdbuf where the next part of a fragmented file
329    is. If you know the length of the file, you can provide that too.
330
331    Before you can use this function, the rtems_bdbuf_init() routine must be
332    called at least once to initialize everything. Otherwise you might get
333    unexpected results.
334
335    :type dd: rtems_disk_device
336    :param dd: [in] The disk device.
337    :type block: rtems_blkdev_bnum
338    :param block: [in] Linear media block number.
339    :type nr_blocks: uint32_t
340    :param nr_blocks: [in] Number of consecutive blocks that can be pre-fetched.
341    """
342    return _bdbuf.rtems_bdbuf_peek(dd, block, nr_blocks)
343
344def rtems_bdbuf_release(bd):
345    r"""
346    Release the buffer obtained by a read call back to the cache. If the buffer
347    was obtained by a get call and was not already in the cache the release
348    modified call should be used. A buffer released with this call obtained by a
349    get call may not be in sync with the contents on disk. If the buffer was in
350    the cache and modified before this call it will be returned to the modified
351    queue. The buffers is returned to the end of the LRU list.
352
353    Before you can use this function, the rtems_bdbuf_init() routine must be
354    called at least once to initialize the cache, otherwise a fatal error will
355    occur.
356
357    :type bd: :py:class:`rtems_bdbuf_buffer`
358    :param bd: [in] Reference to the buffer descriptor.  The buffer descriptor
359        reference must not be ``NULL`` and must be obtained via rtems_bdbuf_get() or
360        rtems_bdbuf_read().
361    """
362    return _bdbuf.rtems_bdbuf_release(bd)
363
364def rtems_bdbuf_release_modified(bd):
365    r"""
366    Release the buffer allocated with a get or read call placing it on the
367    modified list.  If the buffer was not released modified before the hold
368    timer is set to the configuration value. If the buffer had been released
369    modified before but not written to disk the hold timer is not updated. The
370    buffer will be written to disk when the hold timer has expired, there are
371    not more buffers available in the cache and a get or read buffer needs one
372    or a sync call has been made. If the buffer is obtained with a get or read
373    before the hold timer has expired the buffer will be returned to the user.
374
375    Before you can use this function, the rtems_bdbuf_init() routine must be
376    called at least once to initialize the cache, otherwise a fatal error will
377    occur.
378
379    :type bd: :py:class:`rtems_bdbuf_buffer`
380    :param bd: [in] Reference to the buffer descriptor.  The buffer descriptor
381        reference must not be ``NULL`` and must be obtained via rtems_bdbuf_get() or
382        rtems_bdbuf_read().
383    """
384    return _bdbuf.rtems_bdbuf_release_modified(bd)
385
386def rtems_bdbuf_sync(bd):
387    r"""
388    Release the buffer as modified and wait until it has been synchronized with
389    the disk by writing it. This buffer will be the first to be transfer to disk
390    and other buffers may also be written if the maximum number of blocks in a
391    requests allows it.
392
393    Notes: This code does not lock the sync mutex and stop additions to the
394          modified queue.
395
396    Before you can use this function, the rtems_bdbuf_init() routine must be
397    called at least once to initialize the cache, otherwise a fatal error will
398    occur.
399
400    :type bd: :py:class:`rtems_bdbuf_buffer`
401    :param bd: [in] Reference to the buffer descriptor.  The buffer descriptor
402        reference must not be ``NULL`` and must be obtained via rtems_bdbuf_get() or
403        rtems_bdbuf_read().
404    """
405    return _bdbuf.rtems_bdbuf_sync(bd)
406
407def rtems_bdbuf_syncdev(dd):
408    r"""
409    Synchronize all modified buffers for this device with the disk and wait
410    until the transfers have completed. The sync mutex for the cache is locked
411    stopping the addition of any further modified buffers. It is only the
412    currently modified buffers that are written.
413
414    Notes: Nesting calls to sync multiple devices will be handled sequentially. A
415    nested call will be blocked until the first sync request has complete.
416
417    Before you can use this function, the rtems_bdbuf_init() routine must be
418    called at least once to initialize the cache, otherwise a fatal error will
419    occur.
420
421    :type dd: rtems_disk_device
422    :param dd: [in] The disk device.
423    """
424    return _bdbuf.rtems_bdbuf_syncdev(dd)
425
426def rtems_bdbuf_purge_dev(dd):
427    r"""
428    Purges all buffers corresponding to the disk device *dd*.
429
430    This may result in loss of data.  The read-ahead state of this device is reset.
431
432    Before you can use this function, the rtems_bdbuf_init() routine must be
433    called at least once to initialize the cache, otherwise a fatal error will
434    occur.
435
436    :type dd: rtems_disk_device
437    :param dd: [in] The disk device.
438    """
439    return _bdbuf.rtems_bdbuf_purge_dev(dd)
440
441def rtems_bdbuf_set_block_size(dd, block_size, sync):
442    r"""
443    Sets the block size of a disk device.
444
445    This will set the block size derived fields of the disk device.  If
446    requested the disk device is synchronized before the block size change
447    occurs.  Since the cache is unlocked during the synchronization operation
448    some tasks may access the disk device in the meantime.  This may result in
449    loss of data.  After the synchronization the disk device is purged to ensure
450    a consistent cache state and the block size change occurs.  This also resets
451    the read-ahead state of this disk device.  Due to the purge operation this
452    may result in loss of data.
453
454    Before you can use this function, the rtems_bdbuf_init() routine must be
455    called at least once to initialize the cache, otherwise a fatal error will
456    occur.
457
458    :type dd: rtems_disk_device
459    :param dd: [in, out] The disk device.
460    :type block_size: uint32_t
461    :param block_size: [in] The new block size in bytes.
462    :type sync: boolean
463    :param sync: [in] If ``true``, then synchronize the disk device before the
464        block size change.
465    """
466    return _bdbuf.rtems_bdbuf_set_block_size(dd, block_size, sync)
467
468def rtems_bdbuf_get_device_stats(dd, stats):
469    r"""Returns the block device statistics."""
470    return _bdbuf.rtems_bdbuf_get_device_stats(dd, stats)
471
472def rtems_bdbuf_reset_device_stats(dd):
473    r"""Resets the block device statistics."""
474    return _bdbuf.rtems_bdbuf_reset_device_stats(dd)
475
476cvar = _bdbuf.cvar
477rtems_bdbuf_configuration = cvar.rtems_bdbuf_configuration