bdbuf.h File Reference

Block Device Buffer Management. More...

#include <rtems.h>
#include <rtems/libio.h>
#include <rtems/chain.h>
#include <rtems/blkdev.h>
#include <rtems/diskdevs.h>

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Data Structures
struct	rtems_bdbuf_buffer
	To manage buffers we using buffer descriptors (BD). More...
struct	rtems_bdbuf_buffer::rtems_bdbuf_avl_node
struct	rtems_bdbuf_group
	A group is a continuous block of buffer descriptors. More...
struct	rtems_bdbuf_config
	Buffering configuration definition. More...

Macros
#define	RTEMS_BDBUF_MAX_READ_AHEAD_BLOCKS_DEFAULT   0
	The default value for the maximum read-ahead blocks disables the read-ahead feature.
#define	RTEMS_BDBUF_MAX_WRITE_BLOCKS_DEFAULT   16
	Default maximum number of blocks to write at once.
#define	RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT   15
	Default swap-out task priority.
#define	RTEMS_BDBUF_SWAPOUT_TASK_SWAP_PERIOD_DEFAULT   250
	Default swap-out task swap period in milli seconds.
#define	RTEMS_BDBUF_SWAPOUT_TASK_BLOCK_HOLD_DEFAULT   1000
	Default swap-out task block hold time in milli seconds.
#define	RTEMS_BDBUF_SWAPOUT_WORKER_TASKS_DEFAULT   0
	Default swap-out worker tasks. More...
#define	RTEMS_BDBUF_SWAPOUT_WORKER_TASK_PRIORITY_DEFAULT   RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT
	Default swap-out worker task priority. More...
#define	RTEMS_BDBUF_READ_AHEAD_TASK_PRIORITY_DEFAULT   RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT
	Default read-ahead task priority. More...
#define	RTEMS_BDBUF_TASK_STACK_SIZE_DEFAULT   RTEMS_MINIMUM_STACK_SIZE
	Default task stack size for swap-out and worker tasks.
#define	RTEMS_BDBUF_CACHE_MEMORY_SIZE_DEFAULT   (64 * 512)
	Default size of memory allocated to the cache.
#define	RTEMS_BDBUF_BUFFER_MIN_SIZE_DEFAULT   (512)
	Default minimum size of buffers.
#define	RTEMS_BDBUF_BUFFER_MAX_SIZE_DEFAULT   (4096)
	Default maximum size of buffers.

Typedefs
typedef struct rtems_bdbuf_group	rtems_bdbuf_group
typedef struct rtems_bdbuf_buffer	rtems_bdbuf_buffer
	To manage buffers we using buffer descriptors (BD). More...
typedef struct rtems_bdbuf_config	rtems_bdbuf_config
	Buffering configuration definition. More...

Enumerations
enum	rtems_bdbuf_buf_state {   RTEMS_BDBUF_STATE_FREE = 0, RTEMS_BDBUF_STATE_EMPTY, RTEMS_BDBUF_STATE_CACHED, RTEMS_BDBUF_STATE_ACCESS_CACHED,   RTEMS_BDBUF_STATE_ACCESS_MODIFIED, RTEMS_BDBUF_STATE_ACCESS_EMPTY, RTEMS_BDBUF_STATE_ACCESS_PURGED, RTEMS_BDBUF_STATE_MODIFIED,   RTEMS_BDBUF_STATE_SYNC, RTEMS_BDBUF_STATE_TRANSFER, RTEMS_BDBUF_STATE_TRANSFER_PURGED }
	State of a buffer of the cache. More...

Functions
rtems_status_code	rtems_bdbuf_init (void)
	Prepare buffering layer to work - initialize buffer descritors and (if it is neccessary) buffers. More...
rtems_status_code	rtems_bdbuf_get (rtems_disk_device *dd, rtems_blkdev_bnum block, rtems_bdbuf_buffer **bd)
	Get block buffer for data to be written into. More...
rtems_status_code	rtems_bdbuf_read (rtems_disk_device *dd, rtems_blkdev_bnum block, rtems_bdbuf_buffer **bd)
	Get the block buffer and if not already in the cache read from the disk. More...
rtems_status_code	rtems_bdbuf_release (rtems_bdbuf_buffer *bd)
	Release the buffer obtained by a read call back to the cache. More...
rtems_status_code	rtems_bdbuf_release_modified (rtems_bdbuf_buffer *bd)
	Release the buffer allocated with a get or read call placing it on the modified list. More...
rtems_status_code	rtems_bdbuf_sync (rtems_bdbuf_buffer *bd)
	Release the buffer as modified and wait until it has been synchronized with the disk by writing it. More...
rtems_status_code	rtems_bdbuf_syncdev (rtems_disk_device *dd)
	Synchronize all modified buffers for this device with the disk and wait until the transfers have completed. More...
void	rtems_bdbuf_purge_dev (rtems_disk_device *dd)
	Purges all buffers corresponding to the disk device dd. More...
rtems_status_code	rtems_bdbuf_set_block_size (rtems_disk_device *dd, uint32_t block_size, bool sync)
	Sets the block size of a disk device. More...
void	rtems_bdbuf_get_device_stats (const rtems_disk_device *dd, rtems_blkdev_stats *stats)
	Returns the block device statistics.
void	rtems_bdbuf_reset_device_stats (rtems_disk_device *dd)
	Resets the block device statistics.

Variables
const rtems_bdbuf_config	rtems_bdbuf_configuration
	External reference to the configuration. More...

Detailed Description

Block Device Buffer Management.