drivers/md/persistent-data/dm-block-manager.h

Source file repositories/reference/linux-study-clean/drivers/md/persistent-data/dm-block-manager.h

File Facts

System
Linux kernel
Corpus path
drivers/md/persistent-data/dm-block-manager.h
Extension
.h
Size
4269 bytes
Lines
139
Domain
Driver Families
Bucket
drivers/md
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct dm_block_validator {
	const char *name;
	void (*prepare_for_write)(const struct dm_block_validator *v,
				  struct dm_block *b, size_t block_size);

	/*
	 * Return 0 if the checksum is valid or < 0 on error.
	 */
	int (*check)(const struct dm_block_validator *v,
		     struct dm_block *b, size_t block_size);
};

/*----------------------------------------------------------------*/

/*
 * You can have multiple concurrent readers or a single writer holding a
 * block lock.
 */

/*
 * dm_bm_lock() locks a block and returns through @result a pointer to
 * memory that holds a copy of that block.  If you have write-locked the
 * block then any changes you make to memory pointed to by @result will be
 * written back to the disk sometime after dm_bm_unlock is called.
 */
int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b,
		    const struct dm_block_validator *v,
		    struct dm_block **result);

int dm_bm_write_lock(struct dm_block_manager *bm, dm_block_t b,
		     const struct dm_block_validator *v,
		     struct dm_block **result);

/*
 * The *_try_lock variants return -EWOULDBLOCK if the block isn't
 * available immediately.
 */
int dm_bm_read_try_lock(struct dm_block_manager *bm, dm_block_t b,
			const struct dm_block_validator *v,
			struct dm_block **result);

/*
 * Use dm_bm_write_lock_zero() when you know you're going to
 * overwrite the block completely.  It saves a disk read.
 */
int dm_bm_write_lock_zero(struct dm_block_manager *bm, dm_block_t b,
			  const struct dm_block_validator *v,
			  struct dm_block **result);

void dm_bm_unlock(struct dm_block *b);

/*
 * It's a common idiom to have a superblock that should be committed last.
 *
 * @superblock should be write-locked on entry. It will be unlocked during
 * this function.  All dirty blocks are guaranteed to be written and flushed
 * before the superblock.
 *
 * This method always blocks.
 */
int dm_bm_flush(struct dm_block_manager *bm);

/*
 * Request data is prefetched into the cache.
 */
void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b);

/*
 * Switches the bm to a read only mode.  Once read-only mode
 * has been entered the following functions will return -EPERM.
 *
 *   dm_bm_write_lock
 *   dm_bm_write_lock_zero
 *   dm_bm_flush_and_unlock
 *
 * Additionally you should not use dm_bm_unlock_move, however no error will
 * be returned if you do.
 */
bool dm_bm_is_read_only(struct dm_block_manager *bm);
void dm_bm_set_read_only(struct dm_block_manager *bm);
void dm_bm_set_read_write(struct dm_block_manager *bm);

u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor);

/*----------------------------------------------------------------*/

#endif	/* _LINUX_DM_BLOCK_MANAGER_H */

Annotation

Implementation Notes