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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __BLK_SNAP_DIFF_IO_H
#define __BLK_SNAP_DIFF_IO_H
#include <linux/workqueue.h>
#include <linux/completion.h>
#ifdef STANDALONE_BDEVFILTER
#include "log_histogram.h"
#endif
struct diff_buffer;
/**
* struct diff_region - Describes the location of the chunks data on
* difference storage.
* @bdev:
* The target block device.
* @sector:
* The sector offset of the region's first sector.
* @count:
* The count of sectors in the region.
*/
struct diff_region {
struct block_device *bdev;
sector_t sector;
sector_t count;
};
/**
* struct diff_io_sync - Structure for notification about completion of
* synchronous I/O.
* @completion:
* Indicates that the request has been processed.
*
* Allows to wait for completion of the I/O operation in the
* current thread.
*/
struct diff_io_sync {
struct completion completion;
};
/**
* struct diff_io_async - Structure for notification about completion of
* asynchronous I/O.
* @work:
* The &struct work_struct allows to schedule execution of an I/O operation
* in a separate process.
* @notify_cb:
* A pointer to the callback function that will be executed when
* the I/O execution is completed.
* @ctx:
* The context for the callback function ¬ify_cb.
*
* Allows to schedule execution of an I/O operation.
*/
struct diff_io_async {
struct work_struct work;
void (*notify_cb)(void *ctx);
void *ctx;
};
/**
* struct diff_io - Structure for I/O maintenance.
* @error:
* Zero if the I/O operation is successful, or an error code if it fails.
* @bio_count:
* The count of bio in the I/O request.
* @is_write:
* Indicates that a write operation is being performed.
* @is_sync_io:
* Indicates that the operation is being performed synchronously.
* @notify:
* This union may contain the diff_io_sync or diff_io_async structure
* for synchronous or asynchronous request.
*
* The request to perform an I/O operation is executed for a region of sectors.
* Such a region may contain several bios. It is necessary to notify about the
* completion of processing of all bios. The diff_io structure allows to do it.
*/
struct diff_io {
int error;
atomic_t bio_count;
bool is_write;
bool is_sync_io;
union {
struct diff_io_sync sync;
struct diff_io_async async;
} notify;
};
int diff_io_init(void);
void diff_io_done(void);
static inline void diff_io_free(struct diff_io *diff_io)
{
kfree(diff_io);
if (diff_io)
memory_object_dec(memory_object_diff_io);
}
struct diff_io *diff_io_new_sync(bool is_write);
static inline struct diff_io *diff_io_new_sync_read(void)
{
return diff_io_new_sync(false);
};
static inline struct diff_io *diff_io_new_sync_write(void)
{
return diff_io_new_sync(true);
};
struct diff_io *diff_io_new_async(bool is_write, bool is_nowait,
void (*notify_cb)(void *ctx), void *ctx);
static inline struct diff_io *
diff_io_new_async_read(void (*notify_cb)(void *ctx), void *ctx, bool is_nowait)
{
return diff_io_new_async(false, is_nowait, notify_cb, ctx);
};
static inline struct diff_io *
diff_io_new_async_write(void (*notify_cb)(void *ctx), void *ctx, bool is_nowait)
{
return diff_io_new_async(true, is_nowait, notify_cb, ctx);
};
int diff_io_do(struct diff_io *diff_io, struct diff_region *diff_region,
#ifdef STANDALONE_BDEVFILTER
struct log_histogram *redirect_hg,
#endif
struct diff_buffer *diff_buffer, const bool is_nowait);
#ifdef STANDALONE_BDEVFILTER
void diff_io_endio(struct bio *bio);
#endif
#endif /* __BLK_SNAP_DIFF_IO_H */
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