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/*
* reqlist API
*
* Copyright (C) 2013 Proxmox Server Solutions
* Copyright (c) 2021 Virtuozzo International GmbH.
*
* Authors:
* Dietmar Maurer (dietmar@proxmox.com)
* Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef REQLIST_H
#define REQLIST_H
#include "qemu/coroutine.h"
/*
* The API is not thread-safe and shouldn't be. The struct is public to be part
* of other structures and protected by third-party locks, see
* block/block-copy.c for example.
*/
typedef struct BlockReq {
int64_t offset;
int64_t bytes;
CoQueue wait_queue; /* coroutines blocked on this req */
QLIST_ENTRY(BlockReq) list;
} BlockReq;
typedef QLIST_HEAD(, BlockReq) BlockReqList;
/*
* Initialize new request and add it to the list. Caller must be sure that
* there are no conflicting requests in the list.
*/
void reqlist_init_req(BlockReqList *reqs, BlockReq *req, int64_t offset,
int64_t bytes);
/* Search for request in the list intersecting with @offset/@bytes area. */
BlockReq *reqlist_find_conflict(BlockReqList *reqs, int64_t offset,
int64_t bytes);
/*
* If there are no intersecting requests return false. Otherwise, wait for the
* first found intersecting request to finish and return true.
*
* @lock is passed to qemu_co_queue_wait()
* False return value proves that lock was released at no point.
*/
bool coroutine_fn reqlist_wait_one(BlockReqList *reqs, int64_t offset,
int64_t bytes, CoMutex *lock);
/*
* Wait for all intersecting requests. It just calls reqlist_wait_one() in a
* loop, caller is responsible to stop producing new requests in this region
* in parallel, otherwise reqlist_wait_all() may never return.
*/
void coroutine_fn reqlist_wait_all(BlockReqList *reqs, int64_t offset,
int64_t bytes, CoMutex *lock);
/*
* Shrink request and wake all waiting coroutines (maybe some of them are not
* intersecting with shrunk request).
*/
void coroutine_fn reqlist_shrink_req(BlockReq *req, int64_t new_bytes);
/*
* Remove request and wake all waiting coroutines. Do not release any memory.
*/
void coroutine_fn reqlist_remove_req(BlockReq *req);
#endif /* REQLIST_H */
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