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