| 1 | /* |
| 2 | * reqlist API |
| 3 | * |
| 4 | * Copyright (C) 2013 Proxmox Server Solutions |
| 5 | * Copyright (c) 2021 Virtuozzo International GmbH. |
| 6 | * |
| 7 | * Authors: |
| 8 | * Dietmar Maurer (dietmar@proxmox.com) |
| 9 | * Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> |
| 10 | * |
| 11 | * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 12 | * See the COPYING file in the top-level directory. |
| 13 | */ |
| 14 | |
| 15 | #include "qemu/osdep.h" |
| 16 | #include "qemu/range.h" |
| 17 | |
| 18 | #include "block/reqlist.h" |
| 19 | |
| 20 | void reqlist_init_req(BlockReqList *reqs, BlockReq *req, int64_t offset, |
| 21 | int64_t bytes) |
| 22 | { |
| 23 | *req = (BlockReq) { |
| 24 | .offset = offset, |
| 25 | .bytes = bytes, |
| 26 | }; |
| 27 | qemu_co_queue_init(&req->wait_queue); |
| 28 | QLIST_INSERT_HEAD(reqs, req, list); |
| 29 | } |
| 30 | |
| 31 | BlockReq *reqlist_find_conflict(BlockReqList *reqs, int64_t offset, |
| 32 | int64_t bytes) |
| 33 | { |
| 34 | BlockReq *r; |
| 35 | |
| 36 | QLIST_FOREACH(r, reqs, list) { |
| 37 | if (ranges_overlap(offset, bytes, r->offset, r->bytes)) { |
| 38 | return r; |
| 39 | } |
| 40 | } |
| 41 | |
| 42 | return NULL; |
| 43 | } |
| 44 | |
| 45 | bool coroutine_fn reqlist_wait_one(BlockReqList *reqs, int64_t offset, |
| 46 | int64_t bytes, CoMutex *lock) |
| 47 | { |
| 48 | BlockReq *r = reqlist_find_conflict(reqs, offset, bytes); |
| 49 | |
| 50 | if (!r) { |
| 51 | return false; |
| 52 | } |
| 53 | |
| 54 | qemu_co_queue_wait(&r->wait_queue, lock); |
| 55 | |
| 56 | return true; |
| 57 | } |
| 58 | |
| 59 | void coroutine_fn reqlist_wait_all(BlockReqList *reqs, int64_t offset, |
| 60 | int64_t bytes, CoMutex *lock) |
| 61 | { |
| 62 | while (reqlist_wait_one(reqs, offset, bytes, lock)) { |
| 63 | /* continue */ |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | void coroutine_fn reqlist_shrink_req(BlockReq *req, int64_t new_bytes) |
| 68 | { |
| 69 | if (new_bytes == req->bytes) { |
| 70 | return; |
| 71 | } |
| 72 | |
| 73 | assert(new_bytes > 0 && new_bytes < req->bytes); |
| 74 | |
| 75 | req->bytes = new_bytes; |
| 76 | qemu_co_queue_restart_all(&req->wait_queue); |
| 77 | } |
| 78 | |
| 79 | void coroutine_fn reqlist_remove_req(BlockReq *req) |
| 80 | { |
| 81 | QLIST_REMOVE(req, list); |
| 82 | qemu_co_queue_restart_all(&req->wait_queue); |
| 83 | } |