1 | /* |
2 | * AioContext wait support |
3 | * |
4 | * Copyright (C) 2018 Red Hat, Inc. |
5 | * |
6 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
7 | * of this software and associated documentation files (the "Software"), to deal |
8 | * in the Software without restriction, including without limitation the rights |
9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
10 | * copies of the Software, and to permit persons to whom the Software is |
11 | * furnished to do so, subject to the following conditions: |
12 | * |
13 | * The above copyright notice and this permission notice shall be included in |
14 | * all copies or substantial portions of the Software. |
15 | * |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
22 | * THE SOFTWARE. |
23 | */ |
24 | |
25 | #include "qemu/osdep.h" |
26 | #include "qemu/main-loop.h" |
27 | #include "block/aio-wait.h" |
28 | |
29 | AioWait global_aio_wait; |
30 | |
31 | static void dummy_bh_cb(void *opaque) |
32 | { |
33 | /* The point is to make AIO_WAIT_WHILE()'s aio_poll() return */ |
34 | } |
35 | |
36 | void aio_wait_kick(void) |
37 | { |
38 | /* The barrier (or an atomic op) is in the caller. */ |
39 | if (atomic_read(&global_aio_wait.num_waiters)) { |
40 | aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL); |
41 | } |
42 | } |
43 | |
44 | typedef struct { |
45 | bool done; |
46 | QEMUBHFunc *cb; |
47 | void *opaque; |
48 | } AioWaitBHData; |
49 | |
50 | /* Context: BH in IOThread */ |
51 | static void aio_wait_bh(void *opaque) |
52 | { |
53 | AioWaitBHData *data = opaque; |
54 | |
55 | data->cb(data->opaque); |
56 | |
57 | data->done = true; |
58 | aio_wait_kick(); |
59 | } |
60 | |
61 | void aio_wait_bh_oneshot(AioContext *ctx, QEMUBHFunc *cb, void *opaque) |
62 | { |
63 | AioWaitBHData data = { |
64 | .cb = cb, |
65 | .opaque = opaque, |
66 | }; |
67 | |
68 | assert(qemu_get_current_aio_context() == qemu_get_aio_context()); |
69 | |
70 | aio_bh_schedule_oneshot(ctx, aio_wait_bh, &data); |
71 | AIO_WAIT_WHILE(ctx, !data.done); |
72 | } |
73 | |