hvf: x86: Remove unused definitions
[qemu.git] / block / write-threshold.c
blob85b78dc2a9bd590d54746f02f188814f8e9dbcca
1 /*
2 * QEMU System Emulator block write threshold notification
4 * Copyright Red Hat, Inc. 2014
6 * Authors:
7 * Francesco Romani <fromani@redhat.com>
9 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
10 * See the COPYING.LIB file in the top-level directory.
13 #include "qemu/osdep.h"
14 #include "block/block_int.h"
15 #include "qemu/coroutine.h"
16 #include "block/write-threshold.h"
17 #include "qemu/notify.h"
18 #include "qapi/error.h"
19 #include "qapi/qapi-commands-block-core.h"
20 #include "qapi/qapi-events-block-core.h"
22 uint64_t bdrv_write_threshold_get(const BlockDriverState *bs)
24 return bs->write_threshold_offset;
27 bool bdrv_write_threshold_is_set(const BlockDriverState *bs)
29 return bs->write_threshold_offset > 0;
32 static void write_threshold_disable(BlockDriverState *bs)
34 if (bdrv_write_threshold_is_set(bs)) {
35 notifier_with_return_remove(&bs->write_threshold_notifier);
36 bs->write_threshold_offset = 0;
40 uint64_t bdrv_write_threshold_exceeded(const BlockDriverState *bs,
41 const BdrvTrackedRequest *req)
43 if (bdrv_write_threshold_is_set(bs)) {
44 if (req->offset > bs->write_threshold_offset) {
45 return (req->offset - bs->write_threshold_offset) + req->bytes;
47 if ((req->offset + req->bytes) > bs->write_threshold_offset) {
48 return (req->offset + req->bytes) - bs->write_threshold_offset;
51 return 0;
54 static int coroutine_fn before_write_notify(NotifierWithReturn *notifier,
55 void *opaque)
57 BdrvTrackedRequest *req = opaque;
58 BlockDriverState *bs = req->bs;
59 uint64_t amount = 0;
61 amount = bdrv_write_threshold_exceeded(bs, req);
62 if (amount > 0) {
63 qapi_event_send_block_write_threshold(
64 bs->node_name,
65 amount,
66 bs->write_threshold_offset);
68 /* autodisable to avoid flooding the monitor */
69 write_threshold_disable(bs);
72 return 0; /* should always let other notifiers run */
75 static void write_threshold_register_notifier(BlockDriverState *bs)
77 bs->write_threshold_notifier.notify = before_write_notify;
78 bdrv_add_before_write_notifier(bs, &bs->write_threshold_notifier);
81 static void write_threshold_update(BlockDriverState *bs,
82 int64_t threshold_bytes)
84 bs->write_threshold_offset = threshold_bytes;
87 void bdrv_write_threshold_set(BlockDriverState *bs, uint64_t threshold_bytes)
89 if (bdrv_write_threshold_is_set(bs)) {
90 if (threshold_bytes > 0) {
91 write_threshold_update(bs, threshold_bytes);
92 } else {
93 write_threshold_disable(bs);
95 } else {
96 if (threshold_bytes > 0) {
97 /* avoid multiple registration */
98 write_threshold_register_notifier(bs);
99 write_threshold_update(bs, threshold_bytes);
101 /* discard bogus disable request */
105 void qmp_block_set_write_threshold(const char *node_name,
106 uint64_t threshold_bytes,
107 Error **errp)
109 BlockDriverState *bs;
110 AioContext *aio_context;
112 bs = bdrv_find_node(node_name);
113 if (!bs) {
114 error_setg(errp, "Device '%s' not found", node_name);
115 return;
118 aio_context = bdrv_get_aio_context(bs);
119 aio_context_acquire(aio_context);
121 bdrv_write_threshold_set(bs, threshold_bytes);
123 aio_context_release(aio_context);