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| author | Emanuele Giuseppe Esposito <eesposit@redhat.com> | 2022-03-03 10:15:59 -0500 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2022-03-04 18:18:25 +0100 |
| commit | 696bf4c78c4640026c827c931a18385b687c66e8 (patch) | |
| tree | d984d5dd358d13399bc5f11cbe1d75437edba816 /include | |
| parent | 967d7905d1b568355c5422d595dd1e3a057c43f6 (diff) | |
| download | qemu-696bf4c78c4640026c827c931a18385b687c66e8.zip qemu-696bf4c78c4640026c827c931a18385b687c66e8.tar.gz qemu-696bf4c78c4640026c827c931a18385b687c66e8.tar.bz2 | |
block: introduce assert_bdrv_graph_writable
We want to be sure that the functions that write the child and
parent list of a bs are under BQL and drain.
BQL prevents from concurrent writings from the GS API, while
drains protect from I/O.
TODO: drains are missing in some functions using this assert.
Therefore a proper assertion will fail. Because adding drains
requires additional discussions, they will be added in future
series.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-15-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/block/block_int-global-state.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/include/block/block_int-global-state.h b/include/block/block_int-global-state.h index 5078d6a..0f21b05 100644 --- a/include/block/block_int-global-state.h +++ b/include/block/block_int-global-state.h @@ -309,4 +309,21 @@ void bdrv_remove_aio_context_notifier(BlockDriverState *bs, */ void bdrv_drain_all_end_quiesce(BlockDriverState *bs); +/** + * Make sure that the function is running under both drain and BQL. + * The latter protects from concurrent writings + * from the GS API, while the former prevents concurrent reads + * from I/O. + */ +static inline void assert_bdrv_graph_writable(BlockDriverState *bs) +{ + /* + * TODO: this function is incomplete. Because the users of this + * assert lack the necessary drains, check only for BQL. + * Once the necessary drains are added, + * assert also for qatomic_read(&bs->quiesce_counter) > 0 + */ + assert(qemu_in_main_thread()); +} + #endif /* BLOCK_INT_GLOBAL_STATE */ |