xemu/include
Kevin Wolf 57e05be343 block: Call drain callbacks only once
We only need to call both the BlockDriver's callback and the parent
callbacks when going from undrained to drained or vice versa. A second
drain section doesn't make a difference for the driver or the parent,
they weren't supposed to send new requests before and after the second
drain.

One thing that gets in the way is the 'ignore_bds_parents' parameter in
bdrv_do_drained_begin_quiesce() and bdrv_do_drained_end(): It means that
bdrv_drain_all_begin() increases bs->quiesce_counter, but does not
quiesce the parent through BdrvChildClass callbacks. If an additional
drain section is started now, bs->quiesce_counter will be non-zero, but
we would still need to quiesce the parent through BdrvChildClass in
order to keep things consistent (and unquiesce it on the matching
bdrv_drained_end(), even though the counter would not reach 0 yet as
long as the bdrv_drain_all() section is still active).

Instead of keeping track of this, let's just get rid of the parameter.
It was introduced in commit 6cd5c9d7b2 as an optimisation so that
during bdrv_drain_all(), we wouldn't recursively drain all parents up to
the root for each node, resulting in quadratic complexity. As it happens,
calling the callbacks only once solves the same problem, so as of this
patch, we'll still have O(n) complexity and ignore_bds_parents is not
needed any more.

This patch only ignores the 'ignore_bds_parents' parameter. It will be
removed in a separate patch.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20221118174110.55183-12-kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-12-15 16:07:42 +01:00
..
authz Prefer 'on' | 'off' over 'yes' | 'no' for bool options 2021-01-29 17:07:53 +00:00
block block: Call drain callbacks only once 2022-12-15 16:07:42 +01:00
chardev chardev: src buffer const for write functions 2022-09-29 14:38:05 +04:00
crypto crypto: Support export akcipher to pkcs8 2022-11-02 06:56:32 -04:00
disas target/loongarch: Add disassembler 2022-06-06 18:09:03 +00:00
exec migration: Use non-atomic ops for clear log bitmap 2022-11-21 11:58:10 +01:00
fpu fpu: Add rebias bool, value and operation 2022-08-31 14:08:05 -03:00
hw cleanup: Tweak and re-run return_directly.cocci 2022-12-14 16:19:35 +01:00
io io: Tidy up fat-fingered parameter name 2022-12-14 16:19:35 +01:00
libdecnumber Replace config-time define HOST_WORDS_BIGENDIAN 2022-04-06 10:50:37 +02:00
migration migration: Remove load_state_old and minimum_version_id_old 2022-03-02 18:20:45 +00:00
monitor qapi misc: Elide redundant has_FOO in generated C 2022-12-14 20:04:47 +01:00
net Add G_GNUC_PRINTF to function qemu_set_info_str and fix related issues 2022-11-27 13:36:17 -05:00
qapi qerror: QERR_PERMISSION_DENIED is no longer used, drop 2022-10-27 07:57:18 +02:00
qemu qemu-config: Make config_parse_qdict() return bool 2022-12-14 16:19:35 +01:00
qom qom/object: Remove circular include dependency 2022-06-28 10:53:32 +02:00
scsi scsi-disk: add SCSI_DISK_QUIRK_MODE_PAGE_VENDOR_SPECIFIC_APPLE quirk for Macintosh 2022-07-13 16:58:58 +02:00
semihosting semihosting: Allow optional use of semihosting from userspace 2022-09-13 17:18:21 +01:00
standard-headers m68k: rework BI_VIRT_RNG_SEED as BI_RNG_SEED 2022-10-21 20:46:10 +02:00
sysemu cryptodev: Add a lkcf-backend for cryptodev 2022-11-02 06:56:32 -04:00
tcg accel/tcg: Introduce tb_pc and log_pc 2022-10-04 12:13:12 -07:00
ui ui/console: Get tab completion working again in the SDL monitor vc 2022-09-23 13:42:09 +02:00
user misc: fix commonly doubled up words 2022-08-01 11:58:02 +02:00
elf.h include/elf.h: add s390x note types 2022-10-26 12:54:59 +04:00
glib-compat.h compiler.h: replace QEMU_NORETURN with G_NORETURN 2022-04-21 17:03:51 +04:00
qemu-io.h Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
qemu-main.h ui/cocoa: Run qemu_init in the main thread 2022-09-23 14:36:33 +02:00