[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH v2 0/3] block: Start/end drain on correct AioContext
From: |
Hanna Reitz |
Subject: |
[PATCH v2 0/3] block: Start/end drain on correct AioContext |
Date: |
Mon, 7 Nov 2022 16:13:18 +0100 |
Hi,
v1 cover letter:
https://lists.nongnu.org/archive/html/qemu-block/2022-09/msg00389.html
bdrv_replace_child_noperm() drains the child via
bdrv_parent_drained_{begin,end}_single(). When it removes a child, the
bdrv_parent_drained_end_single() at its end will be called on an empty
child, making the BDRV_POLL_WHILE() in it poll the main AioContext
(because c->bs is NULL).
Thatâs wrong, though, because itâs supposed to operate on the parent.
bdrv_parent_drained_end_single_no_poll() will have scheduled any BHs in
the parentsâ AioContext, which may be anything, not necessarily the main
context. Therefore, we must poll the parentâs context.
Patch 3 does this for both bdrv_parent_drained_{begin,end}_single().
Patch 1 ensures that we can legally call
bdrv_child_get_parent_aio_context() from those I/O context functions,
and patch 2 fixes blk_do_set_aio_context() to not cause an assertion
failure if it beginning a drain can end up in blk_get_aio_context()
before blk->ctx has been updated.
v2:
- Patch 1:
- Move bdrv_child_get_parent_aio_context() from block-global-state.h
to block-io.h
- Move BdrvChildClass.get_parent_aio_context into the I/O code section
- Mark blk_root_get_parent_aio_context() as I/O code
- Mark child_job_get_parent_aio_context(), and lock the job mutex,
which we now need to do (as of 3ed4f708fe1)
- Patch 2:
- Added comment similar to Kevinâs suggestion
(Still decided to take Kevinâs R-b, even though I didnât use the
literal suggestion, but made it a bit more verbose)
Hanna Reitz (3):
block: Make bdrv_child_get_parent_aio_context I/O
block-backend: Update ctx immediately after root
block: Start/end drain on correct AioContext
include/block/block-global-state.h | 1 -
include/block/block-io.h | 2 ++
include/block/block_int-common.h | 4 ++--
block.c | 2 +-
block/block-backend.c | 9 ++++++++-
block/io.c | 6 ++++--
blockjob.c | 3 ++-
7 files changed, 19 insertions(+), 8 deletions(-)
--
2.36.1
- [PATCH v2 0/3] block: Start/end drain on correct AioContext,
Hanna Reitz <=
- [PATCH v2 1/3] block: Make bdrv_child_get_parent_aio_context I/O, Hanna Reitz, 2022/11/07
- [PATCH v2 2/3] block-backend: Update ctx immediately after root, Hanna Reitz, 2022/11/07
- [PATCH v2 3/3] block: Start/end drain on correct AioContext, Hanna Reitz, 2022/11/07
- Re: [PATCH v2 0/3] block: Start/end drain on correct AioContext, Kevin Wolf, 2022/11/08
- Re: [PATCH v2 0/3] block: Start/end drain on correct AioContext, Kevin Wolf, 2022/11/10