From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: Roman Kagan <rvkagan@yandex-team.ru>, qemu-devel@nongnu.org
Cc: yc-core@yandex-team.ru, Eric Blake <eblake@redhat.com>,
Max Reitz <mreitz@redhat.com>, Kevin Wolf <kwolf@redhat.com>,
qemu-block@nongnu.org
Subject: Re: [PATCH 7/7] block/nbd: stop manipulating in_flight counter
Date: Mon, 15 Mar 2021 23:15:44 +0300 [thread overview]
Message-ID: <de4fd61f-ccd3-125b-b636-aa06efe5823a@virtuozzo.com> (raw)
In-Reply-To: <20210315060611.2989049-8-rvkagan@yandex-team.ru>
15.03.2021 09:06, Roman Kagan wrote:
> As the reconnect logic no longer interferes with drained sections, it
> appears unnecessary to explicitly manipulate the in_flight counter.
>
> Fixes: 5ad81b4946 ("nbd: Restrict connection_co reentrance")
And here you actually allow qemu_aio_coroutine_enter() call in nbd_client_attach_aio_context_bh() to enter connection_co in any yield point which is possible during drained section. The analysis should be done to be sure that all these yield points are safe for reentering by external qemu_aio_coroutine_enter(). (By external I mean not by the actual enter() we are waiting for at the yield() point. For example qemu_channel_yield() supports reentering.. And therefore (as I understand after fast looking through) nbd_read() should support reentering too..
--
Best regards,
Vladimir
next prev parent reply other threads:[~2021-03-15 20:17 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-15 6:06 [PATCH 0/7] block/nbd: decouple reconnect from drain Roman Kagan
2021-03-15 6:06 ` [PATCH 1/7] block/nbd: avoid touching freed connect_thread Roman Kagan
2021-03-15 15:40 ` Vladimir Sementsov-Ogievskiy
2021-03-16 15:29 ` Roman Kagan
2021-04-06 16:21 ` Vladimir Sementsov-Ogievskiy
2021-03-15 6:06 ` [PATCH 2/7] block/nbd: use uniformly nbd_client_connecting_wait Roman Kagan
2021-03-15 15:48 ` Vladimir Sementsov-Ogievskiy
2021-03-15 6:06 ` [PATCH 3/7] block/nbd: assert attach/detach runs in the proper context Roman Kagan
2021-03-15 16:41 ` Vladimir Sementsov-Ogievskiy
2021-03-15 19:57 ` Roman Kagan
2021-03-15 6:06 ` [PATCH 4/7] block/nbd: transfer reconnection stuff across aio_context switch Roman Kagan
2021-03-15 6:06 ` [PATCH 5/7] block/nbd: better document a case in nbd_co_establish_connection Roman Kagan
2021-03-15 6:06 ` [PATCH 6/7] block/nbd: decouple reconnect from drain Roman Kagan
2021-03-15 20:10 ` Vladimir Sementsov-Ogievskiy
2021-03-16 16:03 ` Roman Kagan
2021-03-16 18:09 ` Vladimir Sementsov-Ogievskiy
2021-03-26 6:16 ` Roman Kagan
2021-03-15 6:06 ` [PATCH 7/7] block/nbd: stop manipulating in_flight counter Roman Kagan
2021-03-15 20:15 ` Vladimir Sementsov-Ogievskiy [this message]
2021-03-16 16:08 ` Roman Kagan
2021-03-16 18:37 ` Vladimir Sementsov-Ogievskiy
2021-03-26 7:41 ` Roman Kagan
2021-03-15 19:45 ` [PATCH 0/7] block/nbd: decouple reconnect from drain Vladimir Sementsov-Ogievskiy
2021-03-16 15:52 ` Roman Kagan
2021-03-16 14:41 ` Eric Blake
2021-03-16 16:10 ` Roman Kagan
2021-03-17 8:35 ` Vladimir Sementsov-Ogievskiy
2021-03-26 8:07 ` Roman Kagan
2021-04-07 7:45 ` Roman Kagan
2021-04-07 10:13 ` Vladimir Sementsov-Ogievskiy
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