Re: [PATCH 1/2] block-backend: Allow concurrent context changes

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Fri, Feb 02, 2024 at 03:47:54PM +0100, Hanna Czenczek wrote:
> Since AioContext locks have been removed, a BlockBackend's AioContext
> may really change at any time (only exception is that it is often
> confined to a drained section, as noted in this patch).  Therefore,
> blk_get_aio_context() cannot rely on its root node's context always
> matching that of the BlockBackend.
> 
> In practice, whether they match does not matter anymore anyway: Requests
> can be sent to BDSs from any context, so anyone who requests the BB's
> context should have no reason to require the root node to have the same
> context.  Therefore, we can and should remove the assertion to that
> effect.
> 
> In addition, because the context can be set and queried from different
> threads concurrently, it has to be accessed with atomic operations.
> 
> Buglink: https://issues.redhat.com/browse/RHEL-19381
> Suggested-by: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
> ---
>  block/block-backend.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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