Re: [Qemu-devel] [PATCH 1/3] block: add BlockBackend->in_flight counter

[Eric Blake]

On 02/08/2018 11:18 AM, Stefan Hajnoczi wrote:
> BlockBackend currently relies on BlockDriverState->in_flight to track
> requests for blk_drain().  There is a corner case where
> BlockDriverState->in_flight cannot be used though: blk->root can be NULL
> when there is no medium.  This results in a segfault when the NULL
> pointer is dereferenced.
>
> Introduce a BlockBackend->in_flight counter for aio requests so it works
> even when blk->root == NULL.
>
> Based on a patch by Kevin Wolf <address@hidden>.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
>   block.c               |  2 +-
>   block/block-backend.c | 59 +++++++++++++++++++++++++++++++++++++++++++++------
>   2 files changed, 53 insertions(+), 8 deletions(-)

Reviewed-by: Eric Blake <address@hidden>

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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