Re: [Qemu-devel] [PATCH v9 04/11] block: use the block job list in bdrv_close()

[Kevin Wolf <kwolf@redhat.com>]

Am 04.04.2016 um 15:43 hat Alberto Garcia geschrieben:
> bdrv_close_all() cancels all block jobs by iterating over all
> BlockDriverStates. This patch simplifies the code by iterating
> directly over the block jobs using block_job_next().
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>

This is essentially the same as I'm doing here:
http://repo.or.cz/qemu/kevin.git/commitdiff/6b545b21e3dfe2e3927cfb6bbdcc1b233c67630c

I think I like having a separate block_job_cancel_sync_all() function
like I did instead of inlining it in bdrv_close_all(), though that's a
matter of taste.

My patch also moves the call, so having to move only a single line in my
patch (assuming it gets rebased on top of this one) seems nicer.

Kevin

>  block.c | 25 ++++++-------------------
>  1 file changed, 6 insertions(+), 19 deletions(-)
> 
> diff --git a/block.c b/block.c
> index d36eb75..48638c9 100644
> --- a/block.c
> +++ b/block.c
> @@ -2182,8 +2182,7 @@ static void bdrv_close(BlockDriverState *bs)
>  
>  void bdrv_close_all(void)
>  {
> -    BlockDriverState *bs;
> -    AioContext *aio_context;
> +    BlockJob *job;
>  
>      /* Drop references from requests still in flight, such as canceled block
>       * jobs whose AIO context has not been polled yet */
> @@ -2193,23 +2192,11 @@ void bdrv_close_all(void)
>      blockdev_close_all_bdrv_states();
>  
>      /* Cancel all block jobs */
> -    while (!QTAILQ_EMPTY(&all_bdrv_states)) {
> -        QTAILQ_FOREACH(bs, &all_bdrv_states, bs_list) {
> -            aio_context = bdrv_get_aio_context(bs);
> -
> -            aio_context_acquire(aio_context);
> -            if (bs->job) {
> -                block_job_cancel_sync(bs->job);
> -                aio_context_release(aio_context);
> -                break;
> -            }
> -            aio_context_release(aio_context);
> -        }
> -
> -        /* All the remaining BlockDriverStates are referenced directly or
> -         * indirectly from block jobs, so there needs to be at least one BDS
> -         * directly used by a block job */
> -        assert(bs);
> +    while ((job = block_job_next(NULL))) {
> +        AioContext *aio_context = bdrv_get_aio_context(job->bs);
> +        aio_context_acquire(aio_context);
> +        block_job_cancel_sync(job);
> +        aio_context_release(aio_context);
>      }
>  }
>  
> -- 
> 2.8.0.rc3
>