From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38659) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fvjwd-0002Hy-Dn for qemu-devel@nongnu.org; Fri, 31 Aug 2018 09:58:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fvjwc-0003Vl-EG for qemu-devel@nongnu.org; Fri, 31 Aug 2018 09:58:39 -0400 Date: Fri, 31 Aug 2018 09:58:25 -0400 From: Jeff Cody Message-ID: <20180831135825.GF415265@localhost.localdomain> References: <20180830015734.19765-1-jsnow@redhat.com> <20180830015734.19765-5-jsnow@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180830015734.19765-5-jsnow@redhat.com> Subject: Re: [Qemu-devel] [PATCH v3 4/9] block/commit: utilize job_exit shim List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: John Snow Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, kwolf@redhat.com, Stefan Hajnoczi , Max Reitz On Wed, Aug 29, 2018 at 09:57:29PM -0400, John Snow wrote: > Change the manual deferment to commit_complete into the implicit > callback to job_exit, renaming commit_complete to commit_exit. > > This conversion does change the timing of when job_completed is > called to after the bdrv_replace_node and bdrv_unref calls, which > could have implications for bjob->blk which will now be put down > after this cleanup. > > Kevin highlights that we did not take any permissions for that backend > at job creation time, so it is safe to reorder these operations. > > Signed-off-by: John Snow > Reviewed-by: Max Reitz > --- > block/commit.c | 22 +++++----------------- > 1 file changed, 5 insertions(+), 17 deletions(-) > > diff --git a/block/commit.c b/block/commit.c > index 4a17bb73ec..da69165de3 100644 > --- a/block/commit.c > +++ b/block/commit.c > @@ -68,19 +68,13 @@ static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base, > return 0; > } > > -typedef struct { > - int ret; > -} CommitCompleteData; > - > -static void commit_complete(Job *job, void *opaque) > +static void commit_exit(Job *job) > { > CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); > BlockJob *bjob = &s->common; > - CommitCompleteData *data = opaque; > BlockDriverState *top = blk_bs(s->top); > BlockDriverState *base = blk_bs(s->base); > BlockDriverState *commit_top_bs = s->commit_top_bs; > - int ret = data->ret; > bool remove_commit_top_bs = false; > > /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */ > @@ -91,10 +85,10 @@ static void commit_complete(Job *job, void *opaque) > * the normal backing chain can be restored. */ > blk_unref(s->base); > > - if (!job_is_cancelled(job) && ret == 0) { > + if (!job_is_cancelled(job) && job->ret == 0) { > /* success */ > - ret = bdrv_drop_intermediate(s->commit_top_bs, base, > - s->backing_file_str); > + job->ret = bdrv_drop_intermediate(s->commit_top_bs, base, > + s->backing_file_str); > } else { > /* XXX Can (or should) we somehow keep 'consistent read' blocked even > * after the failed/cancelled commit job is gone? If we already wrote > @@ -117,9 +111,6 @@ static void commit_complete(Job *job, void *opaque) > * bdrv_set_backing_hd() to fail. */ > block_job_remove_all_bdrv(bjob); > > - job_completed(job, ret); > - g_free(data); > - Not having to allocate, track, and free this cumbersome return value for each of these job specific completions now is pretty nice. Reviewed-by: Jeff Cody > /* If bdrv_drop_intermediate() didn't already do that, remove the commit > * filter driver from the backing chain. Do this as the final step so that > * the 'consistent read' permission can be granted. */ > @@ -137,7 +128,6 @@ static void commit_complete(Job *job, void *opaque) > static int coroutine_fn commit_run(Job *job, Error **errp) > { > CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); > - CommitCompleteData *data; > int64_t offset; > uint64_t delay_ns = 0; > int ret = 0; > @@ -210,9 +200,6 @@ static int coroutine_fn commit_run(Job *job, Error **errp) > out: > qemu_vfree(buf); > > - data = g_malloc(sizeof(*data)); > - data->ret = ret; > - job_defer_to_main_loop(&s->common.job, commit_complete, data); > return ret; > } > > @@ -224,6 +211,7 @@ static const BlockJobDriver commit_job_driver = { > .user_resume = block_job_user_resume, > .drain = block_job_drain, > .run = commit_run, > + .exit = commit_exit, > }, > }; > > -- > 2.14.4 >