From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40608) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YXvhD-0006U2-3E for qemu-devel@nongnu.org; Tue, 17 Mar 2015 13:54:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YXvhB-0001Lx-VM for qemu-devel@nongnu.org; Tue, 17 Mar 2015 13:54:26 -0400 Message-ID: <55086A4A.6030409@redhat.com> Date: Tue, 17 Mar 2015 13:54:18 -0400 From: Max Reitz MIME-Version: 1.0 References: <1425528911-10300-1-git-send-email-jsnow@redhat.com> <1425528911-10300-5-git-send-email-jsnow@redhat.com> In-Reply-To: <1425528911-10300-5-git-send-email-jsnow@redhat.com> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 04/11] block: add refcount to Job object List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: John Snow , qemu-block@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, vsementsov@parallels.com, stefanha@redhat.com On 2015-03-04 at 23:15, John Snow wrote: > If we want to get at the job after the life of the job, > we'll need a refcount for this object. > > This may occur for example if we wish to inspect the actions > taken by a particular job after a transactional group of jobs > runs, and further actions are required. > > Signed-off-by: John Snow > --- > blockjob.c | 18 ++++++++++++++++-- > include/block/blockjob.h | 21 +++++++++++++++++++++ > 2 files changed, 37 insertions(+), 2 deletions(-) > > diff --git a/blockjob.c b/blockjob.c > index ba2255d..d620082 100644 > --- a/blockjob.c > +++ b/blockjob.c > @@ -35,6 +35,19 @@ > #include "qemu/timer.h" > #include "qapi-event.h" > > +void block_job_incref(BlockJob *job) > +{ > + job->refcount++; > +} > + > +void block_job_decref(BlockJob *job) > +{ > + job->refcount--; > + if (job->refcount == 0) { > + g_free(job); > + } > +} > + > void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, > int64_t speed, BlockCompletionFunc *cb, > void *opaque, Error **errp) > @@ -57,6 +70,7 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, > job->cb = cb; > job->opaque = opaque; > job->busy = true; > + job->refcount = 1; > bs->job = job; > > /* Only set speed when necessary to avoid NotSupported error */ > @@ -68,7 +82,7 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, > bs->job = NULL; > bdrv_op_unblock_all(bs, job->blocker); > error_free(job->blocker); > - g_free(job); > + block_job_decref(job); > error_propagate(errp, local_err); > return NULL; > } > @@ -85,7 +99,7 @@ void block_job_completed(BlockJob *job, int ret) > bs->job = NULL; > bdrv_op_unblock_all(bs, job->blocker); > error_free(job->blocker); > - g_free(job); > + block_job_decref(job); > } > > void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp) > diff --git a/include/block/blockjob.h b/include/block/blockjob.h > index b6d4ebb..8fe1c95 100644 > --- a/include/block/blockjob.h > +++ b/include/block/blockjob.h > @@ -116,6 +116,9 @@ struct BlockJob { > > /** The opaque value that is passed to the completion function. */ > void *opaque; > + > + /** A reference count, allowing for post-job actions in e.g. transactions */ > + int refcount; > }; > > /** > @@ -141,6 +144,24 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs, > void *opaque, Error **errp); > > /** > + * block_job_incref: > + * @job: The job to pick up a handle to > + * > + * Increment the refcount on @job, to be able to use it asynchronously > + * from the job it is being used for. Put down the reference when done > + * with @block_job_unref Missing a full stop? With that added: Reviewed-by: Max Reitz > + */ > +void block_job_incref(BlockJob *job); > + > +/** > + * block_job_decref: > + * @job: The job to unreference and delete. > + * > + * Decrement the refcount on @job, and delete it if there are no users. (and also with that changed to "if it becomes/reaches zero", if you'd like, because somehow the "users" sounds unrelated to a party holding a refcount, when in fact it's supposed to be exactly the same thing; up to you) > + */ > +void block_job_decref(BlockJob *job); > + > +/** > * block_job_sleep_ns: > * @job: The job that calls the function. > * @clock: The clock to sleep on.