From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gustavo Padovan Subject: Re: [RFC v2 3/3] dma-buf/sync_file: rework fence storage in struct file Date: Tue, 28 Jun 2016 11:25:00 -0300 Message-ID: <20160628142500.GK2508@joana> References: <1467055762-25881-1-git-send-email-gustavo@padovan.org> <1467055762-25881-4-git-send-email-gustavo@padovan.org> <20160628080221.GB25424@nuc-i3427.alporthouse.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <20160628080221.GB25424@nuc-i3427.alporthouse.com> Sender: linux-kernel-owner@vger.kernel.org To: Chris Wilson , Gustavo Padovan , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Stone , Daniel Vetter , Rob Clark , Greg Hackmann , John Harrison , laurent.pinchart@ideasonboard.com, seanpaul@google.com, marcheu@google.com, m.chehab@samsung.com, Sumit Semwal , Maarten Lankhorst , Gustavo Padovan , Christian =?iso-8859-1?Q?K=F6nig?= List-Id: dri-devel@lists.freedesktop.org 2016-06-28 Chris Wilson : > On Mon, Jun 27, 2016 at 04:29:22PM -0300, Gustavo Padovan wrote: > > From: Gustavo Padovan > >=20 > > Create sync_file->fence to abstract the type of fence we are using = for > > each sync_file. If only one fence is present we use a normal struct= fence > > but if there is more fences to be added to the sync_file a fence_ar= ray > > is created. > >=20 > > This change cleans up sync_file a bit. We don't need to have sync_f= ile_cb > > array anymore. Instead, as we always have one fence, only one fenc= e > > callback is registered per sync_file. > >=20 > > Cc: Chris Wilson > > Cc: Christian K=F6nig > > Signed-off-by: Gustavo Padovan > > --- > > @@ -76,21 +76,19 @@ struct sync_file *sync_file_create(struct fence= *fence) > > { > > struct sync_file *sync_file; > > =20 > > - sync_file =3D sync_file_alloc(offsetof(struct sync_file, cbs[1]))= ; > > + sync_file =3D sync_file_alloc(); > > if (!sync_file) > > return NULL; > > =20 > > - sync_file->num_fences =3D 1; > > + sync_file->fence =3D fence; > > + > > atomic_set(&sync_file->status, 1); >=20 > sync_file->status =3D> fence_is_signaled(sync_file->fence); >=20 > Both should just be an atomic read, except fence_is_signaled() will t= hen > do a secondary poll. Not sure I follow. I set it to 1 here, but below when we call fence_add_callback() and the fence is already signalled atomic_dec sets sync_file->status to 0. >=20 > > snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%llu-%d"= , > > fence->ops->get_driver_name(fence), > > fence->ops->get_timeline_name(fence), fence->context, > > fence->seqno); > > =20 > > - sync_file->cbs[0].fence =3D fence; > > - sync_file->cbs[0].sync_file =3D sync_file; > > - if (fence_add_callback(fence, &sync_file->cbs[0].cb, > > - fence_check_cb_func)) > > + if (fence_add_callback(fence, &sync_file->cb, fence_check_cb_func= )) > > atomic_dec(&sync_file->status); > > =20 > > return sync_file; > > @@ -121,14 +119,42 @@ err: > > return NULL; > > } > > =20 > > -static void sync_file_add_pt(struct sync_file *sync_file, int *i, > > - struct fence *fence) > > +static int sync_file_set_fence(struct sync_file *sync_file, > > + struct fence **fences, int num_fences) > > { > > - sync_file->cbs[*i].fence =3D fence; > > - sync_file->cbs[*i].sync_file =3D sync_file; > > + struct fence_array *array; > > + > > + if (num_fences =3D=3D 1) { > > + sync_file->fence =3D fences[0]; >=20 > This steals the references. >=20 > > + } else { > > + array =3D fence_array_create(num_fences, fences, > > + fence_context_alloc(1), 1, false); >=20 > This creates a reference. >=20 > When we call fence_put(sync_fence->fence) we release a reference we > never owned if num_fences =3D=3D 1. No, sync_file_merge() gets a new reference for each fence it is going t= o add to the new fence. So for num_fences =3D=3D 1 when sync_file->fence = is set we already hold a reference to it, so no matter if it is a fence or a array we own a reference. >=20 > > + struct fence **fences, **a_fences, **b_fences; > > + int i, i_a, i_b, num_fences, a_num_fences, b_num_fences; > > =20 > > + a_fences =3D get_fences(a, &a_num_fences); > > + b_fences =3D get_fences(b, &b_num_fences); > > + num_fences =3D a_num_fences + b_num_fences; > > + > > + fences =3D kcalloc(num_fences, sizeof(**fences), GFP_KERNEL); >=20 > Just sizeof(*fences) (you want to allocate an array of pointers, not = an > array of fence structs). Okay. Gustavo