From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757008AbcGJJP7 (ORCPT ); Sun, 10 Jul 2016 05:15:59 -0400 Received: from mga11.intel.com ([192.55.52.93]:23234 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750824AbcGJJP5 (ORCPT ); Sun, 10 Jul 2016 05:15:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,340,1464678000"; d="scan'208";a="732095424" Subject: Re: [PATCH] dma-buf/sync_file: only enable fence signalling during wait To: Gustavo Padovan , dri-devel@lists.freedesktop.org References: <1467992691-12442-1-git-send-email-gustavo@padovan.org> Cc: 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 , Gustavo Padovan From: Maarten Lankhorst Message-ID: <183b15e0-3072-6aa2-7d35-002c20752e0e@linux.intel.com> Date: Sun, 10 Jul 2016 11:15:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <1467992691-12442-1-git-send-email-gustavo@padovan.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Op 08-07-16 om 17:44 schreef Gustavo Padovan: > From: Gustavo Padovan > > Signalling doesn't need to be enabled at sync_file creation, it is only > required if userspace waiting the fence to signal through poll(). > > Thus we delay fence_add_callback() until poll is called. It only adds the > callback the first time poll() is called. This avoid re-adding the same > callback multiple times. > > v2: rebase and update to work with new fence support for sync_file > > Signed-off-by: Gustavo Padovan > --- > This patch applies on top of my latest sync_file changes to support > fence_array: https://lkml.org/lkml/2016/7/4/534 > > drivers/dma-buf/sync_file.c | 23 ++++++++++++++--------- > include/linux/sync_file.h | 2 ++ > 2 files changed, 16 insertions(+), 9 deletions(-) > > diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c > index 61a687c..1db4a64 100644 > --- a/drivers/dma-buf/sync_file.c > +++ b/drivers/dma-buf/sync_file.c > @@ -86,8 +86,6 @@ struct sync_file *sync_file_create(struct fence *fence) > fence->ops->get_timeline_name(fence), fence->context, > fence->seqno); > > - fence_add_callback(fence, &sync_file->cb, fence_check_cb_func); > - > return sync_file; > } > EXPORT_SYMBOL(sync_file_create); > @@ -269,9 +267,6 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a, > goto err; > } > > - fence_add_callback(sync_file->fence, &sync_file->cb, > - fence_check_cb_func); > - > strlcpy(sync_file->name, name, sizeof(sync_file->name)); > return sync_file; > > @@ -286,7 +281,6 @@ static void sync_file_free(struct kref *kref) > struct sync_file *sync_file = container_of(kref, struct sync_file, > kref); > > - fence_remove_callback(sync_file->fence, &sync_file->cb); > fence_put(sync_file->fence); > kfree(sync_file); > } > @@ -306,13 +300,24 @@ static unsigned int sync_file_poll(struct file *file, poll_table *wait) > > poll_wait(file, &sync_file->wq, wait); > > + if (!sync_file->enabled) { > + fence_add_callback(sync_file->fence, &sync_file->cb, > + fence_check_cb_func); > + sync_file->enabled = true; > + } Won't this blow up completely with 2 threads polling at the same time? ~Maarten