Op 08-07-16 om 17:44 schreef Gustavo Padovan: > From: Gustavo Padovan <gustavo.pado...@collabora.co.uk> > > 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 <gustavo.pado...@collabora.co.uk> > --- > 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
