| Message ID | 20210702111642.17259-2-christian.koenig@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] dma-buf: add some more kerneldoc to dma_resv_add_shared_fence | expand |
On Fri, Jul 02, 2021 at 01:16:39PM +0200, Christian König wrote: > Explicitly document that code can't assume that shared fences > signal after the exclusive fence. > > Signed-off-by: Christian König <christian.koenig@amd.com> > --- > drivers/dma-buf/dma-resv.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c > index f26c71747d43..4ab02b6c387a 100644 > --- a/drivers/dma-buf/dma-resv.c > +++ b/drivers/dma-buf/dma-resv.c > @@ -235,7 +235,10 @@ EXPORT_SYMBOL(dma_resv_reset_shared_max); > * @fence: the shared fence to add > * > * Add a fence to a shared slot, obj->lock must be held, and > - * dma_resv_reserve_shared() has been called. > + * dma_resv_reserve_shared() has been called. The shared fences can signal in > + * any order and there is especially no guarantee that shared fences signal > + * after the exclusive one. Code relying on any signaling order is broken and > + * needs to be fixed. This feels like the last place I'd go look for how I should handle dependencies. It's the function for adding shared fences after all, has absolutely nothing to do with whether we should wait for them. I'll type up something else. -Daniel > */ > void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence) > { > -- > 2.25.1 >
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index f26c71747d43..4ab02b6c387a 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -235,7 +235,10 @@ EXPORT_SYMBOL(dma_resv_reset_shared_max); * @fence: the shared fence to add * * Add a fence to a shared slot, obj->lock must be held, and - * dma_resv_reserve_shared() has been called. + * dma_resv_reserve_shared() has been called. The shared fences can signal in + * any order and there is especially no guarantee that shared fences signal + * after the exclusive one. Code relying on any signaling order is broken and + * needs to be fixed. */ void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence) {
Explicitly document that code can't assume that shared fences signal after the exclusive fence. Signed-off-by: Christian König <christian.koenig@amd.com> --- drivers/dma-buf/dma-resv.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)