Hi Ezequiel, On Wed, 2018-05-09 at 17:14 -0300, Ezequiel Garcia wrote: > Change how dma_fence_add_callback() behaves, when the fence > has error-signaled by the time it is being add. After this commit, > dma_fence_add_callback() returns the fence error, if it > has error-signaled before dma_fence_add_callback() is called. > > Signed-off-by: Ezequiel Garcia <ezequ...@collabora.com> > --- > drivers/dma-buf/dma-fence.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma- > fence.c > index 4edb9fd3cf47..298b440c5b68 100644 > --- a/drivers/dma-buf/dma-fence.c > +++ b/drivers/dma-buf/dma-fence.c > @@ -226,7 +226,8 @@ EXPORT_SYMBOL(dma_fence_enable_sw_signaling); > * > * Note that the callback can be called from an atomic context. If > * fence is already signaled, this function will return -ENOENT (and > - * *not* call the callback) > + * *not* call the callback). If the fence is error-signaled, this > + * function returns the fence error. > * > * Add a software callback to the fence. Same restrictions apply to > * refcount as it does to dma_fence_wait, however the caller doesn't > need to > @@ -235,8 +236,8 @@ EXPORT_SYMBOL(dma_fence_enable_sw_signaling); > * after it signals with dma_fence_signal. The callback itself can > be called > * from irq context. > * > - * Returns 0 in case of success, -ENOENT if the fence is already > signaled > - * and -EINVAL in case of error. > + * Returns 0 in case of success, -ENOENT (or the error value) if the > fence is > + * already signaled and -EINVAL in case of error. > */ > int dma_fence_add_callback(struct dma_fence *fence, struct > dma_fence_cb *cb, > dma_fence_func_t func) > @@ -250,7 +251,8 @@ int dma_fence_add_callback(struct dma_fence > *fence, struct dma_fence_cb *cb, > > if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) { > INIT_LIST_HEAD(&cb->node); > - return -ENOENT; > + ret = (fence->error < 0) ? fence->error : -ENOENT; > + return ret; > }
It looks good to me, but I'd first go check all place we call it in the kernel because I have some memory of callers relying on the -ENOENT return code for some decision. I might be wrong though. Regards, Gustavo