From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:41519 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751226AbdKUO1e (ORCPT ); Tue, 21 Nov 2017 09:27:34 -0500 Reply-To: christian.koenig@amd.com Subject: Re: [PATCH] reservation: don't wait when timeout=0 To: Rob Clark , dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org References: <20171121140850.23401-1-robdclark@gmail.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: <52253a44-112a-9bcb-bceb-2ea53a444265@gmail.com> Date: Tue, 21 Nov 2017 15:27:26 +0100 MIME-Version: 1.0 In-Reply-To: <20171121140850.23401-1-robdclark@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-media-owner@vger.kernel.org List-ID: Am 21.11.2017 um 15:08 schrieb Rob Clark: > If we are testing if a reservation object's fences have been > signaled with timeout=0 (non-blocking), we need to pass 0 for > timeout to dma_fence_wait_timeout(). > > Plus bonus spelling correction. > > Signed-off-by: Rob Clark Reviewed-by: Christian König > --- > drivers/dma-buf/reservation.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c > index dec3a815455d..71f51140a9ad 100644 > --- a/drivers/dma-buf/reservation.c > +++ b/drivers/dma-buf/reservation.c > @@ -420,7 +420,7 @@ EXPORT_SYMBOL_GPL(reservation_object_get_fences_rcu); > * > * RETURNS > * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or > - * greater than zer on success. > + * greater than zero on success. > */ > long reservation_object_wait_timeout_rcu(struct reservation_object *obj, > bool wait_all, bool intr, > @@ -483,7 +483,14 @@ long reservation_object_wait_timeout_rcu(struct reservation_object *obj, > goto retry; > } > > - ret = dma_fence_wait_timeout(fence, intr, ret); > + /* > + * Note that dma_fence_wait_timeout() will return 1 if > + * the fence is already signaled, so in the wait_all > + * case when we go through the retry loop again, ret > + * will be greater than 0 and we don't want this to > + * cause _wait_timeout() to block > + */ > + ret = dma_fence_wait_timeout(fence, intr, timeout ? ret : 0); > dma_fence_put(fence); > if (ret > 0 && wait_all && (i + 1 < shared_count)) > goto retry;