linux-kernel - [PATCH 4/6] dma-buf: Don't misuse dma_fence

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Message-ID: <20251126131914.149445-6-phasta@kernel.org>
Date: Wed, 26 Nov 2025 14:19:13 +0100
From: Philipp Stanner <phasta@...nel.org>
To: Sumit Semwal <sumit.semwal@...aro.org>,
	Gustavo Padovan <gustavo@...ovan.org>,
	Christian König <christian.koenig@....com>,
	Felix Kuehling <Felix.Kuehling@....com>,
	Alex Deucher <alexander.deucher@....com>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Jani Nikula <jani.nikula@...ux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@...el.com>,
	Tvrtko Ursulin <tursulin@...ulin.net>,
	Huang Rui <ray.huang@....com>,
	Matthew Auld <matthew.auld@...el.com>,
	Matthew Brost <matthew.brost@...el.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	Lucas De Marchi <lucas.demarchi@...el.com>,
	Thomas Hellström <thomas.hellstrom@...ux.intel.com>
Cc: linux-media@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linaro-mm-sig@...ts.linaro.org,
	linux-kernel@...r.kernel.org,
	amd-gfx@...ts.freedesktop.org,
	intel-gfx@...ts.freedesktop.org,
	intel-xe@...ts.freedesktop.org,
	rust-for-linux@...r.kernel.org,
	Philipp Stanner <phasta@...nel.org>
Subject: [PATCH 4/6] dma-buf: Don't misuse dma_fence_signal()

The return code of dma_fence_signal() is not really useful as there is
nothing reasonable to do if a fence was already signaled. That return
code shall be removed from the kernel.

Moreover, dma_fence_signal() should not be used to check whether fences
are signaled. That's what dma_fence_is_signaled() and
dma_fence_test_signaled_flag() exist for.

Replace the non-canonical usage of dma_fence_signal().

Suggested-by: Christian König <christian.koenig@....com>
Signed-off-by: Philipp Stanner <phasta@...nel.org>
---
 drivers/dma-buf/st-dma-fence.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/dma-buf/st-dma-fence.c b/drivers/dma-buf/st-dma-fence.c
index 27a36045410b..9fc93859f36f 100644
--- a/drivers/dma-buf/st-dma-fence.c
+++ b/drivers/dma-buf/st-dma-fence.c
@@ -126,17 +126,14 @@ static int test_signaling(void *arg)
 		goto err_free;
 	}
 
-	if (dma_fence_signal(f)) {
-		pr_err("Fence reported being already signaled\n");
-		goto err_free;
-	}
+	dma_fence_signal(f);
 
 	if (!dma_fence_is_signaled(f)) {
 		pr_err("Fence not reporting signaled\n");
 		goto err_free;
 	}
 
-	if (!dma_fence_signal(f)) {
+	if (!dma_fence_test_signaled_flag(f)) {
 		pr_err("Fence reported not being already signaled\n");
 		goto err_free;
 	}
-- 
2.49.0