From: Baineng Shou <shoubaineng@gmail.com>
To: Sumit Semwal <sumit.semwal@linaro.org>,
	=?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
	"T . J . Mercier" <tjmercier@google.com>,
	Benjamin Gaignard <benjamin.gaignard@collabora.com>,
	Brian Starkey <Brian.Starkey@arm.com>,
	John Stultz <jstultz@google.com>,
	Sandeep Patil <sspatil@android.com>,
	"Andrew F . Davis" <afd@ti.com>,
	Srinivas Kandagatla <srini@kernel.org>,
	David Airlie <airlied@gmail.com>,
	Simona Vetter <simona@ffwll.ch>
Cc: stable@vger.kernel.org,
	dri-devel@lists.freedesktop.org,
	linux-media@vger.kernel.org,
	linaro-mm-sig@lists.linaro.org,
	linux-kernel@vger.kernel.org,
	linux-arm-msm@vger.kernel.org,
	Baineng Shou <shoubaineng@gmail.com>
Subject: [PATCH v5 3/4] drm/prime: use dma_buf_fd_install() to preserve export tracing
Date: Thu, 30 Jul 2026 14:26:44 +0800
Message-Id: <20260730062645.233148-4-shoubaineng@gmail.com>
In-Reply-To: <20260730062645.233148-1-shoubaineng@gmail.com>
References: <CAO_48GGxJj6AU6vsu-Y18WKtL_9RT=zsXWp3L+ifZdLM7CgGtw@mail.gmail.com>
 <20260730062645.233148-1-shoubaineng@gmail.com>
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drm_gem_prime_handle_to_fd() open-codes fd reservation and install
using get_unused_fd_flags() + fd_install() directly.  This bypasses
the DMA_BUF_TRACE() call that dma_buf_fd() emits, so observability
tools relying on the trace_dma_buf_fd tracepoint silently miss all
DRM PRIME exports.

Replace the bare fd_install() with dma_buf_fd_install(), which wraps
fd_install() together with DMA_BUF_TRACE(), restoring full tracepoint
coverage.  No functional change; the fd lifecycle (get_unused_fd_flags
→ work → install) is already correct.

Note: this patch depends on dma_buf_fd_install() introduced in
"dma-buf: dma-heap: don't publish fd before copy_to_user() succeeds"
[1].

[1] https://lore.kernel.org/dri-devel/20260714114654.3885457-2-shoubaineng@gmail.com/

Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Baineng Shou <shoubaineng@gmail.com>
---
 drivers/gpu/drm/drm_prime.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 9b44c78cd77f..fe3436d1235d 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -524,7 +524,7 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 		return PTR_ERR(dmabuf);
 	}
 
-	fd_install(fd, dmabuf->file);
+	dma_buf_fd_install(dmabuf, fd);
 	*prime_fd = fd;
 	return 0;
 }
-- 
2.34.1