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From: Kees Cook <keescook@chromium.org>
To: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
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Subject: [PATCH 2/5] drm/vmwgfx: Do not directly manipulate file->f_count
Date: Thu,  2 May 2024 15:33:37 -0700
Message-Id: <20240502223341.1835070-2-keescook@chromium.org>
In-Reply-To: <20240502222252.work.690-kees@kernel.org>
References: <20240502222252.work.690-kees@kernel.org>
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The correct helper for taking an f_count reference is get_file().
Now that it checks for 0 counts, use it and check results.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
Cc: Zack Rusin <zack.rusin@broadcom.com>
Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@broadcom.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
---
 drivers/gpu/drm/vmwgfx/ttm_object.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vmwgfx/ttm_object.c b/drivers/gpu/drm/vmwgfx/ttm_object.c
index 6806c05e57f6..68d8ee3020b1 100644
--- a/drivers/gpu/drm/vmwgfx/ttm_object.c
+++ b/drivers/gpu/drm/vmwgfx/ttm_object.c
@@ -475,7 +475,7 @@ void ttm_object_device_release(struct ttm_object_device **p_tdev)
  */
 static bool __must_check get_dma_buf_unless_doomed(struct dma_buf *dmabuf)
 {
-	return atomic_long_inc_not_zero(&dmabuf->file->f_count) != 0L;
+	return get_file(dmabuf->file) != NULL;
 }
 
 /**
-- 
2.34.1