[RFC PATCH 4/9] rust: dma_fence: expose the fence's seqno publically

From: "Maíra Canal" <mcanal@igalia.com>
To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
	Miguel Ojeda <ojeda@kernel.org>,
	Alex Gaynor <alex.gaynor@gmail.com>,
	Wedson Almeida Filho <wedsonaf@gmail.com>,
	Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
	Asahi Lina <lina@asahilina.net>,
	Faith Ekstrand <faith.ekstrand@collabora.com>
Cc: "Melissa Wen" <mwen@igalia.com>,
	"Maíra Canal" <mcanal@igalia.com>,
	dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org
Subject: [RFC PATCH 4/9] rust: dma_fence: expose the fence's seqno publically
Date: Fri, 17 Mar 2023 09:12:08 -0300	[thread overview]
Message-ID: <20230317121213.93991-5-mcanal@igalia.com> (raw)
In-Reply-To: <20230317121213.93991-1-mcanal@igalia.com>

Each fence has a linear increasing sequence number inside the execution
context, that can be used to decide which fence would be signaled later.
So, expose this attribute to the Rust drivers through a method.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
---
 rust/kernel/dma_fence.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/rust/kernel/dma_fence.rs b/rust/kernel/dma_fence.rs
index 176e6d250e6c..94fead520274 100644
--- a/rust/kernel/dma_fence.rs
+++ b/rust/kernel/dma_fence.rs
@@ -60,6 +60,13 @@ pub trait RawDmaFence: crate::private::Sealed {
         }
     }
 
+    /// Return the seqno from this fence
+    fn seqno(&self) -> u64 {
+        // SAFETY: We hold a reference to a dma_fence and every dma_fence holds
+        // a seqno.
+        unsafe { (*self.raw()).seqno }
+    }
+
     /// Signal completion of this fence
     fn signal(&self) -> Result {
         to_result(unsafe { bindings::dma_fence_signal(self.raw()) })
-- 
2.39.2

