[PATCH] gpu: nova-core: take advantage of pci::Device::unbind()

[Danilo Krummrich <dakr@kernel.org>]

Now that we have pci::Device::unbind() we can unregister the sysmem
flush page with a direct access the I/O resource, i.e. without RCU read
side critical section.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 drivers/gpu/nova-core/driver.rs |  4 ++++
 drivers/gpu/nova-core/gpu.rs    | 20 ++++++++++----------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs
index 274989ea1fb4..02514e1e2529 100644
--- a/drivers/gpu/nova-core/driver.rs
+++ b/drivers/gpu/nova-core/driver.rs
@@ -54,4 +54,8 @@ fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> Result<Pin<KBox<Self
 
         Ok(this)
     }
+
+    fn unbind(pdev: &pci::Device<Core>, this: Pin<&Self>) {
+        this.gpu.unbind(pdev);
+    }
 }
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 8caecaf7dfb4..2db9afdc6087 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -163,7 +163,7 @@ fn new(bar: &Bar0) -> Result<Spec> {
 }
 
 /// Structure holding the resources required to operate the GPU.
-#[pin_data(PinnedDrop)]
+#[pin_data]
 pub(crate) struct Gpu {
     spec: Spec,
     /// MMIO mapping of PCI BAR 0
@@ -174,15 +174,6 @@ pub(crate) struct Gpu {
     sysmem_flush: SysmemFlush,
 }
 
-#[pinned_drop]
-impl PinnedDrop for Gpu {
-    fn drop(self: Pin<&mut Self>) {
-        // Unregister the sysmem flush page before we release it.
-        self.bar
-            .try_access_with(|b| self.sysmem_flush.unregister(b));
-    }
-}
-
 impl Gpu {
     /// Helper function to load and run the FWSEC-FRTS firmware and confirm that it has properly
     /// created the WPR2 region.
@@ -309,4 +300,13 @@ pub(crate) fn new(
             sysmem_flush,
         }))
     }
+
+    pub(crate) fn unbind(&self, pdev: &pci::Device<device::Bound>) {
+        // Unregister the sysmem flush page before we release it.
+        kernel::warn_on!(self.bar.access(pdev.as_ref()).map_or(true, |bar| {
+            self.sysmem_flush.unregister(bar);
+
+            false
+        }));
+    }
 }

base-commit: 09f90256e8902793f594517ef440698585eb3595
-- 
2.51.0