[PATCH 04/10] gpu: nova-core: gsp: cmdq: group the RPC-specific part of send_single_command

[Alexandre Courbot <acourbot@nvidia.com>]

`send_single_command` handles both the transport and message layers of
the command, intertwining the logic of the two.

Reorder the code so the message layer logic is within the same
contiguous block of code, so it can easily be moved.

No functional change intended.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpu/nova-core/gsp/cmdq.rs | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/nova-core/gsp/cmdq.rs b/drivers/gpu/nova-core/gsp/cmdq.rs
index 8e7e6609ebf1..f0e4f8f5228d 100644
--- a/drivers/gpu/nova-core/gsp/cmdq.rs
+++ b/drivers/gpu/nova-core/gsp/cmdq.rs
@@ -659,18 +659,21 @@ fn send_single_command<M>(&mut self, command: M) -> Result
             .gsp_mem
             .allocate_command(size_in_bytes, Self::ALLOCATE_TIMEOUT)?;
 
+        // Fill the header.
+        let msg_element_init = GspMsgElement::init(self.seq, size_in_bytes);
+        // SAFETY: `msg_header` is a valid reference, and not touched if the initializer fails.
+        unsafe {
+            pin_init::raw_try_init(core::ptr::from_mut(dst.header), msg_element_init)?;
+        }
+
         // Extract area for the command itself. The GSP message header and the command header
         // together are guaranteed to fit entirely into a single page, so it's ok to only look
         // at `dst.contents.0` here.
         let (cmd, payload_1) = M::Command::from_bytes_mut_prefix(dst.contents.0).ok_or(EIO)?;
-
-        // Fill the header and command in-place.
-        let msg_element_init = GspMsgElement::init(self.seq, size_in_bytes);
         let rpc_header_init = RpcMessageHeader::init(size_in_bytes, M::FUNCTION);
-        // SAFETY: `msg_header` and `cmd` are valid references, and not touched if the initializer
-        // fails.
+        // SAFETY: `rpc_header_mut()` and `cmd` are valid references, and not touched if the
+        // initializer fails.
         unsafe {
-            pin_init::raw_try_init(core::ptr::from_mut(dst.header), msg_element_init)?;
             pin_init::raw_try_init(
                 core::ptr::from_mut(dst.header.rpc_header_mut()),
                 rpc_header_init,
@@ -687,14 +690,6 @@ fn send_single_command<M>(&mut self, command: M) -> Result
         }
         drop(sbuffer);
 
-        // Compute checksum now that the whole message is ready.
-        dst.header
-            .set_checksum(Cmdq::calculate_checksum(SBufferIter::new_reader([
-                dst.header.as_bytes(),
-                dst.contents.0,
-                dst.contents.1,
-            ])));
-
         dev_dbg!(
             &self.dev,
             "GSP RPC: send: seq# {}, function={:?}, length=0x{:x}\n",
@@ -703,6 +698,14 @@ fn send_single_command<M>(&mut self, command: M) -> Result
             size_in_bytes,
         );
 
+        // Compute checksum now that the whole message is ready.
+        dst.header
+            .set_checksum(Cmdq::calculate_checksum(SBufferIter::new_reader([
+                dst.header.as_bytes(),
+                dst.contents.0,
+                dst.contents.1,
+            ])));
+
         // All set - update the write pointer and inform the GSP of the new command.
         let elem_count = dst.header.element_count();
         self.seq += 1;

-- 
2.55.0