[PATCH v3 3/5] gpu: nova-core: gsp: use empty slices instead of [0..0] ranges

[Eliot Courtney <ecourtney@nvidia.com>]

The current code unnecessarily uses, for example, &before_rx[0..0] to
return an empty slice. Instead, just use an empty slice.

Signed-off-by: Eliot Courtney <ecourtney@nvidia.com>
---
 drivers/gpu/nova-core/gsp/cmdq.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/nova-core/gsp/cmdq.rs b/drivers/gpu/nova-core/gsp/cmdq.rs
index 0743597779f1..b88ff8ebc098 100644
--- a/drivers/gpu/nova-core/gsp/cmdq.rs
+++ b/drivers/gpu/nova-core/gsp/cmdq.rs
@@ -232,7 +232,7 @@ fn new(dev: &device::Device<device::Bound>) -> Result<Self> {
             // to `rx`, minus one unit, belongs to the driver.
             if rx == 0 {
                 let last = after_tx.len() - 1;
-                (&mut after_tx[..last], &mut before_tx[0..0])
+                (&mut after_tx[..last], &mut [])
             } else {
                 (after_tx, &mut before_tx[..rx])
             }
@@ -241,7 +241,7 @@ fn new(dev: &device::Device<device::Bound>) -> Result<Self> {
             //
             // PANIC: per the invariants of `cpu_write_ptr` and `gsp_read_ptr`, `rx` and `tx` are
             // `<= MSGQ_NUM_PAGES`, and the test above ensured that `rx > tx`.
-            (after_tx.split_at_mut(rx - tx).0, &mut before_tx[0..0])
+            (after_tx.split_at_mut(rx - tx).0, &mut [])
         }
     }
 
@@ -263,8 +263,8 @@ fn new(dev: &device::Device<device::Bound>) -> Result<Self> {
         let (before_rx, after_rx) = gsp_mem.gspq.msgq.data.split_at(rx);
 
         match tx.cmp(&rx) {
-            cmp::Ordering::Equal => (&after_rx[0..0], &after_rx[0..0]),
-            cmp::Ordering::Greater => (&after_rx[..tx], &before_rx[0..0]),
+            cmp::Ordering::Equal => (&[], &[]),
+            cmp::Ordering::Greater => (&after_rx[..tx], &[]),
             cmp::Ordering::Less => (after_rx, &before_rx[..tx]),
         }
     }

-- 
2.52.0