gpu: nova-core: use CStr::from_bytes_until_nul() and remove util.rs

The util.rs module contained a single helper function,
str_from_null_terminated(), which duplicated functionality that is now
available in core::ffi::CStr.

Specifically, CStr::from_bytes_until_nul() is available in the kernel's
minimum supported Rust version (1.78.0), so it time to stop using this
custom workaround.

Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Link: https://patch.msgid.link/20260106035226.48853-2-jhubbard@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

3 files changed, 3 insertions, 19 deletions

diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index 0425c65b5d6f..a11fe6018091 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -30,7 +30,6 @@ use crate::{
         },
     },
     sbuffer::SBufferIter,
-    util,
 };
 
 /// The `GspSetSystemInfo` command.
@@ -209,7 +208,9 @@ impl GetGspStaticInfoReply {
     /// Returns the name of the GPU as a string, or `None` if the string given by the GSP was
     /// invalid.
     pub(crate) fn gpu_name(&self) -> Option<&str> {
-        util::str_from_null_terminated(&self.gpu_name)
+        CStr::from_bytes_until_nul(&self.gpu_name)
+            .ok()
+            .and_then(|cstr| cstr.to_str().ok())
     }
 }
 
diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index b98a1c03f13d..c1121e7c64c5 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -16,7 +16,6 @@ mod gsp;
 mod num;
 mod regs;
 mod sbuffer;
-mod util;
 mod vbios;
 
 pub(crate) const MODULE_NAME: &kernel::str::CStr = <LocalModule as kernel::ModuleMetadata>::NAME;
diff --git a/drivers/gpu/nova-core/util.rs b/drivers/gpu/nova-core/util.rs
deleted file mode 100644
index 4b503249a3ef..000000000000
--- a/drivers/gpu/nova-core/util.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-/// Converts a null-terminated byte slice to a string, or `None` if the array does not
-/// contains any null byte or contains invalid characters.
-///
-/// Contrary to [`kernel::str::CStr::from_bytes_with_nul`], the null byte can be anywhere in the
-/// slice, and not only in the last position.
-pub(crate) fn str_from_null_terminated(bytes: &[u8]) -> Option<&str> {
-    use kernel::str::CStr;
-
-    bytes
-        .iter()
-        .position(|&b| b == 0)
-        .and_then(|null_pos| CStr::from_bytes_with_nul(&bytes[..=null_pos]).ok())
-        .and_then(|cstr| cstr.to_str().ok())
-}