kargs: Update kargs computing function name

Rename the function `kargs_from_composefs_filesystem` to
`compute_new_kargs` as it now has nothing to do with composefs

Signed-off-by: Pragyan Poudyal <pragyanpoudyal41999@gmail.com>

Author: Johan-Liebert1

crates/lib/src/bootc_composefs/boot.rs

@@ -96,7 +96,7 @@ use rustix::{mount::MountFlags, path::Arg};
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 
-use crate::bootc_kargs::kargs_from_composefs_filesystem;
+use crate::bootc_kargs::compute_new_kargs;
 use crate::composefs_consts::{TYPE1_ENT_PATH, TYPE1_ENT_PATH_STAGED};
 use crate::parsers::bls_config::{BLSConfig, BLSConfigType};
 use crate::parsers::grub_menuconfig::MenuEntry;
@@ -564,7 +564,7 @@ pub(crate) fn setup_composefs_bls_boot(
         None
     };
 
-    kargs_from_composefs_filesystem(mounted_erofs, current_root, &mut cmdline_refs)?;
+    compute_new_kargs(mounted_erofs, current_root, &mut cmdline_refs)?;
 
     let (entry_paths, _tmpdir_guard) = match bootloader {
         Bootloader::Grub => {

crates/lib/src/bootc_kargs.rs

@@ -73,8 +73,22 @@ fn compute_apply_kargs_diff(
     }
 }
 
-/// Looks for files in usr/lib/bootc/kargs.d and parses cmdline agruments
-pub(crate) fn kargs_from_composefs_filesystem(
+/// Computes new kernel arguments by applying the diff between existing and new kargs.d files.
+///
+/// This function:
+/// 1. Loads kernel arguments from `usr/lib/bootc/kargs.d` in the new filesystem
+/// 2. Loads kernel arguments from the current root (if present)
+/// 3. Computes the difference between them (added/removed arguments)
+/// 4. Applies that difference to the provided `new_kargs` cmdline
+///
+/// This allows bootc to maintain user customizations while applying changes from
+/// updated container images.
+///
+/// # Arguments
+/// * `new_fs`       - Directory handle to the new filesystem containing kargs.d files
+/// * `current_root` - Optional directory handle to current root filesystem
+/// * `new_kargs`    - Mutable cmdline that will be modified with the computed diff
+pub(crate) fn compute_new_kargs(
     new_fs: &Dir,
     current_root: Option<&Dir>,
     new_kargs: &mut Cmdline,