rust: enable `clippy::as_underscore` lint

In Rust 1.63.0, Clippy introduced the `as_underscore` lint [1]:

> The conversion might include lossy conversion or a dangerous cast that
> might go undetected due to the type being inferred.
>
> The lint is allowed by default as using `_` is less wordy than always
> specifying the type.

Always specifying the type is especially helpful in function call
contexts where the inferred type may change at a distance. Specifying
the type also allows Clippy to spot more cases of `useless_conversion`.

The primary downside is the need to specify the type in trivial getters.
There are 4 such functions: 3 have become slightly less ergonomic, 1 was
revealed to be a `useless_conversion`.

While this doesn't eliminate unchecked `as` conversions, it makes such
conversions easier to scrutinize.  It also has the slight benefit of
removing a degree of freedom on which to bikeshed. Thus apply the
changes and enable the lint -- no functional change intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-4-f43b024581e8@gmail.com
[ Changed `isize` to `c_long`. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 26 insertions, 26 deletions

diff --git a/rust/kernel/mm/virt.rs b/rust/kernel/mm/virt.rs
index 31803674aecc..6086ca981b06 100644
--- a/rust/kernel/mm/virt.rs
+++ b/rust/kernel/mm/virt.rs
@@ -392,80 +392,80 @@ pub mod flags {
     use crate::bindings;
 
     /// No flags are set.
-    pub const NONE: vm_flags_t = bindings::VM_NONE as _;
+    pub const NONE: vm_flags_t = bindings::VM_NONE as vm_flags_t;
 
     /// Mapping allows reads.
-    pub const READ: vm_flags_t = bindings::VM_READ as _;
+    pub const READ: vm_flags_t = bindings::VM_READ as vm_flags_t;
 
     /// Mapping allows writes.
-    pub const WRITE: vm_flags_t = bindings::VM_WRITE as _;
+    pub const WRITE: vm_flags_t = bindings::VM_WRITE as vm_flags_t;
 
     /// Mapping allows execution.
-    pub const EXEC: vm_flags_t = bindings::VM_EXEC as _;
+    pub const EXEC: vm_flags_t = bindings::VM_EXEC as vm_flags_t;
 
     /// Mapping is shared.
-    pub const SHARED: vm_flags_t = bindings::VM_SHARED as _;
+    pub const SHARED: vm_flags_t = bindings::VM_SHARED as vm_flags_t;
 
     /// Mapping may be updated to allow reads.
-    pub const MAYREAD: vm_flags_t = bindings::VM_MAYREAD as _;
+    pub const MAYREAD: vm_flags_t = bindings::VM_MAYREAD as vm_flags_t;
 
     /// Mapping may be updated to allow writes.
-    pub const MAYWRITE: vm_flags_t = bindings::VM_MAYWRITE as _;
+    pub const MAYWRITE: vm_flags_t = bindings::VM_MAYWRITE as vm_flags_t;
 
     /// Mapping may be updated to allow execution.
-    pub const MAYEXEC: vm_flags_t = bindings::VM_MAYEXEC as _;
+    pub const MAYEXEC: vm_flags_t = bindings::VM_MAYEXEC as vm_flags_t;
 
     /// Mapping may be updated to be shared.
-    pub const MAYSHARE: vm_flags_t = bindings::VM_MAYSHARE as _;
+    pub const MAYSHARE: vm_flags_t = bindings::VM_MAYSHARE as vm_flags_t;
 
     /// Page-ranges managed without `struct page`, just pure PFN.
-    pub const PFNMAP: vm_flags_t = bindings::VM_PFNMAP as _;
+    pub const PFNMAP: vm_flags_t = bindings::VM_PFNMAP as vm_flags_t;
 
     /// Memory mapped I/O or similar.
-    pub const IO: vm_flags_t = bindings::VM_IO as _;
+    pub const IO: vm_flags_t = bindings::VM_IO as vm_flags_t;
 
     /// Do not copy this vma on fork.
-    pub const DONTCOPY: vm_flags_t = bindings::VM_DONTCOPY as _;
+    pub const DONTCOPY: vm_flags_t = bindings::VM_DONTCOPY as vm_flags_t;
 
     /// Cannot expand with mremap().
-    pub const DONTEXPAND: vm_flags_t = bindings::VM_DONTEXPAND as _;
+    pub const DONTEXPAND: vm_flags_t = bindings::VM_DONTEXPAND as vm_flags_t;
 
     /// Lock the pages covered when they are faulted in.
-    pub const LOCKONFAULT: vm_flags_t = bindings::VM_LOCKONFAULT as _;
+    pub const LOCKONFAULT: vm_flags_t = bindings::VM_LOCKONFAULT as vm_flags_t;
 
     /// Is a VM accounted object.
-    pub const ACCOUNT: vm_flags_t = bindings::VM_ACCOUNT as _;
+    pub const ACCOUNT: vm_flags_t = bindings::VM_ACCOUNT as vm_flags_t;
 
     /// Should the VM suppress accounting.
-    pub const NORESERVE: vm_flags_t = bindings::VM_NORESERVE as _;
+    pub const NORESERVE: vm_flags_t = bindings::VM_NORESERVE as vm_flags_t;
 
     /// Huge TLB Page VM.
-    pub const HUGETLB: vm_flags_t = bindings::VM_HUGETLB as _;
+    pub const HUGETLB: vm_flags_t = bindings::VM_HUGETLB as vm_flags_t;
 
     /// Synchronous page faults. (DAX-specific)
-    pub const SYNC: vm_flags_t = bindings::VM_SYNC as _;
+    pub const SYNC: vm_flags_t = bindings::VM_SYNC as vm_flags_t;
 
     /// Architecture-specific flag.
-    pub const ARCH_1: vm_flags_t = bindings::VM_ARCH_1 as _;
+    pub const ARCH_1: vm_flags_t = bindings::VM_ARCH_1 as vm_flags_t;
 
     /// Wipe VMA contents in child on fork.
-    pub const WIPEONFORK: vm_flags_t = bindings::VM_WIPEONFORK as _;
+    pub const WIPEONFORK: vm_flags_t = bindings::VM_WIPEONFORK as vm_flags_t;
 
     /// Do not include in the core dump.
-    pub const DONTDUMP: vm_flags_t = bindings::VM_DONTDUMP as _;
+    pub const DONTDUMP: vm_flags_t = bindings::VM_DONTDUMP as vm_flags_t;
 
     /// Not soft dirty clean area.
-    pub const SOFTDIRTY: vm_flags_t = bindings::VM_SOFTDIRTY as _;
+    pub const SOFTDIRTY: vm_flags_t = bindings::VM_SOFTDIRTY as vm_flags_t;
 
     /// Can contain `struct page` and pure PFN pages.
-    pub const MIXEDMAP: vm_flags_t = bindings::VM_MIXEDMAP as _;
+    pub const MIXEDMAP: vm_flags_t = bindings::VM_MIXEDMAP as vm_flags_t;
 
     /// MADV_HUGEPAGE marked this vma.
-    pub const HUGEPAGE: vm_flags_t = bindings::VM_HUGEPAGE as _;
+    pub const HUGEPAGE: vm_flags_t = bindings::VM_HUGEPAGE as vm_flags_t;
 
     /// MADV_NOHUGEPAGE marked this vma.
-    pub const NOHUGEPAGE: vm_flags_t = bindings::VM_NOHUGEPAGE as _;
+    pub const NOHUGEPAGE: vm_flags_t = bindings::VM_NOHUGEPAGE as vm_flags_t;
 
     /// KSM may merge identical pages.
-    pub const MERGEABLE: vm_flags_t = bindings::VM_MERGEABLE as _;
+    pub const MERGEABLE: vm_flags_t = bindings::VM_MERGEABLE as vm_flags_t;
 }