[PATCH 5/5] rust: fs: use READ_ONCE instead of read_volatile

[Alice Ryhl]

Using `READ_ONCE` is the correct way to read the `f_flags` field.

Signed-off-by: Alice Ryhl <aliceryhl at google.com>
---
 rust/kernel/fs/file.rs | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/rust/kernel/fs/file.rs b/rust/kernel/fs/file.rs
index 23ee689bd2400565223181645157d832a836589f..6b07f08e7012f512e53743266096ce0076d29e1c 100644
--- a/rust/kernel/fs/file.rs
+++ b/rust/kernel/fs/file.rs
@@ -335,12 +335,8 @@ pub fn cred(&self) -> &Credential {
     /// The flags are a combination of the constants in [`flags`].
     #[inline]
     pub fn flags(&self) -> u32 {
-        // This `read_volatile` is intended to correspond to a READ_ONCE call.
-        //
-        // SAFETY: The file is valid because the shared reference guarantees a nonzero refcount.
-        //
-        // FIXME(read_once): Replace with `read_once` when available on the Rust side.
-        unsafe { core::ptr::addr_of!((*self.as_ptr()).f_flags).read_volatile() }
+        // SAFETY: The `f_flags` field of `struct file` is readable with `READ_ONCE`.
+        unsafe { kernel::sync::READ_ONCE(&raw const (*self.as_ptr()).f_flags) }
     }
 }
 

-- 
2.52.0.351.gbe84eed79e-goog