[PATCH 15/80] rust: kernel: add count_paren_items macro, needed by define_fs_params macro

[Ariel Miculas <amiculas@cisco.com>]

Changes:
* add count_paren_items in rust/kernel/driver.rs, used by
  define_fs_params macro in rust/kernel/fs/param.rs
* add missing uring_cmd_iopoll in file_operations VTABLE
* fix accesses to the vm_flags field in vm_area_struct
* fix init's signature in rust/kernel/fs.rs
* import module_fs in samples/rust/rust_fs.rs

Signed-off-by: Ariel Miculas <amiculas@cisco.com>
---
 rust/bindings/bindings_helper.h |  1 +
 rust/kernel/driver.rs           | 28 ++++++++++++++++++++++++++++
 rust/kernel/file.rs             |  1 +
 rust/kernel/fs.rs               |  2 +-
 rust/kernel/lib.rs              |  3 ++-
 rust/kernel/mm.rs               |  4 ++--
 samples/rust/rust_fs.rs         |  1 +
 7 files changed, 36 insertions(+), 4 deletions(-)
 create mode 100644 rust/kernel/driver.rs

diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index d15a698439e1..6182174663ba 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -16,6 +16,7 @@
 #include <linux/poll.h>
 #include <linux/uio.h>
 #include <linux/uaccess.h>
+#include <linux/delay.h>
 
 /* `bindgen` gets confused at certain things. */
 const gfp_t BINDINGS_GFP_KERNEL = GFP_KERNEL;
diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs
new file mode 100644
index 000000000000..f743fcf5451b
--- /dev/null
+++ b/rust/kernel/driver.rs
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Generic support for drivers of different buses (e.g., PCI, Platform, Amba, etc.).
+//!
+//! Each bus/subsystem is expected to implement [`DriverOps`], which allows drivers to register
+//! using the [`Registration`] class.
+
+/// Counts the number of parenthesis-delimited, comma-separated items.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::count_paren_items;
+///
+/// assert_eq!(0, count_paren_items!());
+/// assert_eq!(1, count_paren_items!((A)));
+/// assert_eq!(1, count_paren_items!((A),));
+/// assert_eq!(2, count_paren_items!((A), (B)));
+/// assert_eq!(2, count_paren_items!((A), (B),));
+/// assert_eq!(3, count_paren_items!((A), (B), (C)));
+/// assert_eq!(3, count_paren_items!((A), (B), (C),));
+/// ```
+#[macro_export]
+macro_rules! count_paren_items {
+    (($($item:tt)*), $($remaining:tt)*) => { 1 + $crate::count_paren_items!($($remaining)*) };
+    (($($item:tt)*)) => { 1 };
+    () => { 0 };
+}
diff --git a/rust/kernel/file.rs b/rust/kernel/file.rs
index 586c0b386b5b..b3bbbf153925 100644
--- a/rust/kernel/file.rs
+++ b/rust/kernel/file.rs
@@ -637,6 +637,7 @@ impl<A: OpenAdapter<T::OpenData>, T: Operations> OperationsVtable<A, T> {
             None
         },
         uring_cmd: None,
+        uring_cmd_iopoll: None,
         write_iter: if T::HAS_WRITE {
             Some(Self::write_iter_callback)
         } else {
diff --git a/rust/kernel/fs.rs b/rust/kernel/fs.rs
index 1d920fde4022..ba98ae7caf00 100644
--- a/rust/kernel/fs.rs
+++ b/rust/kernel/fs.rs
@@ -1263,7 +1263,7 @@ pub struct Module<T: Type> {
 }
 
 impl<T: Type + Sync> crate::Module for Module<T> {
-    fn init(_name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+    fn init(module: &'static ThisModule) -> Result<Self> {
         let mut reg = Pin::from(Box::try_new(Registration::new())?);
         reg.as_mut().register::<T>(module)?;
         Ok(Self {
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 7dfebbe39430..08f67833afcf 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -21,6 +21,7 @@
 #![feature(receiver_trait)]
 #![feature(unsize)]
 #![feature(const_mut_refs)]
+#![feature(duration_constants)]
 
 // Ensure conditional compilation based on the kernel configuration works;
 // otherwise we may silently break things like initcall handling.
@@ -36,6 +37,7 @@
 mod build_assert;
 pub mod cred;
 pub mod delay;
+pub mod driver;
 pub mod error;
 pub mod file;
 pub mod fs;
@@ -97,7 +99,6 @@ impl ThisModule {
     pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
         ThisModule(ptr)
     }
-
 }
 /// Calculates the offset of a field from the beginning of the struct it belongs to.
 ///
diff --git a/rust/kernel/mm.rs b/rust/kernel/mm.rs
index 779359d0c5cf..d159c45157a9 100644
--- a/rust/kernel/mm.rs
+++ b/rust/kernel/mm.rs
@@ -38,7 +38,7 @@ pub(crate) unsafe fn from_ptr(vma: *mut bindings::vm_area_struct) -> Self {
         /// The possible flags are a combination of the constants in [`flags`].
         pub fn flags(&self) -> usize {
             // SAFETY: `self.vma` is valid by the type invariants.
-            unsafe { (*self.vma).vm_flags as _ }
+            unsafe { (*self.vma).__bindgen_anon_1.vm_flags as _ }
         }
 
         /// Sets the flags associated with the virtual memory area.
@@ -46,7 +46,7 @@ pub fn flags(&self) -> usize {
         /// The possible flags are a combination of the constants in [`flags`].
         pub fn set_flags(&mut self, flags: usize) {
             // SAFETY: `self.vma` is valid by the type invariants.
-            unsafe { (*self.vma).vm_flags = flags as _ };
+            unsafe { (*self.vma).__bindgen_anon_1.vm_flags = flags as _ };
         }
 
         /// Returns the start address of the virtual memory area.
diff --git a/samples/rust/rust_fs.rs b/samples/rust/rust_fs.rs
index 18fd4542863b..7527681ee024 100644
--- a/samples/rust/rust_fs.rs
+++ b/samples/rust/rust_fs.rs
@@ -2,6 +2,7 @@
 
 //! Rust file system sample.
 
+use kernel::module_fs;
 use kernel::prelude::*;
 use kernel::{c_str, file, fs, io_buffer::IoBufferWriter};
 
-- 
2.40.1