rust: optimize mlx4 driver basic

rust/kernel/lib.rs

@@ -76,6 +76,7 @@ pub mod task;
 pub mod workqueue;
 
 pub mod linked_list;
+#[cfg(CONFIG_MLX4_EN)]
 pub mod mlx4;
 mod raw_list;
 pub mod rbtree;

rust/kernel/mlx4.rs

@@ -1,42 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Infiniband mlx4 devices.
+//!
+
 use alloc::boxed::Box;
-use cm::CmWorkQueue;
 use core::pin::Pin;
-use core::{cell::UnsafeCell, marker, ptr};
+use core::{marker, ptr};
 use macros::vtable;
-use mcg::McgWorkQueue;
-use qp::QpWorkQueue;
 
-use crate::error::{code::*, Error, Result};
+use crate::bindings;
+use crate::error::{code::*, Result};
 use crate::str::CStr;
 use crate::workqueue::{BoxedQueue, Queue};
-use crate::{bindings, pr_info};
 
-mod cm;
-mod mcg;
-mod qp;
-
-/// Soft RDMA transport registration.
+/// Infiband mlx4 device registration.
 ///
 pub struct Registration<T: Mlx4Operation> {
     registered: bool,
+    #[allow(dead_code)]
     name: &'static CStr,
-
     wq: Mlx4WorkQueue,
     cm_wq: CmWorkQueue,
     qp_wq: QpWorkQueue,
     mcg_wq: McgWorkQueue,
     phantom: marker::PhantomData<T>,
-    //rxe_link_ops: bindings::rdma_link_ops,
-    //再包一层
-    //_pin: PhantomPinned,
-
-    // /// Context initialised on construction and made available to all file instances on
-    // /// [`file::Operations::open`].
-    //open_data: MaybeUninit<T::OpenData>,
 }
 
 impl<T: Mlx4Operation> Registration<T> {
+    /// Creates a new [`Registration`] but does not register it yet.
+    ///
+    /// It is allowed to move.
     pub fn new(name: &'static CStr) -> Self {
+        // INVARIANT: `registered` is `false`
         Self {
             registered: false,
             name,
@@ -45,18 +40,29 @@ impl<T: Mlx4Operation> Registration<T> {
             qp_wq: QpWorkQueue::new(),
             mcg_wq: McgWorkQueue::new(),
             phantom: marker::PhantomData,
-            //rxe_link_ops:bindings::rdma_link_ops::default(),
         }
     }
 
+    /// Registers a infiband mlx4 device.
+    ///
+    /// Returns a pinned heap-allocated representation of the registration.
     pub fn new_pinned(name: &'static CStr) -> Result<Pin<Box<Self>>> {
         let mut r = Pin::from(Box::try_new(Self::new(name))?);
         r.as_mut().register()?;
         Ok(r)
     }
 
+    // Registers a infiband mlx4 device with the rest of the kernel.
+    ///
+    /// It must be pinned because the memory block that represents the registration is
+    /// self-referential.
     pub fn register(self: Pin<&mut Self>) -> Result {
+        // SAFETY: We must ensure that we never move out of `this`.
         let this = unsafe { self.get_unchecked_mut() };
+        if this.registered {
+            // Already registered.
+            return Err(EINVAL);
+        }
 
         match this.wq.init() {
             Ok(()) => {}
@@ -90,8 +96,7 @@ impl<T: Mlx4Operation> Registration<T> {
             }
         }
 
-        // interface用vtable替换掉
-
+        // SAFETY: The adapter is compatible with the mlx4 register
         unsafe {
             bindings::mlx4_register_interface(Mlx4OperationTable::<T>::build());
         }
@@ -102,9 +107,9 @@ impl<T: Mlx4Operation> Registration<T> {
 }
 
 impl<T: Mlx4Operation> Drop for Registration<T> {
+    /// Removes the registration from the kernel if it has completed successfully before.
     fn drop(&mut self) {
         if self.registered {
-            //unsafe{bindings::mlx4_unregister_interface();}
             self.mcg_wq.clean();
             self.cm_wq.clean();
             self.qp_wq.clean();
@@ -113,9 +118,15 @@ impl<T: Mlx4Operation> Drop for Registration<T> {
     }
 }
 
+/// Build kernel's `struct mlx4_interface` type with mlx4 device operation.
 pub struct Mlx4OperationTable<T>(marker::PhantomData<T>);
 
 impl<T: Mlx4Operation> Mlx4OperationTable<T> {
+    /// Builds an instance of [`struct mlx4_interface`].
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that the adapter is compatible with the way the device is registered.
     pub fn build() -> *mut bindings::mlx4_interface {
         return &mut bindings::mlx4_interface {
             add: Some(Self::add_callback),
@@ -134,58 +145,39 @@ impl<T: Mlx4Operation> Mlx4OperationTable<T> {
         };
     }
 
-    unsafe extern "C" fn add_callback(dev: *mut bindings::mlx4_dev) -> *mut core::ffi::c_void {
+    unsafe extern "C" fn add_callback(_dev: *mut bindings::mlx4_dev) -> *mut core::ffi::c_void {
+        let _ = T::add();
         return ptr::null_mut();
     }
 
     unsafe extern "C" fn remove_callback(
-        dev: *mut bindings::mlx4_dev,
-        context: *mut core::ffi::c_void,
+        _dev: *mut bindings::mlx4_dev,
+        _context: *mut core::ffi::c_void,
     ) {
+        let _ = T::remove();
     }
 
     unsafe extern "C" fn event_callback(
-        dev: *mut bindings::mlx4_dev,
-        context: *mut core::ffi::c_void,
-        event: bindings::mlx4_dev_event,
-        param: core::ffi::c_ulong,
+        _dev: *mut bindings::mlx4_dev,
+        _context: *mut core::ffi::c_void,
+        _event: bindings::mlx4_dev_event,
+        _param: core::ffi::c_ulong,
     ) {
+        let _ = T::event();
     }
-
-    // unsafe extern "C" fn get_dev_callback(
-    //     dev: *mut mlx4_dev,
-    //     context: *mut core::ffi::c_void,
-    //     port: u8_,
-    // ) -> *mut core::ffi::c_void {
-    // }
-
-    // unsafe extern "C" fn activate_callback(
-    //     dev: *mut mlx4_dev,
-    //     context: *mut core::ffi::c_void
-    // ) {
-    // }
-
-    // MLX4FUNC:bindings::mlx4_interface=bindings::mlx4_interface {
-    //     add:Some(Self::add_callback),
-    //     remove:Some(Self::remove_callback),
-    //     event:Some(Self::event_callback),
-    //     get_dev:None,
-    //     activate:None,
-    //     list:bindings::list_head{next:ptr::null_mut(),prev:ptr::null_mut()},
-    //     // MLX4_PROT_IB_IPV6
-    //     protocol:0,
-    //     // MLX4_INTFF_BONDING
-    //     flags:1,
-    // };
 }
 
+/// Corresponds to the kernel's `struct mlx4_interface`.
+///
+/// You implement this trait whenever you would create a `struct mlx4_interface`.
 #[vtable]
 pub trait Mlx4Operation {
-    fn add();
-    fn remove();
-    fn event();
-    // fn get_dev();
-    // fn activate();
+    /// Add a new mlx4 ib device.
+    fn add() -> Result;
+    /// Remove mlx4 ib device.
+    fn remove() -> Result;
+    /// Respond to specific mlx4 ib device event
+    fn event() -> Result;
 }
 
 pub(crate) struct Mlx4WorkQueue {
@@ -213,3 +205,84 @@ impl Mlx4WorkQueue {
         }
     }
 }
+
+pub(crate) struct CmWorkQueue {
+    cm_wq: Option<BoxedQueue>,
+}
+
+impl CmWorkQueue {
+    pub(crate) fn new() -> Self {
+        Self { cm_wq: None }
+    }
+
+    pub(crate) fn init(&mut self) -> Result {
+        let cm_wq_tmp = Queue::try_new(format_args!("mlx4_ib_cm"), 0, 0);
+        self.cm_wq = match cm_wq_tmp {
+            Ok(cm_wq) => Some(cm_wq),
+            Err(e) => return Err(e),
+        };
+
+        Ok(())
+    }
+
+    pub(crate) fn clean(&mut self) {
+        if self.cm_wq.is_some() {
+            drop(self.cm_wq.take().unwrap());
+        }
+    }
+}
+
+pub(crate) struct McgWorkQueue {
+    clean_wq: Option<BoxedQueue>,
+}
+
+impl McgWorkQueue {
+    pub(crate) fn new() -> Self {
+        Self { clean_wq: None }
+    }
+
+    pub(crate) fn init(&mut self) -> Result {
+        let clean_wq_tmp = Queue::try_new(format_args!("mlx4_ib_mcg"), 655369, 1);
+        self.clean_wq = match clean_wq_tmp {
+            Ok(clean_wq) => Some(clean_wq),
+            Err(e) => return Err(e),
+        };
+
+        Ok(())
+    }
+
+    pub(crate) fn clean(&mut self) {
+        if self.clean_wq.is_some() {
+            drop(self.clean_wq.take().unwrap());
+        }
+    }
+}
+
+pub(crate) struct QpWorkQueue {
+    mlx4_ib_qp_event_wq: Option<BoxedQueue>,
+}
+
+impl QpWorkQueue {
+    pub(crate) fn new() -> Self {
+        Self {
+            mlx4_ib_qp_event_wq: None,
+        }
+    }
+
+    pub(crate) fn init(&mut self) -> Result {
+        let mlx4_ib_qp_event_wq_tmp =
+            Queue::try_new(format_args!("mlx4_ib_qp_event_wq"), 655361, 1);
+        self.mlx4_ib_qp_event_wq = match mlx4_ib_qp_event_wq_tmp {
+            Ok(mlx4_ib_qp_event_wq) => Some(mlx4_ib_qp_event_wq),
+            Err(e) => return Err(e),
+        };
+
+        Ok(())
+    }
+
+    pub(crate) fn clean(&mut self) {
+        if self.mlx4_ib_qp_event_wq.is_some() {
+            drop(self.mlx4_ib_qp_event_wq.take().unwrap());
+        }
+    }
+}

rust/kernel/workqueue.rs

@@ -408,6 +408,9 @@ pub struct BoxedQueue {
     ptr: NonNull<Queue>,
 }
 
+// SAFETY: Kernel workqueues are usable from any thread.
+unsafe impl Sync for BoxedQueue {}
+
 impl BoxedQueue {
     /// Creates a new instance of [`BoxedQueue`].
     ///