Add infiniband mlx4 device driver basic interface

Documentation/process/changes.rst

@@ -32,7 +32,7 @@ you probably needn't concern yourself with pcmciautils.
 GNU C                  5.1              gcc --version
 Clang/LLVM (optional)  11.0.0           clang --version
 Rust (optional)        1.71.0           rustc --version
-bindgen (optional)     0.56.0           bindgen --version
+bindgen (optional)     0.65.1           bindgen --version
 GNU make               3.82             make --version
 bash                   4.2              bash --version
 binutils               2.25             ld -v

rust/Makefile

@@ -325,7 +325,7 @@ quiet_cmd_bindgen = BINDGEN $@
 	$(BINDGEN) $< $(bindgen_target_flags) \
 		--use-core --with-derive-default --ctypes-prefix core::ffi --no-layout-tests \
 		--no-debug '.*' \
-		--size_t-is-usize -o $@ -- $(bindgen_c_flags_final) -DMODULE \
+		-o $@ -- $(bindgen_c_flags_final) -DMODULE \
 		$(bindgen_target_cflags) $(bindgen_target_extra)
 
 $(obj)/bindings/bindings_generated.rs: private bindgen_target_flags = \
@@ -339,8 +339,8 @@ $(obj)/bindings/bindings_generated.rs: $(src)/bindings/bindings_helper.h \
 # given it is `libclang`; but for consistency, future Clang changes and/or
 # a potential future GCC backend for `bindgen`, we disable it too.
 $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_flags = \
-    --blacklist-type '.*' --whitelist-var '' \
-    --whitelist-function 'rust_helper_.*'
+    --blocklist-type '.*' --allowlist-var '' \
+    --allowlist-function 'rust_helper_.*'
 $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_cflags = \
     -I$(objtree)/$(obj) -Wno-missing-prototypes -Wno-missing-declarations
 $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ; \

rust/bindings/bindings_helper.h

@@ -36,6 +36,7 @@
 #include <linux/sysctl.h>
 #include <linux/uaccess.h>
 #include <linux/uio.h>
+#include <linux/mlx4/driver.h>
 
 /* `bindgen` gets confused at certain things. */
 const gfp_t BINDINGS_GFP_KERNEL = GFP_KERNEL;

rust/helpers.c

@@ -657,19 +657,18 @@ int rust_helper_fs_parse(struct fs_context *fc,
 EXPORT_SYMBOL_GPL(rust_helper_fs_parse);
 
 /*
- * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
- * as the Rust `usize` type, so we can use it in contexts where Rust
- * expects a `usize` like slice (array) indices. `usize` is defined to be
- * the same as C's `uintptr_t` type (can hold any pointer) but not
- * necessarily the same as `size_t` (can hold the size of any single
+ * `bindgen` binds the C `size_t` type the Rust `usize` type, so we can
+ * use it in contexts where Rust expects a `usize` like slice (array) indices.
+ * `usize` is defined to be the same as C's `uintptr_t` type (can hold any pointer)
+ * but not necessarily the same as `size_t` (can hold the size of any single
  * object). Most modern platforms use the same concrete integer type for
  * both of them, but in case we find ourselves on a platform where
  * that's not true, fail early instead of risking ABI or
  * integer-overflow issues.
  *
  * If your platform fails this assertion, it means that you are in
- * danger of integer-overflow bugs (even if you attempt to remove
- * `--size_t-is-usize`). It may be easiest to change the kernel ABI on
+ * danger of integer-overflow bugs (even if you attempt to add
+ * `--no-size_t-is-usize`). It may be easiest to change the kernel ABI on
  * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
  * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
  */

rust/kernel/lib.rs

@@ -76,6 +76,8 @@ pub mod task;
 pub mod workqueue;
 
 pub mod linked_list;
+#[cfg(CONFIG_MLX4_EN)]
+pub mod mlx4;
 mod raw_list;
 pub mod rbtree;
 pub mod unsafe_list;
@@ -257,7 +259,4 @@ fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
     pr_emerg!("{}\n", info);
     // SAFETY: FFI call.
     unsafe { bindings::BUG() };
-    // Bindgen currently does not recognize `__noreturn` so `BUG` returns `()`
-    // instead of `!`. See <https://github.com/rust-lang/rust-bindgen/issues/2094>.
-    loop {}
 }

rust/kernel/mlx4.rs

@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Infiniband mlx4 devices.
+//!
+
+use alloc::boxed::Box;
+use core::pin::Pin;
+use core::{marker, ptr};
+use macros::vtable;
+
+use crate::bindings;
+use crate::error::{code::*, Result};
+use crate::str::CStr;
+use crate::workqueue::{BoxedQueue, Queue};
+
+/// 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>,
+}
+
+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,
+            wq: Mlx4WorkQueue::new(),
+            cm_wq: CmWorkQueue::new(),
+            qp_wq: QpWorkQueue::new(),
+            mcg_wq: McgWorkQueue::new(),
+            phantom: marker::PhantomData,
+        }
+    }
+
+    /// 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(()) => {}
+            Err(e) => return Err(e),
+        }
+
+        match this.qp_wq.init() {
+            Ok(()) => {}
+            Err(e) => {
+                this.wq.clean();
+                return Err(e);
+            }
+        }
+
+        match this.cm_wq.init() {
+            Ok(()) => {}
+            Err(e) => {
+                this.wq.clean();
+                this.qp_wq.clean();
+                return Err(e);
+            }
+        }
+
+        match this.mcg_wq.init() {
+            Ok(()) => {}
+            Err(e) => {
+                this.wq.clean();
+                this.cm_wq.clean();
+                this.qp_wq.clean();
+                return Err(e);
+            }
+        }
+
+        // SAFETY: The adapter is compatible with the mlx4 register
+        unsafe {
+            bindings::mlx4_register_interface(Mlx4OperationTable::<T>::build());
+        }
+
+        this.registered = true;
+        Ok(())
+    }
+}
+
+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 {
+            self.mcg_wq.clean();
+            self.cm_wq.clean();
+            self.qp_wq.clean();
+            self.wq.clean();
+        }
+    }
+}
+
+/// 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),
+            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,
+        };
+    }
+
+    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,
+    ) {
+        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,
+    ) {
+        let _ = T::event();
+    }
+}
+
+/// Corresponds to the kernel's `struct mlx4_interface`.
+///
+/// You implement this trait whenever you would create a `struct mlx4_interface`.
+#[vtable]
+pub trait Mlx4Operation {
+    /// 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 {
+    wq: Option<BoxedQueue>,
+}
+
+impl Mlx4WorkQueue {
+    pub(crate) fn new() -> Self {
+        Self { wq: None }
+    }
+
+    pub(crate) fn init(&mut self) -> Result {
+        let wq_tmp = Queue::try_new(format_args!("mlx4_ib"), 655369, 1);
+        self.wq = match wq_tmp {
+            Ok(wq) => Some(wq),
+            Err(e) => return Err(e),
+        };
+
+        Ok(())
+    }
+
+    pub(crate) fn clean(&mut self) {
+        if self.wq.is_some() {
+            drop(self.wq.take().unwrap());
+        }
+    }
+}
+
+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

@@ -209,14 +209,14 @@ impl Queue {
     ///
     /// Callers should first consider using one of the existing ones (e.g. [`system`]) before
     /// deciding to create a new one.
-    pub fn try_new(name: fmt::Arguments<'_>) -> Result<BoxedQueue> {
+    pub fn try_new(name: fmt::Arguments<'_>, flags: u32, max_active: i32) -> Result<BoxedQueue> {
         // SAFETY: We use a format string that requires an `fmt::Arguments` pointer as the first
         // and only argument.
         let ptr = unsafe {
             bindings::alloc_workqueue(
                 c_str!("%pA").as_char_ptr(),
-                0,
-                0,
+                flags,
+                max_active,
                 &name as *const _ as *const core::ffi::c_void,
             )
         };
@@ -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`].
     ///