Merge pull request #217 from wedsonaf/exports

Expose `signal_pending` and `cond_resched` to drivers.

Author: ojeda

rust/helpers.c

@@ -81,6 +81,12 @@ void rust_helper_kunmap(struct page *page)
 }
 EXPORT_SYMBOL_GPL(rust_helper_kunmap);
 
+int rust_helper_cond_resched(void)
+{
+	return cond_resched();
+}
+EXPORT_SYMBOL_GPL(rust_helper_cond_resched);
+
 #if !defined(CONFIG_ARM)
 // See https://github.com/rust-lang/rust-bindgen/issues/1671
 static_assert(__builtin_types_compatible_p(size_t, uintptr_t),

rust/kernel/sync/condvar.rs

@@ -6,12 +6,11 @@
 //! variable.
 
 use super::{Guard, Lock, NeedsLockClass};
-use crate::{bindings, c_types, CStr};
+use crate::{bindings, CStr};
 use core::{cell::UnsafeCell, marker::PhantomPinned, mem::MaybeUninit, pin::Pin};
 
 extern "C" {
     fn rust_helper_init_wait(wq: *mut bindings::wait_queue_entry);
-    fn rust_helper_signal_pending() -> c_types::c_int;
 }
 
 /// Safely initialises a [`CondVar`] with the given name, generating a new lock class.
@@ -92,8 +91,7 @@ impl CondVar {
         // SAFETY: Both `wait` and `wait_list` point to valid memory.
         unsafe { bindings::finish_wait(self.wait_list.get(), wait.as_mut_ptr()) };
 
-        // SAFETY: No arguments, just checks `current` for pending signals.
-        unsafe { rust_helper_signal_pending() != 0 }
+        super::signal_pending()
     }
 
     /// Calls the kernel function to notify the appropriate number of threads with the given flags.

rust/kernel/sync/mod.rs

@@ -17,7 +17,7 @@
 //! }
 //! ```
 
-use crate::{bindings, CStr};
+use crate::{bindings, c_types, CStr};
 use core::pin::Pin;
 
 mod arc;
@@ -34,6 +34,11 @@ pub use locked_by::LockedBy;
 pub use mutex::Mutex;
 pub use spinlock::SpinLock;
 
+extern "C" {
+    fn rust_helper_signal_pending() -> c_types::c_int;
+    fn rust_helper_cond_resched() -> c_types::c_int;
+}
+
 /// Safely initialises an object that has an `init` function that takes a name and a lock class as
 /// arguments, examples of these are [`Mutex`] and [`SpinLock`]. Each of them also provides a more
 /// specialised name that uses this macro.
@@ -66,3 +71,15 @@ pub trait NeedsLockClass {
     /// `key` must point to a valid memory location as it will be used by the kernel.
     unsafe fn init(self: Pin<&Self>, name: CStr<'static>, key: *mut bindings::lock_class_key);
 }
+
+/// Determines if a signal is pending on the current process.
+pub fn signal_pending() -> bool {
+    // SAFETY: No arguments, just checks `current` for pending signals.
+    unsafe { rust_helper_signal_pending() != 0 }
+}
+
+/// Reschedules the caller's task if needed.
+pub fn cond_resched() -> bool {
+    // SAFETY: No arguments, reschedules `current` if needed.
+    unsafe { rust_helper_cond_resched() != 0 }
+}