rust: lock: introduce `SpinLock`

This is the `spinlock_t` lock backend and allows Rust code to use the
kernel spinlock idiomatically.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230419174426.132207-1-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/rust/helpers.c b/rust/helpers.c
index 86af099d2d66..446e3cfdb935 100644
--- a/rust/helpers.c
+++ b/rust/helpers.c
@@ -23,6 +23,7 @@
 #include <linux/err.h>
 #include <linux/refcount.h>
 #include <linux/mutex.h>
+#include <linux/spinlock.h>
 
 __noreturn void rust_helper_BUG(void)
 {
@@ -36,6 +37,29 @@ void rust_helper_mutex_lock(struct mutex *lock)
 }
 EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
 
+void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
+				  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+	__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
+#else
+	spin_lock_init(lock);
+#endif
+}
+EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
+
+void rust_helper_spin_lock(spinlock_t *lock)
+{
+	spin_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
+
+void rust_helper_spin_unlock(spinlock_t *lock)
+{
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
+
 refcount_t rust_helper_REFCOUNT_INIT(int n)
 {
 	return (refcount_t)REFCOUNT_INIT(n);