Squash commits for public release

kernel/include/libkern/rwlock.h

@@ -0,0 +1,74 @@
+#ifndef _KERNEL_LIBKERN_RWLOCK_H
+#define _KERNEL_LIBKERN_RWLOCK_H
+
+#include <libkern/atomic.h>
+#include <libkern/c_attrs.h>
+#include <libkern/kassert.h>
+#include <libkern/lock.h>
+#include <libkern/log.h>
+#include <libkern/types.h>
+
+struct rwlock {
+    int readers;
+    spinlock_t lock;
+#ifdef DEBUG_SPINLOCK
+
+#endif // DEBUG_SPINLOCK
+};
+typedef struct rwlock rwspinlock_t;
+
+static ALWAYS_INLINE void rwspinlock_init(rwspinlock_t* rwlock)
+{
+}
+
+static ALWAYS_INLINE void rwlock_r_acquire(rwspinlock_t* rwlock)
+{
+    spinlock_acquire(&rwlock->lock);
+    rwlock->readers++;
+    spinlock_release(&rwlock->lock);
+}
+
+static ALWAYS_INLINE void rwlock_r_release(rwspinlock_t* rwlock)
+{
+    spinlock_acquire(&rwlock->lock);
+    ASSERT(rwlock->readers >= 0);
+    rwlock->readers--;
+    spinlock_release(&rwlock->lock);
+}
+
+static ALWAYS_INLINE void rwlock_w_acquire(rwspinlock_t* rwlock)
+{
+    for (;;) {
+        spinlock_acquire(&rwlock->lock);
+        if (!rwlock->readers) {
+            return;
+        }
+        spinlock_release(&rwlock->lock);
+    }
+}
+
+static ALWAYS_INLINE void rwlock_w_release(rwspinlock_t* rwlock)
+{
+    spinlock_release(&rwlock->lock);
+}
+
+// #define DEBUG_SPINLOCK
+#ifdef DEBUG_SPINLOCK
+#define rwlock_r_acquire(x)                                    \
+    log("acquire r rwlock %s %s:%d ", #x, __FILE__, __LINE__); \
+    rwlock_r_acquire(x);
+
+#define rwlock_r_release(x)                                    \
+    log("release r rwlock %s %s:%d ", #x, __FILE__, __LINE__); \
+    rwlock_r_release(x);
+
+#define rwlock_w_acquire(x)                                    \
+    log("acquire w rwlock %s %s:%d ", #x, __FILE__, __LINE__); \
+    rwlock_w_acquire(x);
+
+#define rwlock_w_release(x)                                    \
+    log("release w rwlock %s %s:%d ", #x, __FILE__, __LINE__); \
+    rwlock_w_release(x);
+#endif
+
+#endif // _KERNEL_LIBKERN_RWLOCK_H