Remove unneeded synchronizations in Chan

Everything was already guarded by `c.mutex`.

core/sync/chan/chan.odin

@@ -22,19 +22,17 @@ Raw_Chan :: struct {
 	allocator:       runtime.Allocator,
 	allocation_size: int,
 	msg_size:        u16,
-	closed:          b16, // atomic
+	closed:          b16, // guarded by `mutex`
 	mutex:           sync.Mutex,
 	r_cond:          sync.Cond,
 	w_cond:          sync.Cond,
-	r_waiting:       int,  // atomic
-	w_waiting:       int,  // atomic
+	r_waiting:       int,  // guarded by `mutex`
+	w_waiting:       int,  // guarded by `mutex`
 
 	// Buffered
 	queue: ^Raw_Queue,
 
 	// Unbuffered
-	r_mutex:         sync.Mutex,
-	w_mutex:         sync.Mutex,
 	unbuffered_data: rawptr,
 }
 
@@ -164,32 +162,30 @@ send_raw :: proc "contextless" (c: ^Raw_Chan, msg_in: rawptr) -> (ok: bool) {
 	}
 	if c.queue != nil { // buffered
 		sync.guard(&c.mutex)
-		for !sync.atomic_load(&c.closed) &&
-		    c.queue.len == c.queue.cap {
-			sync.atomic_add(&c.w_waiting, 1)
+		for !c.closed && c.queue.len == c.queue.cap {
+			c.w_waiting += 1
 			sync.wait(&c.w_cond, &c.mutex)
-			sync.atomic_sub(&c.w_waiting, 1)
+			c.w_waiting -= 1
 		}
 
-		if sync.atomic_load(&c.closed) {
+		if c.closed {
 			return false
 		}
 
 		ok = raw_queue_push(c.queue, msg_in)
-		if sync.atomic_load(&c.r_waiting) > 0 {
+		if c.r_waiting > 0 {
 			sync.signal(&c.r_cond)
 		}
 	} else if c.unbuffered_data != nil { // unbuffered
-		sync.guard(&c.w_mutex)
 		sync.guard(&c.mutex)
 
-		if sync.atomic_load(&c.closed) {
+		if c.closed {
 			return false
 		}
 
 		mem.copy(c.unbuffered_data, msg_in, int(c.msg_size))
-		sync.atomic_add(&c.w_waiting, 1)
-		if sync.atomic_load(&c.r_waiting) > 0 {
+		c.w_waiting += 1
+		if c.r_waiting > 0 {
 			sync.signal(&c.r_cond)
 		}
 		sync.wait(&c.w_cond, &c.mutex)
@@ -206,13 +202,13 @@ recv_raw :: proc "contextless" (c: ^Raw_Chan, msg_out: rawptr) -> (ok: bool) {
 	if c.queue != nil { // buffered
 		sync.guard(&c.mutex)
 		for c.queue.len == 0 {
-			if sync.atomic_load(&c.closed) {
+			if c.closed {
 				return
 			}
 
-			sync.atomic_add(&c.r_waiting, 1)
+			c.r_waiting += 1
 			sync.wait(&c.r_cond, &c.mutex)
-			sync.atomic_sub(&c.r_waiting, 1)
+			c.r_waiting -= 1
 		}
 
 		msg := raw_queue_pop(c.queue)
@@ -220,27 +216,26 @@ recv_raw :: proc "contextless" (c: ^Raw_Chan, msg_out: rawptr) -> (ok: bool) {
 			mem.copy(msg_out, msg, int(c.msg_size))
 		}
 
-		if sync.atomic_load(&c.w_waiting) > 0 {
+		if c.w_waiting > 0 {
 			sync.signal(&c.w_cond)
 		}
 		ok = true
 	} else if c.unbuffered_data != nil { // unbuffered
-		sync.guard(&c.r_mutex)
 		sync.guard(&c.mutex)
 
-		for !sync.atomic_load(&c.closed) &&
-		    sync.atomic_load(&c.w_waiting) == 0 {
-			sync.atomic_add(&c.r_waiting, 1)
+		for !c.closed &&
+			c.w_waiting == 0 {
+			c.r_waiting += 1
 			sync.wait(&c.r_cond, &c.mutex)
-			sync.atomic_sub(&c.r_waiting, 1)
+			c.r_waiting -= 1
 		}
 
-		if sync.atomic_load(&c.closed) {
+		if c.closed {
 			return
 		}
 
 		mem.copy(msg_out, c.unbuffered_data, int(c.msg_size))
-		sync.atomic_sub(&c.w_waiting, 1)
+		c.w_waiting -= 1
 
 		sync.signal(&c.w_cond)
 		ok = true
@@ -260,25 +255,24 @@ try_send_raw :: proc "contextless" (c: ^Raw_Chan, msg_in: rawptr) -> (ok: bool)
 			return false
 		}
 
-		if sync.atomic_load(&c.closed) {
+		if c.closed {
 			return false
 		}
 
 		ok = raw_queue_push(c.queue, msg_in)
-		if sync.atomic_load(&c.r_waiting) > 0 {
+		if c.r_waiting > 0 {
 			sync.signal(&c.r_cond)
 		}
 	} else if c.unbuffered_data != nil { // unbuffered
-		sync.guard(&c.w_mutex)
 		sync.guard(&c.mutex)
 
-		if sync.atomic_load(&c.closed) {
+		if c.closed {
 			return false
 		}
 
 		mem.copy(c.unbuffered_data, msg_in, int(c.msg_size))
-		sync.atomic_add(&c.w_waiting, 1)
-		if sync.atomic_load(&c.r_waiting) > 0 {
+		c.w_waiting += 1
+		if c.r_waiting > 0 {
 			sync.signal(&c.r_cond)
 		}
 		sync.wait(&c.w_cond, &c.mutex)
@@ -303,21 +297,19 @@ try_recv_raw :: proc "contextless" (c: ^Raw_Chan, msg_out: rawptr) -> bool {
 			mem.copy(msg_out, msg, int(c.msg_size))
 		}
 
-		if sync.atomic_load(&c.w_waiting) > 0 {
+		if c.w_waiting > 0 {
 			sync.signal(&c.w_cond)
 		}
 		return true
 	} else if c.unbuffered_data != nil { // unbuffered
-		sync.guard(&c.r_mutex)
 		sync.guard(&c.mutex)
 
-		if sync.atomic_load(&c.closed) ||
-		   sync.atomic_load(&c.w_waiting) == 0 {
+		if c.closed || c.w_waiting == 0 {
 			return false
 		}
 
 		mem.copy(msg_out, c.unbuffered_data, int(c.msg_size))
-		sync.atomic_sub(&c.w_waiting, 1)
+		c.w_waiting -= 1
 
 		sync.signal(&c.w_cond)
 		return true
@@ -360,10 +352,10 @@ close :: proc "contextless" (c: ^Raw_Chan) -> bool {
 		return false
 	}
 	sync.guard(&c.mutex)
-	if sync.atomic_load(&c.closed) {
+	if c.closed {
 		return false
 	}
-	sync.atomic_store(&c.closed, true)
+	c.closed = true
 	sync.broadcast(&c.r_cond)
 	sync.broadcast(&c.w_cond)
 	return true
@@ -375,7 +367,7 @@ is_closed :: proc "contextless" (c: ^Raw_Chan) -> bool {
 		return true
 	}
 	sync.guard(&c.mutex)
-	return bool(sync.atomic_load(&c.closed))
+	return bool(c.closed)
 }
 
 
@@ -434,7 +426,7 @@ can_recv :: proc "contextless" (c: ^Raw_Chan) -> bool {
 	if is_buffered(c) {
 		return c.queue.len > 0
 	}
-	return sync.atomic_load(&c.w_waiting) > 0
+	return c.w_waiting > 0
 }
 
 
@@ -444,7 +436,7 @@ can_send :: proc "contextless" (c: ^Raw_Chan) -> bool {
 	if is_buffered(c) {
 		return c.queue.len < c.queue.cap
 	}
-	return sync.atomic_load(&c.w_waiting) == 0
+	return c.w_waiting == 0
 }
 
 
@@ -493,4 +485,4 @@ select_raw :: proc "odin" (recvs: []^Raw_Chan, sends: []^Raw_Chan, send_msgs: []
 		ok = send_raw(sends[sel.idx], send_msgs[sel.idx])
 	}
 	return
-}
+}