Merge branch 'lukeshu/9p-fix-flush'

1 files changed, 65 insertions, 45 deletions

diff --git a/libcr_ipc/include/libcr_ipc/chan.h b/libcr_ipc/include/libcr_ipc/chan.h
index 5a87643..853b4ad 100644
--- a/libcr_ipc/include/libcr_ipc/chan.h
+++ b/libcr_ipc/include/libcr_ipc/chan.h
@@ -11,6 +11,7 @@
 #include <stddef.h>  /* for size_t */
 
 #include <libmisc/linkedlist.h> /* for DLIST_DECLARE() */
+#include <libmisc/private.h>
 
 /* base channels **************************************************************/
 
@@ -44,11 +45,9 @@
  *
  * void cr_chan_send(NAME##_t *ch, VAL_T val);
  */
-#define cr_chan_send(CH, VAL) do {                        \
-	cr_assert_in_coroutine();                         \
-	typeof((CH)->val_typ[0]) _val_lvalue = VAL;       \
-	_cr_chan_xfer(_CR_CHAN_SENDER, &(CH)->core,       \
-	              &_val_lvalue, sizeof(_val_lvalue)); \
+#define cr_chan_send(CH, VAL) do {                           \
+	typeof((CH)->val_typ[0]) _val_lvalue = VAL;          \
+	(void)cr_select_l(CR_SELECT_SEND(CH, &_val_lvalue)); \
 } while(0)
 
 /**
@@ -60,12 +59,10 @@
  *
  * VAL_T cr_chan_recv(NAME##_T ch);
  */
-#define cr_chan_recv(CH) ({                               \
-	cr_assert_in_coroutine();                         \
-	typeof((CH)->val_typ[0]) _val_lvalue;             \
-	_cr_chan_xfer(_CR_CHAN_RECVER, &(CH)->core,       \
-	              &_val_lvalue, sizeof(_val_lvalue)); \
-	_val_lvalue;                                      \
+#define cr_chan_recv(CH) ({                                  \
+	typeof((CH)->val_typ[0]) _val_lvalue;                \
+	(void)cr_select_l(CR_SELECT_RECV(CH, &_val_lvalue)); \
+	_val_lvalue;                                         \
 })
 
 /**
@@ -78,10 +75,10 @@
  *
  * bool cr_chan_can_send(NAME##_t *ch);
  */
-#define cr_chan_can_send(CH) ({                           \
-	cr_assert_in_coroutine();                         \
-	(bool)((CH)->core.waiters.front &&                \
-	       (CH)->core.waiter_typ == _CR_CHAN_RECVER); \
+#define cr_chan_can_send(CH) ({                                         \
+	cr_assert_in_coroutine();                                       \
+	(bool)((CH)->core.waiters.front &&                              \
+	       (CH)->core.waiters.front->val.op == _CR_SELECT_OP_RECV); \
 })
 
 /**
@@ -94,78 +91,101 @@
  *
  * bool cr_chan_can_recv(NAME##_t *ch);
  */
-#define cr_chan_can_recv(CH) ({                           \
-	cr_assert_in_coroutine();                         \
-	(bool)((CH)->core.waiters.front &&                \
-	       (CH)->core.waiter_typ == _CR_CHAN_SENDER); \
+#define cr_chan_can_recv(CH) ({                                         \
+	cr_assert_in_coroutine();                                       \
+	(bool)((CH)->core.waiters.front &&                              \
+	       (CH)->core.waiters.front->val.op == _CR_SELECT_OP_SEND); \
 })
 
+/**
+ * cr_chan_num_waiters(ch) returns the number of coroutines currently
+ * blocked on the channel.
+ *
+ * @runs_in coroutine
+ * @cr_pauses never
+ * @cr_yields never
+ *
+ * size_t cr_chan_num_waiters(NAME##_t *ch);
+ */
+#define cr_chan_num_waiters(CH) ({ \
+	cr_assert_in_coroutine();  \
+	((CH)->core.nwaiters);     \
+})
 
-enum _cr_chan_waiter_typ {
-	_CR_CHAN_SENDER,
-	_CR_CHAN_RECVER,
-};
-
-DLIST_DECLARE(_cr_chan_waiter_list);
-
+DLIST_DECLARE(_cr_select_arg_list);
 struct _cr_chan {
-	enum _cr_chan_waiter_typ        waiter_typ;
-	struct _cr_chan_waiter_list     waiters;
+	struct _cr_select_arg_list   waiters;
+	size_t                       nwaiters;
 };
 
-void _cr_chan_xfer(enum _cr_chan_waiter_typ self_typ, struct _cr_chan *ch, void *val_ptr, size_t val_size);
-
 /* cr_select arguments ********************************************************/
 
 /**
  * Do not populate cr_select_arg yourself; use the
  * CR_SELECT_{RECV,SEND,DEFAULT} macros.
  */
-struct cr_select_arg {
+struct _cr_select_waiter;
+struct _cr_select_arg {
 	enum {
 		_CR_SELECT_OP_RECV,
 		_CR_SELECT_OP_SEND,
 		_CR_SELECT_OP_DEFAULT,
-	}                        op;
-	struct _cr_chan         *ch;
-	void                    *val_ptr;
-	size_t                   val_siz;
+	}                                op;
+	struct _cr_chan                 *ch;
+	void                            *val_ptr;
+	size_t                           val_siz;
+	BEGIN_PRIVATE(LIBCR_IPC_CHAN_H);
+	struct _cr_select_waiter        *waiter;
+	END_PRIVATE(LIBCR_IPC_CHAN_H);
 };
+DLIST_DECLARE_NODE(_cr_select_arg_list, struct _cr_select_arg);
+#define cr_select_arg _cr_select_arg_list_node
 
-#define CR_SELECT_RECV(CH, VALP) ((struct cr_select_arg){                    \
+#define CR_SELECT_RECV(CH, VALP) ((struct cr_select_arg){ .val = {           \
 	.op      = _CR_SELECT_OP_RECV,                                       \
 	.ch      = &((CH)->core),                                            \
 	/* The _valp temporary variable is to get the compiler to check that \
 	 * the types are compatible.  */                                     \
 	.val_ptr = ({ typeof((CH)->val_typ[0]) *_valp = VALP; _valp; }),     \
 	.val_siz = sizeof((CH)->val_typ[0]),                                 \
-})
+}})
 
 /* BUG: It's bogus that CR_SELECT_SEND takes VALP instead of VAL, but
  * since we need an address, taking VAL would introduce uncomfortable
  * questions about where VAL sits on the stack.  */
-#define CR_SELECT_SEND(CH, VALP) ((struct cr_select_arg){                    \
+#define CR_SELECT_SEND(CH, VALP) ((struct cr_select_arg){ .val = {           \
 	.op      = _CR_SELECT_OP_SEND,                                       \
 	.ch      = &((CH)->core),                                            \
 	/* The _valp temporary variable is to get the compiler to check that \
 	 * the types are compatible.  */                                     \
 	.val_ptr = ({ typeof((CH)->val_typ[0]) *_valp = VALP; _valp; }),     \
 	.val_siz = sizeof((CH)->val_typ[0]),                                 \
-})
+}})
 
-#define CR_SELECT_DEFAULT ((struct cr_select_arg){ \
-	.op      = _CR_SELECT_OP_DEFAULT,          \
-})
+#define CR_SELECT_DEFAULT ((struct cr_select_arg){ .val = { \
+	.op      = _CR_SELECT_OP_DEFAULT,                   \
+}})
 
 /* cr_select_v(arg_cnt, arg_vec) **********************************************/
 
+/**
+ * @runs_in coroutine
+ * @cr_pauses maybe
+ * @cr_yields always
+ */
 size_t cr_select_v(size_t arg_cnt, struct cr_select_arg arg_vec[]);
 
 /* cr_select_l(arg1, arg2, arg3, ...) ******************************************/
 
-#define cr_select_l(...) ({                                              \
-	struct cr_select_arg _cr_select_args[] = { __VA_ARGS__ };        \
-	cr_select_v(sizeof(_cr_select_args)/sizeof(_cr_select_args[0])); \
+/**
+ * @runs_in coroutine
+ * @cr_pauses maybe
+ * @cr_yields always
+ */
+#define cr_select_l(...) ({                                             \
+	struct cr_select_arg _cr_select_args[] = { __VA_ARGS__ };       \
+	cr_select_v(sizeof(_cr_select_args)/sizeof(_cr_select_args[0]), \
+	            _cr_select_args);                                   \
 })
 
 #endif /* _LIBCR_IPC_CHAN_H_ */