More lwIP sys_mbox implementation.

18399524 · Silas Boyd-Wickizer · a6a56669 · 18399524 · 18399524
--- a/net/arch/sys_arch.h
+++ b/net/arch/sys_arch.h
@@ -12,15 +12,16 @@ typedef struct sys_mbox {
 #define MBOXSLOTS 32
  struct spinlock s;
  struct condvar c;
-  int head;
-  int tail;
+  volatile int invalid;
+  volatile int head;
+  volatile int tail;
  void *msg[MBOXSLOTS];
 } sys_mbox_t;

 typedef struct sys_sem {
  struct spinlock s;
  struct condvar c;
-  u8 count;
+  volatile u8 count;
 } sys_sem_t;

 #define SYS_ARCH_NOWAIT  0xfffffffe

--- a/net/sys_arch.c
+++ b/net/sys_arch.c
@@ -26,6 +26,7 @@ sys_mbox_new(sys_mbox_t *mbox, int size)
  }
  mbox->head = 0;
  mbox->tail = 0;
+  mbox->invalid = 0;
  initlock(&mbox->s, "lwIP mbox");
  initcondvar(&mbox->c, "lwIP mbox");

@@ -35,7 +36,7 @@ sys_mbox_new(sys_mbox_t *mbox, int size)
 void
 sys_mbox_set_invalid(sys_mbox_t *mbox)
 {
-  DIE;
+  mbox->invalid = 1;
 }

 err_t
@@ -47,13 +48,18 @@ sys_mbox_trypost(sys_mbox_t *mbox, void *msg)
 int
 sys_mbox_valid(sys_mbox_t *mbox)
 {
-  DIE;
+  return !mbox->invalid;
 }

 void
 sys_mbox_post(sys_mbox_t *mbox, void *msg)
 {
-  DIE;
+  acquire(&mbox->s);
+  while (mbox->head - mbox->tail == MBOXSLOTS)
+    cv_sleep(&mbox->c, &mbox->s);
+  mbox->msg[mbox->head % MBOXSLOTS] = msg;
+  mbox->head++;
+  release(&mbox->s);
 }

 void