server: Avoid using interlocked functions.

server/change.c

@@ -88,7 +88,7 @@ struct dir
     uid_t          uid;      /* file stat.st_uid */
     struct list    entry;    /* entry in global change notifications list */
     unsigned int   filter;   /* notification filter */
-    int            notified; /* SIGIO counter */
+    volatile int   notified; /* SIGIO counter */
     int            want_data; /* return change data */
     int            subtree;  /* do we want to watch subdirectories? */
     struct list    change_records;   /* data for the change */
@@ -307,7 +307,7 @@ void do_change_notify( int unix_fd )
     LIST_FOR_EACH_ENTRY( dir, &change_list, struct dir, entry )
     {
         if (get_unix_fd( dir->fd ) != unix_fd) continue;
-        interlocked_xchg_add( &dir->notified, 1 );
+        dir->notified = 1;
         break;
     }
 }
@@ -319,8 +319,9 @@ void sigio_callback(void)
 
     LIST_FOR_EACH_ENTRY( dir, &change_list, struct dir, entry )
     {
-        if (interlocked_xchg( &dir->notified, 0 ))
-            fd_async_wake_up( dir->fd, ASYNC_TYPE_WAIT, STATUS_ALERTED );
+        if (!dir->notified) continue;
+        dir->notified = 0;
+        fd_async_wake_up( dir->fd, ASYNC_TYPE_WAIT, STATUS_ALERTED );
     }
 }