util/aio-wait.c

   1 /*
   2  * AioContext wait support
   3  *
   4  * Copyright (C) 2018 Red Hat, Inc.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "qemu/osdep.h"
  26 #include "qemu/main-loop.h"
  27 #include "block/aio-wait.h"
  28
  29 static void dummy_bh_cb(void *opaque)
  30 {
  31     /* The point is to make AIO_WAIT_WHILE()'s aio_poll() return */
  32 }
  33
  34 void aio_wait_kick(AioWait *wait)
  35 {
  36     /* The barrier (or an atomic op) is in the caller.  */
  37     if (atomic_read(&wait->need_kick)) {
  38         aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL);
  39     }
  40 }