LXR qemu/block/aio

   1/*
   2 * Aio tasks loops
   3 *
   4 * Copyright (c) 2019 Virtuozzo International GmbH.
   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 "block/aio.h"
  27#include "block/aio_task.h"
  28
  29struct AioTaskPool {
  30    Coroutine *main_co;
  31    int status;
  32    int max_busy_tasks;
  33    int busy_tasks;
  34    bool waiting;
  35};
  36
  37static void coroutine_fn aio_task_co(void *opaque)
  38{
  39    AioTask *task = opaque;
  40    AioTaskPool *pool = task->pool;
  41
  42    assert(pool->busy_tasks < pool->max_busy_tasks);
  43    pool->busy_tasks++;
  44
  45    task->ret = task->func(task);
  46
  47    pool->busy_tasks--;
  48
  49    if (task->ret < 0 && pool->status == 0) {
  50        pool->status = task->ret;
  51    }
  52
  53    g_free(task);
  54
  55    if (pool->waiting) {
  56        pool->waiting = false;
  57        aio_co_wake(pool->main_co);
  58    }
  59}
  60
  61void coroutine_fn aio_task_pool_wait_one(AioTaskPool *pool)
  62{
  63    assert(pool->busy_tasks > 0);
  64    assert(qemu_coroutine_self() == pool->main_co);
  65
  66    pool->waiting = true;
  67    qemu_coroutine_yield();
  68
  69    assert(!pool->waiting);
  70    assert(pool->busy_tasks < pool->max_busy_tasks);
  71}
  72
  73void coroutine_fn aio_task_pool_wait_slot(AioTaskPool *pool)
  74{
  75    if (pool->busy_tasks < pool->max_busy_tasks) {
  76        return;
  77    }
  78
  79    aio_task_pool_wait_one(pool);
  80}
  81
  82void coroutine_fn aio_task_pool_wait_all(AioTaskPool *pool)
  83{
  84    while (pool->busy_tasks > 0) {
  85        aio_task_pool_wait_one(pool);
  86    }
  87}
  88
  89void coroutine_fn aio_task_pool_start_task(AioTaskPool *pool, AioTask *task)
  90{
  91    aio_task_pool_wait_slot(pool);
  92
  93    task->pool = pool;
  94    qemu_coroutine_enter(qemu_coroutine_create(aio_task_co, task));
  95}
  96
  97AioTaskPool *coroutine_fn aio_task_pool_new(int max_busy_tasks)
  98{
  99    AioTaskPool *pool = g_new0(AioTaskPool, 1);
 100
 101    assert(max_busy_tasks > 0);
 102
 103    pool->main_co = qemu_coroutine_self();
 104    pool->max_busy_tasks = max_busy_tasks;
 105
 106    return pool;
 107}
 108
 109void aio_task_pool_free(AioTaskPool *pool)
 110{
 111    g_free(pool);
 112}
 113
 114int aio_task_pool_status(AioTaskPool *pool)
 115{
 116    if (!pool) {
 117        return 0; /* Sugar for lazy allocation of aio pool */
 118    }
 119
 120    return pool->status;
 121}
 122
 123bool aio_task_pool_empty(AioTaskPool *pool)
 124{
 125    return pool->busy_tasks == 0;
 126}
 127