qemu/block/aio_task.c

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/*
* Aio tasks loops
*
* Copyright (c) 2019 Virtuozzo International GmbH.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "block/aio.h"
#include "block/aio_task.h"
struct AioTaskPool {
Coroutine *main_co;
int status;
int max_busy_tasks;
int busy_tasks;
bool waiting;
};
static void coroutine_fn aio_task_co(void *opaque)
{
AioTask *task = opaque;
AioTaskPool *pool = task->pool;
assert(pool->busy_tasks < pool->max_busy_tasks);
pool->busy_tasks++;
task->ret = task->func(task);
pool->busy_tasks--;
if (task->ret < 0 && pool->status == 0) {
pool->status = task->ret;
}
g_free(task);
if (pool->waiting) {
pool->waiting = false;
aio_co_wake(pool->main_co);
}
}
void coroutine_fn aio_task_pool_wait_one(AioTaskPool *pool)
{
assert(pool->busy_tasks > 0);
assert(qemu_coroutine_self() == pool->main_co);
pool->waiting = true;
qemu_coroutine_yield();
assert(!pool->waiting);
assert(pool->busy_tasks < pool->max_busy_tasks);
}
void coroutine_fn aio_task_pool_wait_slot(AioTaskPool *pool)
{
if (pool->busy_tasks < pool->max_busy_tasks) {
return;
}
aio_task_pool_wait_one(pool);
}
void coroutine_fn aio_task_pool_wait_all(AioTaskPool *pool)
{
while (pool->busy_tasks > 0) {
aio_task_pool_wait_one(pool);
}
}
void coroutine_fn aio_task_pool_start_task(AioTaskPool *pool, AioTask *task)
{
aio_task_pool_wait_slot(pool);
task->pool = pool;
qemu_coroutine_enter(qemu_coroutine_create(aio_task_co, task));
}
AioTaskPool *coroutine_fn aio_task_pool_new(int max_busy_tasks)
{
AioTaskPool *pool = g_new0(AioTaskPool, 1);
assert(max_busy_tasks > 0);
pool->main_co = qemu_coroutine_self();
pool->max_busy_tasks = max_busy_tasks;
return pool;
}
void aio_task_pool_free(AioTaskPool *pool)
{
g_free(pool);
}
int aio_task_pool_status(AioTaskPool *pool)
{
if (!pool) {
return 0; /* Sugar for lazy allocation of aio pool */
}
return pool->status;
}
bool aio_task_pool_empty(AioTaskPool *pool)
{
return pool->busy_tasks == 0;
}