[PATCH 2/2] thread-pool: use ThreadPool from the running thread

[Emanuele Giuseppe Esposito]

Remove usage of aio_context_acquire by always submitting work items
to the current thread's ThreadPool.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/file-posix.c    | 19 +++++++++----------
 block/file-win32.c    |  2 +-
 block/qcow2-threads.c |  2 +-
 util/thread-pool.c    |  6 +-----
 4 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 33f92f004a..15765453b3 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2053,11 +2053,10 @@ out:
     return result;
 }
 
-static int coroutine_fn raw_thread_pool_submit(BlockDriverState *bs,
-                                               ThreadPoolFunc func, void *arg)
+static int coroutine_fn raw_thread_pool_submit(ThreadPoolFunc func, void *arg)
 {
     /* @bs can be NULL, bdrv_get_aio_context() returns the main context then */
-    ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
+    ThreadPool *pool = aio_get_thread_pool(qemu_get_current_aio_context());
     return thread_pool_submit_co(pool, func, arg);
 }
 
@@ -2107,7 +2106,7 @@ static int coroutine_fn raw_co_prw(BlockDriverState *bs, 
uint64_t offset,
     };
 
     assert(qiov->size == bytes);
-    return raw_thread_pool_submit(bs, handle_aiocb_rw, &acb);
+    return raw_thread_pool_submit(handle_aiocb_rw, &acb);
 }
 
 static int coroutine_fn raw_co_preadv(BlockDriverState *bs, int64_t offset,
@@ -2182,7 +2181,7 @@ static int raw_co_flush_to_disk(BlockDriverState *bs)
         return luring_co_submit(bs, aio, s->fd, 0, NULL, QEMU_AIO_FLUSH);
     }
 #endif
-    return raw_thread_pool_submit(bs, handle_aiocb_flush, &acb);
+    return raw_thread_pool_submit(handle_aiocb_flush, &acb);
 }
 
 static void raw_aio_attach_aio_context(BlockDriverState *bs,
@@ -2244,7 +2243,7 @@ raw_regular_truncate(BlockDriverState *bs, int fd, 
int64_t offset,
         },
     };
 
-    return raw_thread_pool_submit(bs, handle_aiocb_truncate, &acb);
+    return raw_thread_pool_submit(handle_aiocb_truncate, &acb);
 }
 
 static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
@@ -2994,7 +2993,7 @@ raw_do_pdiscard(BlockDriverState *bs, int64_t offset, 
int64_t bytes,
         acb.aio_type |= QEMU_AIO_BLKDEV;
     }
 
-    ret = raw_thread_pool_submit(bs, handle_aiocb_discard, &acb);
+    ret = raw_thread_pool_submit(handle_aiocb_discard, &acb);
     raw_account_discard(s, bytes, ret);
     return ret;
 }
@@ -3069,7 +3068,7 @@ raw_do_pwrite_zeroes(BlockDriverState *bs, int64_t 
offset, int64_t bytes,
         handler = handle_aiocb_write_zeroes;
     }
 
-    return raw_thread_pool_submit(bs, handler, &acb);
+    return raw_thread_pool_submit(handler, &acb);
 }
 
 static int coroutine_fn raw_co_pwrite_zeroes(
@@ -3280,7 +3279,7 @@ static int coroutine_fn 
raw_co_copy_range_to(BlockDriverState *bs,
         },
     };
 
-    return raw_thread_pool_submit(bs, handle_aiocb_copy_range, &acb);
+    return raw_thread_pool_submit(handle_aiocb_copy_range, &acb);
 }
 
 BlockDriver bdrv_file = {
@@ -3626,7 +3625,7 @@ hdev_co_ioctl(BlockDriverState *bs, unsigned long int 
req, void *buf)
         },
     };
 
-    return raw_thread_pool_submit(bs, handle_aiocb_ioctl, &acb);
+    return raw_thread_pool_submit(handle_aiocb_ioctl, &acb);
 }
 #endif /* linux */
 
diff --git a/block/file-win32.c b/block/file-win32.c
index ec9d64d0e4..3d7f59a592 100644
--- a/block/file-win32.c
+++ b/block/file-win32.c
@@ -167,7 +167,7 @@ static BlockAIOCB *paio_submit(BlockDriverState *bs, HANDLE 
hfile,
     acb->aio_offset = offset;
 
     trace_file_paio_submit(acb, opaque, offset, count, type);
-    pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
+    pool = aio_get_thread_pool(qemu_get_current_aio_context());
     return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque);
 }
 
diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
index 1914baf456..9e370acbb3 100644
--- a/block/qcow2-threads.c
+++ b/block/qcow2-threads.c
@@ -42,7 +42,7 @@ qcow2_co_process(BlockDriverState *bs, ThreadPoolFunc *func, 
void *arg)
 {
     int ret;
     BDRVQcow2State *s = bs->opaque;
-    ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
+    ThreadPool *pool = aio_get_thread_pool(qemu_get_current_aio_context());
 
     qemu_co_mutex_lock(&s->lock);
     while (s->nb_threads >= QCOW2_MAX_THREADS) {
diff --git a/util/thread-pool.c b/util/thread-pool.c
index 31113b5860..74ce35f7a6 100644
--- a/util/thread-pool.c
+++ b/util/thread-pool.c
@@ -48,7 +48,7 @@ struct ThreadPoolElement {
     /* Access to this list is protected by lock.  */
     QTAILQ_ENTRY(ThreadPoolElement) reqs;
 
-    /* Access to this list is protected by the global mutex.  */
+    /* This list is only written by the thread pool's mother thread.  */
     QLIST_ENTRY(ThreadPoolElement) all;
 };
 
@@ -175,7 +175,6 @@ static void thread_pool_completion_bh(void *opaque)
     ThreadPool *pool = opaque;
     ThreadPoolElement *elem, *next;
 
-    aio_context_acquire(pool->ctx);
 restart:
     QLIST_FOREACH_SAFE(elem, &pool->head, all, next) {
         if (elem->state != THREAD_DONE) {
@@ -195,9 +194,7 @@ restart:
              */
             qemu_bh_schedule(pool->completion_bh);
 
-            aio_context_release(pool->ctx);
             elem->common.cb(elem->common.opaque, elem->ret);
-            aio_context_acquire(pool->ctx);
 
             /* We can safely cancel the completion_bh here regardless of 
someone
              * else having scheduled it meanwhile because we reenter the
@@ -211,7 +208,6 @@ restart:
             qemu_aio_unref(elem);
         }
     }
-    aio_context_release(pool->ctx);
 }
 
 static void thread_pool_cancel(BlockAIOCB *acb)
-- 
2.31.1