[PATCH 1/2] linux-aio: use LinuxAioState from the running thread

[Emanuele Giuseppe Esposito]

From: Paolo Bonzini <pbonzini@redhat.com>

Remove usage of aio_context_acquire by always submitting asynchronous
AIO to the current thread's LinuxAioState.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/file-posix.c  |  3 ++-
 block/linux-aio.c   | 13 ++++++-------
 include/block/aio.h |  4 ----
 3 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 48cd096624..33f92f004a 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2086,7 +2086,8 @@ static int coroutine_fn raw_co_prw(BlockDriverState *bs, 
uint64_t offset,
 #endif
 #ifdef CONFIG_LINUX_AIO
     } else if (s->use_linux_aio) {
-        LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
+        AioContext *ctx = qemu_get_current_aio_context();
+        LinuxAioState *aio = aio_get_linux_aio(ctx);
         assert(qiov->size == bytes);
         return laio_co_submit(bs, aio, s->fd, offset, qiov, type,
                               s->aio_max_batch);
diff --git a/block/linux-aio.c b/block/linux-aio.c
index 4c423fcccf..1d3cc767d1 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -16,6 +16,9 @@
 #include "qemu/coroutine.h"
 #include "qapi/error.h"
 
+/* Only used for assertions.  */
+#include "qemu/coroutine_int.h"
+
 #include <libaio.h>
 
 /*
@@ -56,10 +59,8 @@ struct LinuxAioState {
     io_context_t ctx;
     EventNotifier e;
 
-    /* io queue for submit at batch.  Protected by AioContext lock. */
+    /* All data is only used in one I/O thread.  */
     LaioQueue io_q;
-
-    /* I/O completion processing.  Only runs in I/O thread.  */
     QEMUBH *completion_bh;
     int event_idx;
     int event_max;
@@ -102,9 +103,8 @@ static void qemu_laio_process_completion(struct qemu_laiocb 
*laiocb)
      * later.  Coroutines cannot be entered recursively so avoid doing
      * that!
      */
-    if (!qemu_coroutine_entered(laiocb->co)) {
-        aio_co_wake(laiocb->co);
-    }
+    assert(laiocb->co->ctx == laiocb->ctx->aio_context);
+    qemu_coroutine_enter_if_inactive(laiocb->co);
 }
 
 /**
@@ -238,7 +238,6 @@ static void 
qemu_laio_process_completions_and_submit(LinuxAioState *s)
     if (!s->io_q.plugged && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
         ioq_submit(s);
     }
-    aio_context_release(s->aio_context);
 }
 
 static void qemu_laio_completion_bh(void *opaque)
diff --git a/include/block/aio.h b/include/block/aio.h
index d128558f1d..8bb5eea4a9 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -200,10 +200,6 @@ struct AioContext {
     struct ThreadPool *thread_pool;
 
 #ifdef CONFIG_LINUX_AIO
-    /*
-     * State for native Linux AIO.  Uses aio_context_acquire/release for
-     * locking.
-     */
     struct LinuxAioState *linux_aio;
 #endif
 #ifdef CONFIG_LINUX_IO_URING
-- 
2.31.1