[PATCH v2 3/3] linux-aio: add `dev_max_batch` parameter to laio_io_unplug()

[Stefano Garzarella]

Between the submission of a request and the unplug, other devices
with larger limits may have been queued new requests without flushing
the batch.

Using the new `dev_max_batch` parameter, laio_io_unplug() can check
if the batch exceeds the device limit to flush the current batch.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 include/block/raw-aio.h | 3 ++-
 block/file-posix.c      | 2 +-
 block/linux-aio.c       | 8 +++++---
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h
index ebd042fa27..21fc10c4c9 100644
--- a/include/block/raw-aio.h
+++ b/include/block/raw-aio.h
@@ -56,7 +56,8 @@ int coroutine_fn laio_co_submit(BlockDriverState *bs, 
LinuxAioState *s, int fd,
 void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context);
 void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context);
 void laio_io_plug(BlockDriverState *bs, LinuxAioState *s);
-void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s);
+void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s,
+                    uint64_t dev_max_batch);
 #endif
 /* io_uring.c - Linux io_uring implementation */
 #ifdef CONFIG_LINUX_IO_URING
diff --git a/block/file-posix.c b/block/file-posix.c
index baf4197e88..966eab8d0b 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2125,7 +2125,7 @@ static void raw_aio_unplug(BlockDriverState *bs)
 #ifdef CONFIG_LINUX_AIO
     if (s->use_linux_aio) {
         LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
-        laio_io_unplug(bs, aio);
+        laio_io_unplug(bs, aio, s->aio_max_batch);
     }
 #endif
 #ifdef CONFIG_LINUX_IO_URING
diff --git a/block/linux-aio.c b/block/linux-aio.c
index 88b44fee72..f53ae72e21 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -356,11 +356,13 @@ void laio_io_plug(BlockDriverState *bs, LinuxAioState *s)
     s->io_q.plugged++;
 }
 
-void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s)
+void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s,
+                    uint64_t dev_max_batch)
 {
     assert(s->io_q.plugged);
-    if (--s->io_q.plugged == 0 &&
-        !s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
+    if (s->io_q.in_queue >= laio_max_batch(s, dev_max_batch) ||
+        (--s->io_q.plugged == 0 &&
+         !s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending))) {
         ioq_submit(s);
     }
 }
-- 
2.31.1