This is the async version of bdrv_aio_cancel, which doesn't block the
caller. It guarantees that the cb is called either before returning or
some time later.
bdrv_aio_cancel can base on bdrv_aio_cancel_async, later we can convert
all .io_cancel implementations to .io_cancel_async, and the aio_poll is
the common logic. In the end, .io_cancel can be dropped.
Signed-off-by: Fam Zheng <f...@redhat.com>
---
block.c | 27 ++++++++++++++++++++++++++-
include/block/aio.h | 2 ++
include/block/block.h | 1 +
3 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 78d68cb..2dfd1be 100644
--- a/block.c
+++ b/block.c
@@ -4634,7 +4634,32 @@ int bdrv_aio_multiwrite(BlockDriverState *bs,
BlockRequest *reqs, int num_reqs)
void bdrv_aio_cancel(BlockDriverAIOCB *acb)
{
- acb->aiocb_info->cancel(acb);
+ if (acb->aiocb_info->cancel) {
+ acb->aiocb_info->cancel(acb);
+ } else {
+ qemu_aio_ref(acb);
+ bdrv_aio_cancel_async(acb);
+ while (acb->refcnt > 1) {
+ if (acb->aiocb_info->get_aio_context) {
+ aio_poll(acb->aiocb_info->get_aio_context(acb), true);
+ } else if (acb->bs) {
+ aio_poll(bdrv_get_aio_context(acb->bs), true);
+ } else {
+ abort();
+ }
+ }
+ qemu_aio_release(acb);
+ }
+}
+
+/* Async version of aio cancel. The caller is not blocked if the acb implements
+ * cancel_async, otherwise we do nothing and let the request normally complete.
+ * In either case the completion callback must be called. */
+void bdrv_aio_cancel_async(BlockDriverAIOCB *acb)
+{
+ if (acb->aiocb_info->cancel_async) {
+ acb->aiocb_info->cancel_async(acb);
+ }
}
/**************************************************************/
diff --git a/include/block/aio.h b/include/block/aio.h
index 2626fc7..ad361e3 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -27,6 +27,8 @@ typedef void BlockDriverCompletionFunc(void *opaque, int ret);
typedef struct AIOCBInfo {
void (*cancel)(BlockDriverAIOCB *acb);
+ void (*cancel_async)(BlockDriverAIOCB *acb);
+ AioContext *(*get_aio_context)(BlockDriverAIOCB *acb);
size_t aiocb_size;
} AIOCBInfo;
diff --git a/include/block/block.h b/include/block/block.h
index 8f4ad16..35a2448 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -336,6 +336,7 @@ BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
BlockDriverCompletionFunc *cb, void
*opaque);
void bdrv_aio_cancel(BlockDriverAIOCB *acb);
+void bdrv_aio_cancel_async(BlockDriverAIOCB *acb);
typedef struct BlockRequest {
/* Fields to be filled by multiwrite caller */
--
2.1.0.27.g96db324
