Commit 02c50efe authored by Fam Zheng's avatar Fam Zheng Committed by Stefan Hajnoczi
Browse files

block: Add bdrv_aio_cancel_async 



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: default avatarFam Zheng <famz@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent f197fe2b

block.c

+26 −1
Original line number Diff line number Diff line
@@ -4640,7 +4640,32 @@ int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs) 


void bdrv_aio_cancel(BlockDriverAIOCB *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);

    }

}



/**************************************************************/

include/block/aio.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

include/block/block.h

+1 −0
Original line number Diff line number Diff line
@@ -337,6 +337,7 @@ 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 */