Commit f9f05dc5 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

block: Add bdrv_co_readv/writev emulation 



In order to be able to call bdrv_co_readv/writev for drivers that don't
implement the functions natively, add an emulation that uses the AIO functions
to implement them.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 68485420

block.c

+75 −8
Original line number Diff line number Diff line
@@ -64,6 +64,12 @@ static BlockDriverAIOCB *bdrv_co_aio_readv_em(BlockDriverState *bs, 
static BlockDriverAIOCB *bdrv_co_aio_writev_em(BlockDriverState *bs,

        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

        BlockDriverCompletionFunc *cb, void *opaque);

static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,

                                         int64_t sector_num, int nb_sectors,

                                         QEMUIOVector *iov);

static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,

                                         int64_t sector_num, int nb_sectors,

                                         QEMUIOVector *iov);



static QTAILQ_HEAD(, BlockDriverState) bdrv_states =

    QTAILQ_HEAD_INITIALIZER(bdrv_states);
@@ -182,7 +188,11 @@ void bdrv_register(BlockDriver *bdrv) 
        bdrv->bdrv_aio_writev = bdrv_co_aio_writev_em;

        bdrv->bdrv_read = bdrv_read_em;

        bdrv->bdrv_write = bdrv_write_em;

     } else if (!bdrv->bdrv_aio_readv) {

     } else {

        bdrv->bdrv_co_readv = bdrv_co_readv_em;

        bdrv->bdrv_co_writev = bdrv_co_writev_em;



        if (!bdrv->bdrv_aio_readv) {

            /* add AIO emulation layer */

            bdrv->bdrv_aio_readv = bdrv_aio_readv_em;

            bdrv->bdrv_aio_writev = bdrv_aio_writev_em;
@@ -191,6 +201,7 @@ void bdrv_register(BlockDriver *bdrv) 
            bdrv->bdrv_read = bdrv_read_em;

            bdrv->bdrv_write = bdrv_write_em;

        }

    }



    if (!bdrv->bdrv_aio_flush)

        bdrv->bdrv_aio_flush = bdrv_aio_flush_em;
@@ -2855,6 +2866,62 @@ void qemu_aio_release(void *p) 
    pool->free_aiocb = acb;

}



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

/* Coroutine block device emulation */



typedef struct CoroutineIOCompletion {

    Coroutine *coroutine;

    int ret;

} CoroutineIOCompletion;



static void bdrv_co_io_em_complete(void *opaque, int ret)

{

    CoroutineIOCompletion *co = opaque;



    co->ret = ret;

    qemu_coroutine_enter(co->coroutine, NULL);

}



static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num,

                                      int nb_sectors, QEMUIOVector *iov,

                                      bool is_write)

{

    CoroutineIOCompletion co = {

        .coroutine = qemu_coroutine_self(),

    };

    BlockDriverAIOCB *acb;



    if (is_write) {

        acb = bdrv_aio_writev(bs, sector_num, iov, nb_sectors,

                              bdrv_co_io_em_complete, &co);

    } else {

        acb = bdrv_aio_readv(bs, sector_num, iov, nb_sectors,

                             bdrv_co_io_em_complete, &co);

    }



    trace_bdrv_co_io(is_write, acb);

    if (!acb) {

        return -EIO;

    }

    qemu_coroutine_yield();



    return co.ret;

}



static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,

                                         int64_t sector_num, int nb_sectors,

                                         QEMUIOVector *iov)

{

    return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false);

}



static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,

                                         int64_t sector_num, int nb_sectors,

                                         QEMUIOVector *iov)

{

    return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true);

}



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

/* removable device support */

trace-events

+1 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ disable bdrv_aio_writev(void *bs, int64_t sector_num, int nb_sectors, void *opaq 
disable bdrv_set_locked(void *bs, int locked) "bs %p locked %d"

disable bdrv_co_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"

disable bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"

disable bdrv_co_io(int is_write, void *acb) "is_write %d acb %p"



# hw/virtio-blk.c

disable virtio_blk_req_complete(void *req, int status) "req %p status %d"