On Fri, May 26, 2017 at 10:22:06PM +0200, Kevin Wolf wrote:
> Most of the qed code is now synchronous and matches the coroutine model.
> One notable exception is the serialisation between requests which can
> still schedule a callback. Before we can replace this with coroutine
> locks, let's convert the driver's external interfaces to the coroutine
> versions.
>
> We need to be careful to handle both requests that call the completion
> callback directly from the calling coroutine (i.e. fully synchronous
> code) and requests that involve some callback, so that we need to yield
> and wait for the completion callback coming from outside the coroutine.
>
> Signed-off-by: Kevin Wolf <kw...@redhat.com>
> ---
> block/qed.c | 94
> +++++++++++++++++++++++++------------------------------------
> 1 file changed, 39 insertions(+), 55 deletions(-)
>
> diff --git a/block/qed.c b/block/qed.c
> index 6a83df2..29c3dc5 100644
> --- a/block/qed.c
> +++ b/block/qed.c
> @@ -1326,16 +1326,31 @@ static void qed_aio_next_io(QEDAIOCB *acb)
> }
> }
>
> -static BlockAIOCB *qed_aio_setup(BlockDriverState *bs,
> - int64_t sector_num,
> - QEMUIOVector *qiov, int nb_sectors,
> - BlockCompletionFunc *cb,
> - void *opaque, int flags)
> +typedef struct QEDRequestCo {
> + Coroutine *co;
> + bool done;
> + int ret;
> +} QEDRequestCo;
> +
> +static void coroutine_fn qed_co_request_cb(void *opaque, int ret)
> +{
> + QEDRequestCo *co = opaque;
> +
> + co->done = true;
> + co->ret = ret;
> + qemu_coroutine_enter_if_inactive(co->co);
> +}
> +
> +static int qed_co_request(BlockDriverState *bs, int64_t sector_num,
> + QEMUIOVector *qiov, int nb_sectors, int flags)
Missing coroutine_fn.
> {
> - QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque);
> + QEDRequestCo co = {
> + .co = qemu_coroutine_self(),
> + .done = false,
> + };
> + QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, qed_co_request_cb,
> &co);
>
> - trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors,
> - opaque, flags);
> + trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, &co, flags);
>
> acb->flags = flags;
> acb->qiov = qiov;
> @@ -1348,43 +1363,24 @@ static BlockAIOCB *qed_aio_setup(BlockDriverState *bs,
>
> /* Start request */
> qed_aio_start_io(acb);
> - return &acb->common;
> -}
>
> -static BlockAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs,
> - int64_t sector_num,
> - QEMUIOVector *qiov, int nb_sectors,
> - BlockCompletionFunc *cb,
> - void *opaque)
> -{
> - return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
> + if (!co.done) {
> + qemu_coroutine_yield();
> + }
> +
> + return co.ret;
> }
>
> -static BlockAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs,
> - int64_t sector_num,
> - QEMUIOVector *qiov, int nb_sectors,
> - BlockCompletionFunc *cb,
> - void *opaque)
> +static int bdrv_qed_co_readv(BlockDriverState *bs, int64_t sector_num,
> + int nb_sectors, QEMUIOVector *qiov)
Missing coroutine_fn. More below.
> {
> - return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb,
> - opaque, QED_AIOCB_WRITE);
> + return qed_co_request(bs, sector_num, qiov, nb_sectors, 0);
> }
>
> -typedef struct {
> - Coroutine *co;
> - int ret;
> - bool done;
> -} QEDWriteZeroesCB;
> -
> -static void coroutine_fn qed_co_pwrite_zeroes_cb(void *opaque, int ret)
> +static int bdrv_qed_co_writev(BlockDriverState *bs, int64_t sector_num,
> + int nb_sectors, QEMUIOVector *qiov)
> {
> - QEDWriteZeroesCB *cb = opaque;
> -
> - cb->done = true;
> - cb->ret = ret;
> - if (cb->co) {
> - aio_co_wake(cb->co);
> - }
> + return qed_co_request(bs, sector_num, qiov, nb_sectors, QED_AIOCB_WRITE);
> }
>
> static int coroutine_fn bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs,
> @@ -1392,9 +1388,7 @@ static int coroutine_fn
> bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs,
> int count,
> BdrvRequestFlags flags)
> {
> - BlockAIOCB *blockacb;
> BDRVQEDState *s = bs->opaque;
> - QEDWriteZeroesCB cb = { .done = false };
> QEMUIOVector qiov;
> struct iovec iov;
>
> @@ -1411,19 +1405,9 @@ static int coroutine_fn
> bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs,
> iov.iov_len = count;
>
> qemu_iovec_init_external(&qiov, &iov, 1);
> - blockacb = qed_aio_setup(bs, offset >> BDRV_SECTOR_BITS, &qiov,
> - count >> BDRV_SECTOR_BITS,
> - qed_co_pwrite_zeroes_cb, &cb,
> - QED_AIOCB_WRITE | QED_AIOCB_ZERO);
> - if (!blockacb) {
> - return -EIO;
> - }
> - if (!cb.done) {
> - cb.co = qemu_coroutine_self();
> - qemu_coroutine_yield();
> - }
> - assert(cb.done);
> - return cb.ret;
> + return qed_co_request(bs, offset >> BDRV_SECTOR_BITS, &qiov,
> + count >> BDRV_SECTOR_BITS,
> + QED_AIOCB_WRITE | QED_AIOCB_ZERO);
> }
>
> static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset, Error
> **errp)
> @@ -1619,8 +1603,8 @@ static BlockDriver bdrv_qed = {
> .bdrv_create = bdrv_qed_create,
> .bdrv_has_zero_init = bdrv_has_zero_init_1,
> .bdrv_co_get_block_status = bdrv_qed_co_get_block_status,
> - .bdrv_aio_readv = bdrv_qed_aio_readv,
> - .bdrv_aio_writev = bdrv_qed_aio_writev,
> + .bdrv_co_readv = bdrv_qed_co_readv,
> + .bdrv_co_writev = bdrv_qed_co_writev,
> .bdrv_co_pwrite_zeroes = bdrv_qed_co_pwrite_zeroes,
> .bdrv_truncate = bdrv_qed_truncate,
> .bdrv_getlength = bdrv_qed_getlength,
> --
> 1.8.3.1
>
>
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