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Re: [Qemu-devel] [PATCH 4/6] block: switch bdrv_aio_readv() to coroutine
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH 4/6] block: switch bdrv_aio_readv() to coroutines |
Date: |
Wed, 12 Oct 2011 15:07:56 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:7.0) Gecko/20110927 Thunderbird/7.0 |
Am 05.10.2011 18:17, schrieb Stefan Hajnoczi:
> More sync, aio, and coroutine unification. Make bdrv_aio_readv() go
> through coroutine request processing.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> block.c | 48 +++++++++++++++++++++++++++++++++++-------------
> 1 files changed, 35 insertions(+), 13 deletions(-)
>
> diff --git a/block.c b/block.c
> index 90c29db..b83e911 100644
> --- a/block.c
> +++ b/block.c
> @@ -78,6 +78,15 @@ static int coroutine_fn bdrv_co_do_readv(BlockDriverState
> *bs,
> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
> static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
> int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
> +static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
> + int64_t sector_num,
> + QEMUIOVector *qiov,
> + int nb_sectors,
> + BlockDriverCompletionFunc *cb,
> + void *opaque,
> + bool is_write,
> + CoroutineEntry *entry);
> +static void coroutine_fn bdrv_co_do_rw(void *opaque);
>
> static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
> QTAILQ_HEAD_INITIALIZER(bdrv_states);
> @@ -2346,17 +2355,10 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState
> *bs, int64_t sector_num,
> QEMUIOVector *qiov, int nb_sectors,
> BlockDriverCompletionFunc *cb, void *opaque)
> {
> - BlockDriver *drv = bs->drv;
> -
> trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque);
>
> - if (!drv)
> - return NULL;
> - if (bdrv_check_request(bs, sector_num, nb_sectors))
> - return NULL;
> -
> - return drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors,
> - cb, opaque);
> + return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors,
> + cb, opaque, false, bdrv_co_do_rw);
> }
>
> typedef struct BlockCompleteData {
> @@ -2803,6 +2805,7 @@ static void bdrv_co_rw_bh(void *opaque)
> qemu_aio_release(acb);
> }
>
> +/* Invoke .bdrv_co_readv/.bdrv_co_writev */
> static void coroutine_fn bdrv_co_rw(void *opaque)
> {
> BlockDriverAIOCBCoroutine *acb = opaque;
> @@ -2820,13 +2823,32 @@ static void coroutine_fn bdrv_co_rw(void *opaque)
> qemu_bh_schedule(acb->bh);
> }
>
> +/* Invoke bdrv_co_do_readv/bdrv_co_do_writev */
> +static void coroutine_fn bdrv_co_do_rw(void *opaque)
> +{
> + BlockDriverAIOCBCoroutine *acb = opaque;
> + BlockDriverState *bs = acb->common.bs;
> +
> + if (!acb->is_write) {
> + acb->req.error = bdrv_co_do_readv(bs, acb->req.sector,
> + acb->req.nb_sectors, acb->req.qiov);
> + } else {
> + acb->req.error = bdrv_co_do_writev(bs, acb->req.sector,
> + acb->req.nb_sectors, acb->req.qiov);
> + }
> +
> + acb->bh = qemu_bh_new(bdrv_co_rw_bh, acb);
> + qemu_bh_schedule(acb->bh);
> +}
The difference between the existing bdrv_co_rw and the new bdrv_co_do_rw
is that the former directly calls drv->... whereas the latter does some
checks first.
I think you could just switch bdrv_co_rw to do the checks. If I'm not
mistaken, the other path is dead code anyway after this change.
Actually, it looks like this series leaves quite a bit of dead code
behind, but I need to apply all patches and check the result to be sure.
Kevin
- [Qemu-devel] [PATCH 0/6] block: do request processing in a coroutine, Stefan Hajnoczi, 2011/10/05
- [Qemu-devel] [PATCH 2/6] block: split out bdrv_co_do_readv() and bdrv_co_do_writev(), Stefan Hajnoczi, 2011/10/05
- [Qemu-devel] [PATCH 5/6] block: mark blocks dirty on coroutine write completion, Stefan Hajnoczi, 2011/10/05
- [Qemu-devel] [PATCH 6/6] block: switch bdrv_aio_writev() to coroutines, Stefan Hajnoczi, 2011/10/05
- [Qemu-devel] [PATCH 1/6] block: directly invoke .bdrv_aio_*() in bdrv_co_io_em(), Stefan Hajnoczi, 2011/10/05