On 06/08/2016 08:10 AM, Kevin Wolf wrote: > In order to use the modern byte-based .bdrv_co_preadv/pwritev() > interface, this patch switches raw-posix to coroutine-based interfaces > as a first step. In terms of semantics and performance, it doesn't make > a difference with the existing code whether we go from a coroutine to a > callback-based interface already in block/io.c or only in linux-aio.c > > As there have been concerns in the past that this change may be a step > in the wrong direction with respect to a possible AIO fast path, the > old callback-based interface for linux-aio is left around and can be > reactivated when a fast path (e.g. directly from virtio-blk dataplane, > bypassing the whole block layer) is implemented. > > Signed-off-by: Kevin Wolf <[email protected]> > --- > block/linux-aio.c | 85 > +++++++++++++++++++++++++++++++++++++++++-------------- > block/raw-aio.h | 2 ++ > block/raw-posix.c | 59 ++++++++++++++++++-------------------- > 3 files changed, 92 insertions(+), 54 deletions(-) >
> +
> +int laio_submit_co(BlockDriverState *bs, LinuxAioState *s, int fd,
> + int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, int type)
> +{
> + off_t offset = sector_num * 512;
BDRV_SECTOR_SIZE instead of a magic number?
> + int ret;
> +
> + struct qemu_laiocb laiocb = {
> + .co = qemu_coroutine_self(),
> + .nbytes = nb_sectors * 512,
and again
> +
> +BlockAIOCB *laio_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
> + int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
> + BlockCompletionFunc *cb, void *opaque, int type)
> +{
> + struct qemu_laiocb *laiocb;
> + off_t offset = sector_num * 512;
> + int ret;
> +
> + laiocb = qemu_aio_get(&laio_aiocb_info, bs, cb, opaque);
> + laiocb->nbytes = nb_sectors * 512;
and again
> @@ -1345,14 +1344,26 @@ static BlockAIOCB *raw_aio_submit(BlockDriverState
> *bs,
> type |= QEMU_AIO_MISALIGNED;
> #ifdef CONFIG_LINUX_AIO
> } else if (s->use_aio) {
> - return laio_submit(bs, s->aio_ctx, s->fd, sector_num, qiov,
> - nb_sectors, cb, opaque, type);
> + return laio_submit_co(bs, s->aio_ctx, s->fd, sector_num, qiov,
> + nb_sectors, type);
Indentation is now off
> @@ -1957,8 +1952,8 @@ BlockDriver bdrv_file = {
> .bdrv_co_get_block_status = raw_co_get_block_status,
> .bdrv_co_pwrite_zeroes = raw_co_pwrite_zeroes,
>
> - .bdrv_aio_readv = raw_aio_readv,
> - .bdrv_aio_writev = raw_aio_writev,
> + .bdrv_co_readv = raw_co_readv,
> + .bdrv_co_writev = raw_co_writev,
> .bdrv_aio_flush = raw_aio_flush,
Why bother with indented alignment of '=' when none of the neighbors do?
Findings are minor enough, so up to you whether to fix them or just mark
this:
Reviewed-by: Eric Blake <[email protected]>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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