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Re: [Qemu-devel] [PATCH] block: document semanatics of bdrv_co_preadv|pw
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev |
Date: |
Fri, 4 Aug 2017 15:06:30 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
On Fri, Aug 04, 2017 at 04:02:10PM +0200, Kevin Wolf wrote:
> Am 04.08.2017 um 12:50 hat Daniel P. Berrange geschrieben:
> > Signed-off-by: Daniel P. Berrange <address@hidden>
> > ---
> > include/block/block_int.h | 29 +++++++++++++++++++++++++++++
> > 1 file changed, 29 insertions(+)
> >
> > diff --git a/include/block/block_int.h b/include/block/block_int.h
> > index d4f4ea7584..deb81a58bd 100644
> > --- a/include/block/block_int.h
> > +++ b/include/block/block_int.h
> > @@ -147,12 +147,41 @@ struct BlockDriver {
> >
> > int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
> > int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
> > +
> > + /**
> > + * @offset: position in bytes to read at
> > + * @bytes: number of bytes to read
> > + * @qiov: the buffers to fill with read data
> > + *
> > + * @offset and @bytes will be a multiple of 'request_alignment',
> > + * but the length of individual @qiov elements does not have to
> > + * be a multiple.
> > + *
> > + * @bytes may be less than the total sizeof @iov, and will be
> > + * no larger than 'max_transfer'.
>
> Really? We are asserting that they match in bdrv_aligned_preadv():
>
> assert(!qiov || bytes == qiov->size);
Hmm, why do we pass @bytes at all then ? If they're always the same,
how about deleting it and just letting everyone read qiov->size
directly.
> Also, s/sizeof @iov/size of @qiov/
>
> > + *
> > + * The buffer in @qiov may point directly to guest memory.
> > + */
> > int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs,
> > uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
> > int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
> > int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
> > int coroutine_fn (*bdrv_co_writev_flags)(BlockDriverState *bs,
> > int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags);
> > + /**
> > + * @offset: position in bytes to write at
> > + * @bytes: number of bytes to write
> > + * @qiov: the buffers containing data to write
> > + *
> > + * @offset and @bytes will be a multiple of 'request_alignment',
> > + * but the length of individual @qiov elements does not have to
> > + * be a multiple.
> > + *
> > + * @bytes may be less than the total sizeof @iov, and will be
> > + * no larger than 'max_transfer'.
>
> The same assertion exists in bdrv_aligned_pwritev() (and the same typo
> in your comment).
>
> > + * The buffer in @qiov may point directly to guest memory.
> > + */
> > int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs,
> > uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags);
>
> Kevin
Regards,
Daniel
--
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- [Qemu-devel] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Daniel P. Berrange, 2017/08/04
- Re: [Qemu-devel] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Stefan Hajnoczi, 2017/08/04
- Re: [Qemu-devel] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Kevin Wolf, 2017/08/04
- Re: [Qemu-devel] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev,
Daniel P. Berrange <=
- Re: [Qemu-devel] [Qemu-block] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Eric Blake, 2017/08/04
- Re: [Qemu-devel] [Qemu-block] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Daniel P. Berrange, 2017/08/04
- Re: [Qemu-devel] [Qemu-block] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Fam Zheng, 2017/08/07
- Re: [Qemu-devel] [Qemu-block] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Daniel P. Berrange, 2017/08/08
- Re: [Qemu-devel] [Qemu-block] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Eric Blake, 2017/08/08
Re: [Qemu-devel] [Qemu-block] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev, Eric Blake, 2017/08/04