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Re: [PATCH v2 10/29] io: Add generic pwritev/preadv interface
From: |
Daniel P . Berrangé |
Subject: |
Re: [PATCH v2 10/29] io: Add generic pwritev/preadv interface |
Date: |
Tue, 24 Oct 2023 09:18:52 +0100 |
User-agent: |
Mutt/2.2.9 (2022-11-12) |
On Mon, Oct 23, 2023 at 05:35:49PM -0300, Fabiano Rosas wrote:
> From: Nikolay Borisov <nborisov@suse.com>
>
> Introduce basic pwritev/preadv support in the generic channel layer.
> Specific implementation will follow for the file channel as this is
> required in order to support migration streams with fixed location of
> each ram page.
>
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> Signed-off-by: Fabiano Rosas <farosas@suse.de>
> ---
> include/io/channel.h | 82 ++++++++++++++++++++++++++++++++++++++++++++
> io/channel.c | 58 +++++++++++++++++++++++++++++++
> 2 files changed, 140 insertions(+)
>
> diff --git a/include/io/channel.h b/include/io/channel.h
> index fcb19fd672..a8181d576a 100644
> --- a/include/io/channel.h
> +++ b/include/io/channel.h
> @@ -131,6 +131,16 @@ struct QIOChannelClass {
> Error **errp);
>
> /* Optional callbacks */
> + ssize_t (*io_pwritev)(QIOChannel *ioc,
> + const struct iovec *iov,
> + size_t niov,
> + off_t offset,
> + Error **errp);
> + ssize_t (*io_preadv)(QIOChannel *ioc,
> + const struct iovec *iov,
> + size_t niov,
> + off_t offset,
> + Error **errp);
> int (*io_shutdown)(QIOChannel *ioc,
> QIOChannelShutdown how,
> Error **errp);
> @@ -529,6 +539,78 @@ void qio_channel_set_follow_coroutine_ctx(QIOChannel
> *ioc, bool enabled);
> int qio_channel_close(QIOChannel *ioc,
> Error **errp);
>
> +/**
> + * qio_channel_pwritev_full
> + * @ioc: the channel object
> + * @iov: the array of memory regions to write data from
> + * @niov: the length of the @iov array
> + * @offset: offset in the channel where writes should begin
> + * @errp: pointer to a NULL-initialized error object
> + *
> + * Not all implementations will support this facility, so may report
> + * an error. To avoid errors, the caller may check for the feature
> + * flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method.
> + *
> + * Behaves as qio_channel_writev_full, apart from not supporting
> + * sending of file handles as well as beginning the write at the
> + * passed @offset
> + *
> + */
> +ssize_t qio_channel_pwritev_full(QIOChannel *ioc, const struct iovec *iov,
> + size_t niov, off_t offset, Error **errp);
In terms of naming this should be just "_pwritev".
We don't support FD passing, so the "_full" suffix is not
appropriate
> +
> +/**
> + * qio_channel_pwritev
> + * @ioc: the channel object
> + * @buf: the memory region to write data into
> + * @buflen: the number of bytes to @buf
> + * @offset: offset in the channel where writes should begin
> + * @errp: pointer to a NULL-initialized error object
> + *
> + * Not all implementations will support this facility, so may report
> + * an error. To avoid errors, the caller may check for the feature
> + * flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method.
> + *
> + */
> +ssize_t qio_channel_pwritev(QIOChannel *ioc, char *buf, size_t buflen,
> + off_t offset, Error **errp);
This isn't passing a vector of buffers, so it should be just
"pwrite", not "pwritev".
> +
> +/**
> + * qio_channel_preadv_full
> + * @ioc: the channel object
> + * @iov: the array of memory regions to read data into
> + * @niov: the length of the @iov array
> + * @offset: offset in the channel where writes should begin
> + * @errp: pointer to a NULL-initialized error object
> + *
> + * Not all implementations will support this facility, so may report
> + * an error. To avoid errors, the caller may check for the feature
> + * flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method.
> + *
> + * Behaves as qio_channel_readv_full, apart from not supporting
> + * receiving of file handles as well as beginning the read at the
> + * passed @offset
> + *
> + */
> +ssize_t qio_channel_preadv_full(QIOChannel *ioc, const struct iovec *iov,
> + size_t niov, off_t offset, Error **errp);
"preadv"
> +
> +/**
> + * qio_channel_preadv
> + * @ioc: the channel object
> + * @buf: the memory region to write data into
> + * @buflen: the number of bytes to @buf
> + * @offset: offset in the channel where writes should begin
> + * @errp: pointer to a NULL-initialized error object
> + *
> + * Not all implementations will support this facility, so may report
> + * an error. To avoid errors, the caller may check for the feature
> + * flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method.
> + *
> + */
> +ssize_t qio_channel_preadv(QIOChannel *ioc, char *buf, size_t buflen,
> + off_t offset, Error **errp);
"pread"
With regards,
Daniel
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- Re: [PATCH v2 06/29] migration: Add auto-pause capability, (continued)
- Re: [PATCH v2 06/29] migration: Add auto-pause capability, Daniel P . Berrangé, 2023/10/25
- Re: [PATCH v2 06/29] migration: Add auto-pause capability, Peter Xu, 2023/10/25
- Re: [PATCH v2 06/29] migration: Add auto-pause capability, Daniel P . Berrangé, 2023/10/25
- Re: [PATCH v2 06/29] migration: Add auto-pause capability, Peter Xu, 2023/10/25
- Re: [PATCH v2 06/29] migration: Add auto-pause capability, Daniel P . Berrangé, 2023/10/25
- Re: [PATCH v2 06/29] migration: Add auto-pause capability, Peter Xu, 2023/10/25
[PATCH v2 07/29] migration: Run "file:" migration with a stopped VM, Fabiano Rosas, 2023/10/23
[PATCH v2 08/29] tests/qtest: File migration auto-pause tests, Fabiano Rosas, 2023/10/23
[PATCH v2 09/29] io: add and implement QIO_CHANNEL_FEATURE_SEEKABLE for channel file, Fabiano Rosas, 2023/10/23
[PATCH v2 10/29] io: Add generic pwritev/preadv interface, Fabiano Rosas, 2023/10/23
- Re: [PATCH v2 10/29] io: Add generic pwritev/preadv interface,
Daniel P . Berrangé <=
[PATCH v2 11/29] io: implement io_pwritev/preadv for QIOChannelFile, Fabiano Rosas, 2023/10/23
[PATCH v2 12/29] migration/qemu-file: add utility methods for working with seekable channels, Fabiano Rosas, 2023/10/23
[PATCH v2 13/29] migration: fixed-ram: Add URI compatibility check, Fabiano Rosas, 2023/10/23
[PATCH v2 14/29] migration/ram: Introduce 'fixed-ram' migration capability, Fabiano Rosas, 2023/10/23