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Re: [Qemu-devel] [PATCH] docs/devel/migration.txt: keep functions consis
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH] docs/devel/migration.txt: keep functions consistent with the code |
Date: |
Tue, 5 Dec 2017 19:58:16 +0000 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
* Jay Zhou (address@hidden) wrote:
> Since the commit 11808bb0c422134bf09119f4aa22c59b0ce84bf3 removed
> the put_buffer callback and using an iovec based write handler instead,
> the docs should be sync with the code too.
>
> Signed-off-by: Jay Zhou <address@hidden>
Lets check with Dan (added to cc) since he wrote 11808bb;
it might be best just to rever to migration/qemu-file.h for an
explanation of each function.
Dave
> ---
> docs/devel/migration.txt | 31 ++++++++++++++++++-------------
> 1 file changed, 18 insertions(+), 13 deletions(-)
>
> diff --git a/docs/devel/migration.txt b/docs/devel/migration.txt
> index 4030703..e7b08c9 100644
> --- a/docs/devel/migration.txt
> +++ b/docs/devel/migration.txt
> @@ -52,26 +52,31 @@ QEMU uses a QEMUFile abstraction to be able to do
> migration. Any type
> of migration that wants to use QEMU infrastructure has to create a
> QEMUFile with:
>
> -QEMUFile *qemu_fopen_ops(void *opaque,
> - QEMUFilePutBufferFunc *put_buffer,
> - QEMUFileGetBufferFunc *get_buffer,
> - QEMUFileCloseFunc *close);
> +typedef struct QEMUFileOps {
> + QEMUFileGetBufferFunc *get_buffer;
> + QEMUFileCloseFunc *close;
> + QEMUFileSetBlocking *set_blocking;
> + QEMUFileWritevBufferFunc *writev_buffer;
> + QEMURetPathFunc *get_return_path;
> + QEMUFileShutdownFunc *shut_down;
> +} QEMUFileOps;
>
> -The functions have the following functionality:
> +QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
>
> -This function writes a chunk of data to a file at the given position.
> -The pos argument can be ignored if the file is only used for
> -streaming. The handler should try to write all of the data it can.
> +The main functions of QEMUFileOps have the following functionality:
>
> -typedef int (QEMUFilePutBufferFunc)(void *opaque, const uint8_t *buf,
> - int64_t pos, int size);
> +This function writes an iovec to file. The handler must write all
> +of the data or return a negative errno value.
> +
> +typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
> + int iovcnt, int64_t pos);
>
> Read a chunk of data from a file at the given position. The pos argument
> can be ignored if the file is only be used for streaming. The number of
> bytes actually read should be returned.
>
> -typedef int (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
> - int64_t pos, int size);
> +typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
> + int64_t pos, int size);
>
> Close a file and return an error code.
>
> @@ -80,7 +85,7 @@ typedef int (QEMUFileCloseFunc)(void *opaque);
> You can use any internal state that you need using the opaque void *
> pointer that is passed to all functions.
>
> -The important functions for us are put_buffer()/get_buffer() that
> +The important functions for us are writev_buffer()/get_buffer() that
> allow to write/read a buffer into the QEMUFile.
>
> === How to save the state of one device ===
> --
> 1.8.3.1
>
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK