On Wed, Feb 25, 2015 at 04:51:30PM +0000, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> Postcopy needs a method to send messages from the destination back to
> the source, this is the 'return path'.
>
> Wire it up for 'socket' QEMUFile's using a dup'd fd.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> include/migration/qemu-file.h | 7 +++++
> migration/qemu-file-internal.h | 2 ++
> migration/qemu-file-unix.c | 58
> +++++++++++++++++++++++++++++++++++-------
> migration/qemu-file.c | 12 +++++++++
> 4 files changed, 70 insertions(+), 9 deletions(-)
>
> diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
> index 6ae0b03..3c38963 100644
> --- a/include/migration/qemu-file.h
> +++ b/include/migration/qemu-file.h
> @@ -85,6 +85,11 @@ typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
> int *bytes_sent);
>
> /*
> + * Return a QEMUFile for comms in the opposite direction
> + */
> +typedef QEMUFile *(QEMURetPathFunc)(void *opaque);
> +
> +/*
> * Stop any read or write (depending on flags) on the underlying
> * transport on the QEMUFile.
> * Existing blocking reads/writes must be woken
> @@ -102,6 +107,7 @@ typedef struct QEMUFileOps {
> QEMURamHookFunc *after_ram_iterate;
> QEMURamHookFunc *hook_ram_load;
> QEMURamSaveFunc *save_page;
> + QEMURetPathFunc *get_return_path;
> QEMUFileShutdownFunc *shut_down;
> } QEMUFileOps;
>
> @@ -188,6 +194,7 @@ int64_t qemu_file_get_rate_limit(QEMUFile *f);
> int qemu_file_get_error(QEMUFile *f);
> void qemu_file_set_error(QEMUFile *f, int ret);
> int qemu_file_shutdown(QEMUFile *f);
> +QEMUFile *qemu_file_get_return_path(QEMUFile *f);
> void qemu_fflush(QEMUFile *f);
>
> static inline void qemu_put_be64s(QEMUFile *f, const uint64_t *pv)
> diff --git a/migration/qemu-file-internal.h b/migration/qemu-file-internal.h
> index d95e853..a39b8e3 100644
> --- a/migration/qemu-file-internal.h
> +++ b/migration/qemu-file-internal.h
> @@ -48,6 +48,8 @@ struct QEMUFile {
> unsigned int iovcnt;
>
> int last_error;
> +
> + struct QEMUFile *return_path;
AFAICT, the only thing this field is used for is an assert, which
seems a bit pointless. I'd suggest either getting rid of it, or
make qemu_file_get_return_path() safely idempotent by having it only
call the FileOps pointer if QEMUFile::return_path is non-NULL,
otherwise just return the existing return_path.
Setting the field probably belongs better in the wrapper than in the
socket specific callback, too, since there's nothing inherently
related to the socket implementation about it.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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