Re: [Qemu-devel] [PATCH COLO-Frame v10 11/38] QEMUSizedBuffer: Introduce two help functions for qsb

[zhanghailiang]

On 2015/11/7 2:30, Dr. David Alan Gilbert wrote:
> * zhanghailiang (address@hidden) wrote:
> > Introduce two new QEMUSizedBuffer APIs which will be used by COLO to buffer
> > VM state:
> > One is qsb_put_buffer(), which put the content of a given QEMUSizedBuffer
> > into QEMUFile, this is used to send buffered VM state to secondary.
> > Another is qsb_fill_buffer(), read 'size' bytes of data from the file into
> > qsb, this is used to get VM state from socket into a buffer.
> >
> > Signed-off-by: zhanghailiang <address@hidden>
> > Signed-off-by: Li Zhijian <address@hidden>
> > Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> >   include/migration/qemu-file.h |  3 ++-
> >   migration/qemu-file-buf.c     | 58 +++++++++++++++++++++++++++++++++++++++++++
> >   2 files changed, 60 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
> > index 29a338d..de42d5b 100644
> > --- a/include/migration/qemu-file.h
> > +++ b/include/migration/qemu-file.h
> > @@ -144,7 +144,8 @@ ssize_t qsb_get_buffer(const QEMUSizedBuffer *, off_t 
> > start, size_t count,
> >                          uint8_t *buf);
> >   ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t *buf,
> >                        off_t pos, size_t count);
> > -
> > +void qsb_put_buffer(QEMUFile *f, QEMUSizedBuffer *qsb, int size);
> > +int qsb_fill_buffer(QEMUSizedBuffer *qsb, QEMUFile *f, int size);
>
> I made most of the qemu_file use size_t back in August; cna you update
> this please.

Of course, Will do that in next version, thanks.

> Dave
>
> >   /*
> >    * For use on files opened with qemu_bufopen
> > diff --git a/migration/qemu-file-buf.c b/migration/qemu-file-buf.c
> > index 49516b8..e58004d 100644
> > --- a/migration/qemu-file-buf.c
> > +++ b/migration/qemu-file-buf.c
> > @@ -366,6 +366,64 @@ ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t 
> > *source,
> >       return count;
> >   }
> >
> > +
> > +/**
> > + * Put the content of a given QEMUSizedBuffer into QEMUFile.
> > + *
> > + * @f: A QEMUFile
> > + * @qsb: A QEMUSizedBuffer
> > + * @size: size of content to write
> > + */
> > +void qsb_put_buffer(QEMUFile *f, QEMUSizedBuffer *qsb, int size)
> > +{
> > +    int i, l;
> > +
> > +    for (i = 0; i < qsb->n_iov && size > 0; i++) {
> > +        l = MIN(qsb->iov[i].iov_len, size);
> > +        qemu_put_buffer(f, qsb->iov[i].iov_base, l);
> > +        size -= l;
> > +    }
> > +}
> > +
> > +/*
> > + * Read 'size' bytes of data from the file into qsb.
> > + * always fill from pos 0 and used after qsb_create().
> > + *
> > + * It will return size bytes unless there was an error, in which case it will
> > + * return as many as it managed to read (assuming blocking fd's which
> > + * all current QEMUFile are)
> > + */
> > +int qsb_fill_buffer(QEMUSizedBuffer *qsb, QEMUFile *f, int size)
> > +{
> > +    ssize_t rc = qsb_grow(qsb, size);
> > +    int pending = size, i;
> > +    qsb->used = 0;
> > +    uint8_t *buf = NULL;
> > +
> > +    if (rc < 0) {
> > +        return rc;
> > +    }
> > +
> > +    for (i = 0; i < qsb->n_iov && pending > 0; i++) {
> > +        int doneone = 0;
> > +        /* read until iov full */
> > +        while (doneone < qsb->iov[i].iov_len && pending > 0) {
> > +            int readone = 0;
> > +            buf = qsb->iov[i].iov_base;
> > +            readone = qemu_get_buffer(f, buf,
> > +                                MIN(qsb->iov[i].iov_len - doneone, pending));
> > +            if (readone == 0) {
> > +                return qsb->used;
> > +            }
> > +            buf += readone;
> > +            doneone += readone;
> > +            pending -= readone;
> > +            qsb->used += readone;
> > +        }
> > +    }
> > +    return qsb->used;
> > +}
> > +
> >   typedef struct QEMUBuffer {
> >       QEMUSizedBuffer *qsb;
> >       QEMUFile *file;
> > --
> > 1.8.3.1
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
>
> .