Re: [Qemu-devel] [PATCH v4 01/30] vmstate: reduce code duplication

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Mar 31, 2014 at 04:01:34PM +0100, Dr. David Alan Gilbert wrote:
> * Michael S. Tsirkin (mst@redhat.com) wrote:
> > move size offset and number of elements math out
> > to functions, to reduce code duplication.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  vmstate.c | 97 ++++++++++++++++++++++++++++++++++-----------------------------
> >  1 file changed, 52 insertions(+), 45 deletions(-)
> > 
> > diff --git a/vmstate.c b/vmstate.c
> > index b689f2f..dc99e1a 100644
> > --- a/vmstate.c
> > +++ b/vmstate.c
> > @@ -10,6 +10,50 @@ static void vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
> >  static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
> >                                     void *opaque);
> >  
> > +static int vmstate_n_elems(void *opaque, VMStateField *field)
> > +{
> > +    int n_elems = 1;
> > +
> > +    if (field->flags & VMS_ARRAY) {
> > +        n_elems = field->num;
> > +    } else if (field->flags & VMS_VARRAY_INT32) {
> > +        n_elems = *(int32_t *)(opaque+field->num_offset);
> > +    } else if (field->flags & VMS_VARRAY_UINT32) {
> > +        n_elems = *(uint32_t *)(opaque+field->num_offset);
> > +    } else if (field->flags & VMS_VARRAY_UINT16) {
> > +        n_elems = *(uint16_t *)(opaque+field->num_offset);
> > +    } else if (field->flags & VMS_VARRAY_UINT8) {
> > +        n_elems = *(uint8_t *)(opaque+field->num_offset);
> > +    }
> > +
> > +    return n_elems;
> > +}
> > +
> > +static int vmstate_size(void *opaque, VMStateField *field)
> > +{
> > +    int size = field->size;
> > +
> > +    if (field->flags & VMS_VBUFFER) {
> > +        size = *(int32_t *)(opaque+field->size_offset);
> > +        if (field->flags & VMS_MULTIPLY) {
> > +            size *= field->size;
> > +        }
> > +    }
> > +
> > +    return size;
> > +}
> > +
> > +static void *vmstate_base_addr(void *opaque, VMStateField *field)
> > +{
> > +    void *base_addr = opaque + field->offset;
> > +
> > +    if (field->flags & VMS_POINTER) {
> > +        base_addr = *(void **)base_addr + field->start;
> > +    }
> > +
> > +    return base_addr;
> > +}
> > +
> >  int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
> >                         void *opaque, int version_id)
> >  {
> > @@ -36,30 +80,10 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd,
> >               field->field_exists(opaque, version_id)) ||
> >              (!field->field_exists &&
> >               field->version_id <= version_id)) {
> > -            void *base_addr = opaque + field->offset;
> > -            int i, n_elems = 1;
> > -            int size = field->size;
> > -
> > -            if (field->flags & VMS_VBUFFER) {
> > -                size = *(int32_t *)(opaque+field->size_offset);
> > -                if (field->flags & VMS_MULTIPLY) {
> > -                    size *= field->size;
> > -                }
> > -            }
> > -            if (field->flags & VMS_ARRAY) {
> > -                n_elems = field->num;
> > -            } else if (field->flags & VMS_VARRAY_INT32) {
> > -                n_elems = *(int32_t *)(opaque+field->num_offset);
> > -            } else if (field->flags & VMS_VARRAY_UINT32) {
> > -                n_elems = *(uint32_t *)(opaque+field->num_offset);
> > -            } else if (field->flags & VMS_VARRAY_UINT16) {
> > -                n_elems = *(uint16_t *)(opaque+field->num_offset);
> > -            } else if (field->flags & VMS_VARRAY_UINT8) {
> > -                n_elems = *(uint8_t *)(opaque+field->num_offset);
> > -            }
> > -            if (field->flags & VMS_POINTER) {
> > -                base_addr = *(void **)base_addr + field->start;
> > -            }
> > +            void *base_addr = vmstate_base_addr(opaque, field);
> > +            int i, n_elems = vmstate_n_elems(opaque, field);
> > +            int size = vmstate_size(opaque, field);
> > +
> >              for (i = 0; i < n_elems; i++) {
> >                  void *addr = base_addr + size * i;
> >  
> > @@ -102,27 +126,10 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
> >      while (field->name) {
> >          if (!field->field_exists ||
> >              field->field_exists(opaque, vmsd->version_id)) {
> > -            void *base_addr = opaque + field->offset;
> > -            int i, n_elems = 1;
> > -            int size = field->size;
> > -
> > -            if (field->flags & VMS_VBUFFER) {
> > -                size = *(int32_t *)(opaque+field->size_offset);
> > -                if (field->flags & VMS_MULTIPLY) {
> > -                    size *= field->size;
> > -                }
> > -            }
> > -            if (field->flags & VMS_ARRAY) {
> > -                n_elems = field->num;
> > -            } else if (field->flags & VMS_VARRAY_INT32) {
> > -                n_elems = *(int32_t *)(opaque+field->num_offset);
> > -            } else if (field->flags & VMS_VARRAY_UINT32) {
> > -                n_elems = *(uint32_t *)(opaque+field->num_offset);
> > -            } else if (field->flags & VMS_VARRAY_UINT16) {
> > -                n_elems = *(uint16_t *)(opaque+field->num_offset);
> > -            } else if (field->flags & VMS_VARRAY_UINT8) {
> > -                n_elems = *(uint8_t *)(opaque+field->num_offset);
> > -            }
> > +            void *base_addr = vmstate_base_addr(opaque, field);
> > +            int i, n_elems = vmstate_n_elems(opaque, field);
> > +            int size = vmstate_size(opaque, field);
> > +
> >              if (field->flags & VMS_POINTER) {
> >                  base_addr = *(void **)base_addr + field->start;
> >              }
> 
> Hmm, shouldn't those last 3 lines be deleted as well - the logic is
> now in vmstate_base_addr?
> 
> 
> Dave

So it should, thanks.


> > -- 
> > MST
> > 
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK