Re: [Qemu-devel] [RFC PATCH v1 4/5] pc-bios/s390-ccw: Break up virtio-scsi read into multiples

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Wed, 26 Apr 2017 10:17:36 -0500
Eric Blake <eblake@redhat.com> wrote:

> On 04/26/2017 09:46 AM, Eric Farman wrote:
> > A virtio-scsi request that goes through the host sd driver and
> > exceeds the maximum transfer size is automatically broken up
> > for us. But the equivalent request going to the sg driver
> > presumes that any length requirements have already been honored.
> > Let's use the max_sectors field from the device and break up
> > all virtio-scsi requests (both sd and sg) to avoid problem from
> > the host drivers.
> > 
> > Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
> > ---
> >  pc-bios/s390-ccw/s390-ccw.h    |  4 ++++
> >  pc-bios/s390-ccw/virtio-scsi.c | 19 ++++++++++++++-----
> >  2 files changed, 18 insertions(+), 5 deletions(-)
> > 
> > diff --git a/pc-bios/s390-ccw/s390-ccw.h b/pc-bios/s390-ccw/s390-ccw.h
> > index ded67bc..e1f3751 100644
> > --- a/pc-bios/s390-ccw/s390-ccw.h
> > +++ b/pc-bios/s390-ccw/s390-ccw.h
> > @@ -42,6 +42,10 @@ typedef unsigned long long __u64;
> >  #ifndef NULL
> >  #define NULL    0
> >  #endif
> > +#ifndef MIN
> > +#define MIN(a, b) (((a) < (b)) ? (a) : (b));
> > +#endif
> 
> osdep.h defines MIN() for ALL files, so this hunk is spurious.
> 

This is a separate binary, which does not include the normal qemu
headers, though.