Re: PAGE_SIZE (64KB), while block driver 'struct request' deals with < PAGE_SIZE (up to 44Kb). Was:Re: [RFC] Support of non-indirect grant backend on 64KB guest

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Fri, Sep 04, 2015 at 05:15:13PM +0100, Julien Grall wrote:
> On 04/09/15 16:41, Konrad Rzeszutek Wilk wrote:
> >> Maybe we could fall back to the previous plan of modifying xen-blkfront
> >> for the moment?
> > 
> > Which afaic need to be reposted?
> 
> Right. Although I didn't see any comment on the patch. All the comments
> was about the problem. Does it mean that you and Roger are "happy" with
> the way it's done?

There were some #idef I think? And I recall seeing the segment limit being
advertised as PAGE_SIZE / 2?


I dug in the other block drivers to figure out what they
do when the underlaying storage cannot handle < PAGE_SIZE data.
And I couldn't find them. Which means this should be really dealt
on the drivers side (xen-blkfront) as an quirk.
 
Anyhow what I am going to do is - once it is reposted, force the
driver under x86 to work under this condition. That is disable
persistent support and only use 2048 .. and then drive some IO.
If all goes well I will send it in a git pull to Jens.
   

> 
> Regards,
> 
> -- 
> Julien Grall