Re: [PATCHv5 00/14] xen: fix many long-standing grant mapping bugs

[David Vrabel <david.vrabel@citrix.com>]

On 27/01/15 16:44, David Vrabel wrote:
> This series fixes a number of long-standing bugs in the handling of
> grant maps.  Refer to the following for all the details.
> 
>   http://xenbits.xen.org/people/dvrabel/grant-improvements-C.pdf
> 
> In summary, the important uses that this enables are:
> 
> 1. Block backends can use networked storage safely.
> 
> 2. Block backends can use network storage provided by other guests on
>    the same host.
> 
> 3. User space block backends can use direct I/O or asynchronous I/O.
> 
> The first two patches are the core MM changes necessary.  These have
> already been acked.
> 
> Patches #3 and #4 remove existing (broken) mechanisms.  This does
> temporarily break some previously working use cases, but it does make
> the subsequent additions much easier to review.
> 
> Only patches #3, #4, and #13 need acks from other Xen maintainers.
> 
> As a happy side effect, performance is also likely to be improved in
> some areas (but I've not got any measurements yet).  User space
> backends using grant mapping should see some good improvements from
> reduced overheads and better unmap batching.  VIF to VIF network
> traffic may also see a small improvement.
> 
> Finally, thanks to Jenny who did much of the implementation.

Applied to devel/for-linus-3.20.

David