efd1535 xen-blkfront: don't call talk_to_blkback when already connected to blkback and 2a6f71a xen-blkfront: fix resume issues after a migration

[Konrad Rzeszutek Wilk]

Heya!

Please put on the 4.6 stable tree these two following patches:

2a6f71a xen-blkfront: fix resume issues after a migration
efd1535 xen-blkfront: don't call talk_to_blkback when already connected to blkback

And for the 4.5 stable tree:

2a6f71a xen-blkfront: fix resume issues after a migration

The impact is that without these patches the migration of a guest
using Linux v4.5, or v4.6 falls on its face.

Thanks.

P.S.
When I sent the patch to Jens Axboe I forgot to put Cc: stable@xxxxxxxxxxxxxxx
on it. Sorry!