Pull block fixes from Jens Axboe:
"This contains a set of fixes for xen-blkback by way of Konrad, and a
performance regression fix for blk-mq for shared tags.
The latter could account for as much as a 50x reduction in
performance, with the test case from the user with 500 name spaces. A
more realistic setup on my end with 32 drives showed a 3.5x drop. The
fix has been thoroughly tested before being committed"
* 'for-linus' of git://git.kernel.dk/linux-block:
blk-mq: fix performance regression with shared tags
xen-blkback: don't leak stack data via response ring
xen/blkback: don't use xen_blkif_get() in xen-blkback kthread
xen/blkback: don't free be structure too early
xen/blkback: fix disconnect while I/Os in flight