cfq-iosched: move cfq_group determination from cfq_find_alloc_queue() to cfq_get_queue()
cfq-iosched: move cfq_group determination from cfq_find_alloc_queue() to cfq_get_queue()

This is necessary for making async cfq_cgroups per-cfq_group instead
of per-cfq_data.  While this change makes cfq_get_queue() perform RCU
locking and look up cfq_group even when it reuses async queue, the
extra overhead is extremely unlikely to be noticeable given that this
is already sitting behind cic->cfqq[] cache and the overall cost of
cfq operation.

Signed-off-by: Tejun Heo <546b05909706652891a87f7bfe385ae147f61f91@kernel.org>
Reviewed-by: Jeff Moyer <cd6badf7869d996b866599075536a600ed1910b5@redhat.com>
Cc: Vivek Goyal <61d11262d0d9873ddb5a887f48fcb04e8c5973d0@redhat.com>
Cc: Arianna Avanzini <20b1b82ea87150022f6495522a9f5e355ea8b305@gmail.com>
Signed-off-by: Jens Axboe <cd8c6775e60d6f67a6984377324e5290df3d5358@fb.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs