block: Fix potential deadlock in blk_ia_range_sysfs_show()

In the Linux kernel, the following vulnerability has been resolved:

block: Fix potential deadlock in blk_ia_range_sysfs_show()

When being read, a sysfs attribute is already protected against removal

with the kobject node active reference counter. As a result, in

blk_ia_range_sysfs_show(), there is no need to take the queue sysfs

lock when reading the value of a range attribute. Using the queue sysfs

lock in this function creates a potential deadlock situation with the

disk removal, something that a lockdep signals with a splat when the

device is removed:

[ 760.703551] Possible unsafe locking scenario:

[ 760.703551]

[ 760.703554] CPU0 CPU1

[ 760.703556] ---- ----

[ 760.703558] lock(&q->sysfs_lock);

[ 760.703565] lock(kn->active#385);

[ 760.703573] lock(&q->sysfs_lock);

[ 760.703579] lock(kn->active#385);

[ 760.703587]

[ 760.703587] *** DEADLOCK ***

Solve this by removing the mutex_lock()/mutex_unlock() calls from

blk_ia_range_sysfs_show().