FROMLIST: scsi: ufs: L2P map management for HPB read

This is a patch for managing L2P map in HPB module.

The HPB divides logical addresses into several regions. A region consists
of several sub-regions. The sub-region is a basic unit where L2P mapping is
managed. The driver loads L2P mapping data of each sub-region. The loaded
sub-region is called active-state. The HPB driver unloads L2P mapping data
as region unit. The unloaded region is called inactive-state.

Sub-region/region candidates to be loaded and unloaded are delivered from
the UFS device. The UFS device delivers the recommended active sub-region
and inactivate region to the driver using sensedata.
The HPB module performs L2P mapping management on the host through the
delivered information.

A pinned region is a pre-set regions on the UFS device that is always
activate-state.

The data structure for map data request and L2P map uses mempool API,
minimizing allocation overhead while avoiding static allocation.

The mininum size of the memory pool used in the HPB is implemented
as a module parameter, so that it can be configurable by the user.

To gurantee a minimum memory pool size of 4MB: ufshpb_host_map_kbytes=4096

The map_work manages active/inactive by 2 "to-do" lists.
Each hpb lun maintains 2 "to-do" lists:
  hpb->lh_inact_rgn - regions to be inactivated, and
  hpb->lh_act_srgn - subregions to be activated
Those lists are maintained on IO completion.

Bug: 183467926
Bug: 170940265
Bug: 183454255

Link: https://lore.kernel.org/linux-scsi/20210616070848epcms2p2819a1f0bf96cdcc357842fe8500af633@epcms2p2/



Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Can Guo <cang@codeaurora.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Acked-by: Avri Altman <Avri.Altman@wdc.com>
Tested-by: Bean Huo <beanhuo@micron.com>
Tested-by: Can Guo <cang@codeaurora.org>
Tested-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Daejun Park <daejun7.park@samsung.com>
Change-Id: I1284f326332e2d6f2c1221e2d64160939614ad2d