linux/drivers/dax
Dan Williams 70aab281e1 dax: Introduce alloc_dev_dax_id()
The reference counting of dax_region objects is needlessly complicated,
has lead to confusion [1], and has hidden a bug [2]. Towards cleaning up
that mess introduce alloc_dev_dax_id() to minimize the holding of a
dax_region reference to only what dev_dax_release() needs, the
dax_region->ida.

Part of the reason for the mess was the design to dereference a
dax_region in all cases in free_dev_dax_id() even if the id was
statically assigned by the upper level dax_region driver. Remove the
need to call "is_static(dax_region)" by tracking whether the id is
dynamic directly in the dev_dax instance itself.

With that flag the dax_region pinning and release per dev_dax instance
can move to alloc_dev_dax_id() and free_dev_dax_id() respectively.

A follow-on cleanup address the unnecessary references in the dax_region
setup and drivers.

Fixes: 0f3da14a4f ("device-dax: introduce 'seed' devices")
Link: http://lore.kernel.org/r/20221203095858.612027-1-liuyongqiang13@huawei.com [1]
Link: http://lore.kernel.org/r/3cf0890b-4eb0-e70e-cd9c-2ecc3d496263@hpe.com [2]
Reported-by: Yongqiang Liu <liuyongqiang13@huawei.com>
Reported-by: Paul Cassella <cassella@hpe.com>
Reported-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/168577284563.1672036.13493034988900989554.stgit@dwillia2-xfh.jf.intel.com
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
2023-06-23 01:03:50 -06:00
..
hmem cxl/dax: Create dax devices for CXL RAM regions 2023-02-10 17:33:45 -08:00
pmem dax: Kill DEV_DAX_PMEM_COMPAT 2021-11-24 19:21:35 -08:00
bus.c dax: Introduce alloc_dev_dax_id() 2023-06-23 01:03:50 -06:00
bus.h dax: fix missing-prototype warnings 2023-05-18 17:28:07 -07:00
cxl.c cxl/dax: Create dax devices for CXL RAM regions 2023-02-10 17:33:45 -08:00
dax-private.h dax: Introduce alloc_dev_dax_id() 2023-06-23 01:03:50 -06:00
device.c dax: fix missing-prototype warnings 2023-05-18 17:28:07 -07:00
Kconfig cxl for v6.3 2023-02-25 09:19:23 -08:00
kmem.c dax/kmem: Fix leak of memory-hotplug resources 2023-02-17 14:58:01 -08:00
Makefile cxl/dax: Create dax devices for CXL RAM regions 2023-02-10 17:33:45 -08:00
pmem.c dax: Kill DEV_DAX_PMEM_COMPAT 2021-11-24 19:21:35 -08:00
super.c dax: super.c: fix kernel-doc bad line warning 2023-01-25 12:36:16 -08:00