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| author |  Dan Williams <dan.j.williams@intel.com>
| 2023-06-02 23:14:05 -0700 |
|---|---|---|
| committer |  Vishal Verma <vishal.l.verma@intel.com>
| 2023-06-23 01:03:50 -0600 |
| commit | 70aab281e18c68a1284bc387de127c2fc0bed3f8 (patch) | |
| tree | a111f3edcc97d178f4050f74fefe95f6bbeececd /drivers/dax/dax-private.h | |
| parent | dax: Use device_unregister() in unregister_dax_mapping() (diff) | |
| download | linux-70aab281e18c68a1284bc387de127c2fc0bed3f8.tar.gz linux-70aab281e18c68a1284bc387de127c2fc0bed3f8.tar.bz2 linux-70aab281e18c68a1284bc387de127c2fc0bed3f8.zip | |
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: 0f3da14a4f05 ("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>
Diffstat (limited to 'drivers/dax/dax-private.h')
| -rw-r--r-- | drivers/dax/dax-private.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h index db032680d941..27cf2daaaa79 100644 --- a/drivers/dax/dax-private.h +++ b/drivers/dax/dax-private.h @@ -52,7 +52,8 @@ struct dax_mapping { * @region - parent region * @dax_dev - core dax functionality * @target_node: effective numa node if dev_dax memory range is onlined - * @id: ida allocated id + * @dyn_id: is this a dynamic or statically created instance + * @id: ida allocated id when the dax_region is not static * @ida: mapping id allocator * @dev - device core * @pgmap - pgmap for memmap setup / lifetime (driver owned) @@ -64,6 +65,7 @@ struct dev_dax { struct dax_device *dax_dev; unsigned int align; int target_node; + bool dyn_id; int id; struct ida ida; struct device dev; |