Introduce a global "DAX Regions" resource root and register each dax_region->res under it via request_resource(). Release the resource on dax_region teardown.
By enforcing a single global namespace for dax_region allocations, this ensures only one of dax_hmem or dax_cxl can successfully register a dax_region for a given range. Co-developed-by: Dan Williams <[email protected]> Signed-off-by: Dan Williams <[email protected]> Signed-off-by: Smita Koralahalli <[email protected]> --- drivers/dax/bus.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index fde29e0ad68b..5f387feb95f0 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -10,6 +10,7 @@ #include "dax-private.h" #include "bus.h" +static struct resource dax_regions = DEFINE_RES_MEM_NAMED(0, -1, "DAX Regions"); static DEFINE_MUTEX(dax_bus_lock); /* @@ -625,6 +626,8 @@ static void dax_region_unregister(void *region) { struct dax_region *dax_region = region; + scoped_guard(rwsem_write, &dax_region_rwsem) + release_resource(&dax_region->res); sysfs_remove_groups(&dax_region->dev->kobj, dax_region_attribute_groups); dax_region_put(dax_region); @@ -635,6 +638,7 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id, unsigned long flags) { struct dax_region *dax_region; + int rc; /* * The DAX core assumes that it can store its private data in @@ -667,14 +671,27 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id, .flags = IORESOURCE_MEM | flags, }; - if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) { - kfree(dax_region); - return NULL; + scoped_guard(rwsem_write, &dax_region_rwsem) + rc = request_resource(&dax_regions, &dax_region->res); + if (rc) { + dev_dbg(parent, "dax_region resource conflict for %pR\n", + &dax_region->res); + goto err_res; } + if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) + goto err_sysfs; + if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region)) return NULL; return dax_region; + +err_sysfs: + scoped_guard(rwsem_write, &dax_region_rwsem) + release_resource(&dax_region->res); +err_res: + kfree(dax_region); + return NULL; } EXPORT_SYMBOL_GPL(alloc_dax_region); -- 2.17.1
