On Tue, 10 Feb 2026 06:44:59 +0000 Smita Koralahalli <[email protected]> wrote:
> Add helpers to register, queue and flush the deferred work. > > These helpers allow dax_hmem to execute ownership resolution outside the > probe context before dax_cxl binds. > > Signed-off-by: Smita Koralahalli <[email protected]> The sanity checks on valid inputs to me seem excessive for something that is intended to have a very narrow usecase. I'm also not sure it's harmful to just not bother with the parameter checking. Otherwise seems fine to me. > --- > drivers/dax/bus.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++ > drivers/dax/bus.h | 7 ++++++ > 2 files changed, 65 insertions(+) > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index 5f387feb95f0..92b88952ede1 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -25,6 +25,64 @@ DECLARE_RWSEM(dax_region_rwsem); > */ > DECLARE_RWSEM(dax_dev_rwsem); > > +static DEFINE_MUTEX(dax_hmem_lock); > +static dax_hmem_deferred_fn hmem_deferred_fn; > +static void *dax_hmem_data; > + > +static void hmem_deferred_work(struct work_struct *work) > +{ > + dax_hmem_deferred_fn fn; > + void *data; > + > + scoped_guard(mutex, &dax_hmem_lock) { > + fn = hmem_deferred_fn; > + data = dax_hmem_data; > + } > + > + if (fn) > + fn(data); > +} > + > +static DECLARE_WORK(dax_hmem_work, hmem_deferred_work); > + > +int dax_hmem_register_work(dax_hmem_deferred_fn fn, void *data) > +{ > + guard(mutex)(&dax_hmem_lock); > + > + if (hmem_deferred_fn) > + return -EINVAL; What happens if we drop the check and therefore need to return int from these + handle errors? The worst that happens is hmem_deferred_fn == NULL and we set the data (might also be NULL, we don't care). To me that looks harmless. > + > + hmem_deferred_fn = fn; > + dax_hmem_data = data; > + return 0; > +} > +EXPORT_SYMBOL_GPL(dax_hmem_register_work); > + > +int dax_hmem_unregister_work(dax_hmem_deferred_fn fn, void *data) > +{ > + guard(mutex)(&dax_hmem_lock); > + > + if (hmem_deferred_fn != fn || dax_hmem_data != data) > + return -EINVAL; Do we need the sanity check? I'd just unconditionally clear them both. > + > + hmem_deferred_fn = NULL; > + dax_hmem_data = NULL; > + return 0; > +} > +EXPORT_SYMBOL_GPL(dax_hmem_unregister_work); > + > +void dax_hmem_queue_work(void) > +{ > + queue_work(system_long_wq, &dax_hmem_work); > +} > +EXPORT_SYMBOL_GPL(dax_hmem_queue_work); > + > +void dax_hmem_flush_work(void) > +{ > + flush_work(&dax_hmem_work); > +} > +EXPORT_SYMBOL_GPL(dax_hmem_flush_work); > + > #define DAX_NAME_LEN 30 > struct dax_id { > struct list_head list; > diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h > index cbbf64443098..b58a88e8089c 100644 > --- a/drivers/dax/bus.h > +++ b/drivers/dax/bus.h > @@ -41,6 +41,13 @@ struct dax_device_driver { > void (*remove)(struct dev_dax *dev); > }; > > +typedef void (*dax_hmem_deferred_fn)(void *data); > + > +int dax_hmem_register_work(dax_hmem_deferred_fn fn, void *data); > +int dax_hmem_unregister_work(dax_hmem_deferred_fn fn, void *data); > +void dax_hmem_queue_work(void); > +void dax_hmem_flush_work(void); > + > int __dax_driver_register(struct dax_device_driver *dax_drv, > struct module *module, const char *mod_name); > #define dax_driver_register(driver) \
