On 11/5/21 16:46, Dan Williams wrote: > On Fri, Nov 5, 2021 at 5:10 AM Joao Martins <joao.m.martins@xxxxxxxxxx> wrote: >> >> On 11/5/21 00:31, Dan Williams wrote: >>> On Fri, Aug 27, 2021 at 7:59 AM Joao Martins <joao.m.martins@xxxxxxxxxx> wrote: >>>> >>>> Right now, only static dax regions have a valid @pgmap pointer in its >>>> struct dev_dax. Dynamic dax case however, do not. >>>> >>>> In preparation for device-dax compound devmap support, make sure that >>>> dev_dax pgmap field is set after it has been allocated and initialized. >>>> >>>> dynamic dax device have the @pgmap is allocated at probe() and it's >>>> managed by devm (contrast to static dax region which a pgmap is provided >>>> and dax core kfrees it). So in addition to ensure a valid @pgmap, clear >>>> the pgmap when the dynamic dax device is released to avoid the same >>>> pgmap ranges to be re-requested across multiple region device reconfigs. >>>> >>>> Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx> >>>> Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx> >>>> --- >>>> drivers/dax/bus.c | 8 ++++++++ >>>> drivers/dax/device.c | 2 ++ >>>> 2 files changed, 10 insertions(+) >>>> >>>> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c >>>> index 6cc4da4c713d..49dbff9ba609 100644 >>>> --- a/drivers/dax/bus.c >>>> +++ b/drivers/dax/bus.c >>>> @@ -363,6 +363,14 @@ void kill_dev_dax(struct dev_dax *dev_dax) >>>> >>>> kill_dax(dax_dev); >>>> unmap_mapping_range(inode->i_mapping, 0, 0, 1); >>>> + >>>> + /* >>>> + * Dynamic dax region have the pgmap allocated via dev_kzalloc() >>>> + * and thus freed by devm. Clear the pgmap to not have stale pgmap >>>> + * ranges on probe() from previous reconfigurations of region devices. >>>> + */ >>>> + if (!is_static(dev_dax->region)) >>>> + dev_dax->pgmap = NULL; >>>> } >>>> EXPORT_SYMBOL_GPL(kill_dev_dax); >>>> >>>> diff --git a/drivers/dax/device.c b/drivers/dax/device.c >>>> index 0b82159b3564..6e348b5f9d45 100644 >>>> --- a/drivers/dax/device.c >>>> +++ b/drivers/dax/device.c >>>> @@ -426,6 +426,8 @@ int dev_dax_probe(struct dev_dax *dev_dax) >>>> } >>>> >>>> pgmap->type = MEMORY_DEVICE_GENERIC; >>>> + dev_dax->pgmap = pgmap; >>> >>> So I think I'd rather see a bigger patch that replaces some of the >>> implicit dev_dax->pgmap == NULL checks with explicit is_static() >>> checks. Something like the following only compile and boot tested... >>> Note the struct_size() change probably wants to be its own cleanup, >>> and the EXPORT_SYMBOL_NS_GPL(..., DAX) probably wants to be its own >>> patch converting over the entirety of drivers/dax/. Thoughts? >>> >> It's a good idea. Certainly the implicit pgmap == NULL made it harder >> than the necessary to find where the problem was. So turning those checks >> into explicit checks that differentiate static vs dynamic dax will help >> >> With respect to this series converting those pgmap == NULL is going to need >> to made me export the symbol (provided dax core and dax device can be built >> as modules). So I don't know how this can be a patch converting entirety of >> dax. Perhaps you mean that I would just EXPORT_SYMBOL() and then a bigger >> patch introduces the MODULE_NS_IMPORT() And EXPORT_SYMBOL_NS*() separately. > > Yeah, either a lead-in patch to do the conversion, or a follow on to > convert everything after the fact. Either way works for me, but I have > a small preference for the lead-in patch. > The one reason I am leaning towards the after the fact conversion, is that the addition of a new exported symbol looks unrelated to a drivers/dax wide conversion to namespaced symbols. Looks like a separate cleanup on top of this series, as opposed to a dependency cleanup. >>> EXPORT_SYMBOL_GPL(kill_dev_dax); >>> >>> diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h >>> index 1e946ad7780a..4acdfee7dd59 100644 >>> --- a/drivers/dax/bus.h >>> +++ b/drivers/dax/bus.h >>> @@ -48,6 +48,7 @@ int __dax_driver_register(struct dax_device_driver *dax_drv, >>> __dax_driver_register(driver, THIS_MODULE, KBUILD_MODNAME) >>> void dax_driver_unregister(struct dax_device_driver *dax_drv); >>> void kill_dev_dax(struct dev_dax *dev_dax); >>> +bool static_dev_dax(struct dev_dax *dev_dax); >>> >>> #if IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT) >>> int dev_dax_probe(struct dev_dax *dev_dax); >>> diff --git a/drivers/dax/device.c b/drivers/dax/device.c >>> index dd8222a42808..87507aff2b10 100644 >>> --- a/drivers/dax/device.c >>> +++ b/drivers/dax/device.c >>> @@ -398,31 +398,43 @@ int dev_dax_probe(struct dev_dax *dev_dax) >>> void *addr; >>> int rc, i; >>> >>> - pgmap = dev_dax->pgmap; >>> - if (dev_WARN_ONCE(dev, pgmap && dev_dax->nr_range > 1, >>> - "static pgmap / multi-range device conflict\n")) >>> + if (static_dev_dax(dev_dax) && dev_dax->nr_range > 1) { >>> + dev_warn(dev, "static pgmap / multi-range device conflict\n"); >>> return -EINVAL; >>> + } >>> >>> - if (!pgmap) { >>> - pgmap = devm_kzalloc(dev, sizeof(*pgmap) + sizeof(struct range) >>> - * (dev_dax->nr_range - 1), GFP_KERNEL); >>> + if (static_dev_dax(dev_dax)) { >>> + pgmap = dev_dax->pgmap; >>> + } else { >>> + if (dev_dax->pgmap) { >>> + dev_warn(dev, >>> + "dynamic-dax with pre-populated page map!?\n"); >>> + return -EINVAL; >>> + } >>> + pgmap = devm_kzalloc( >>> + dev, struct_size(pgmap, ranges, dev_dax->nr_range - 1), >>> + GFP_KERNEL); >>> if (!pgmap) >>> return -ENOMEM; >>> pgmap->nr_range = dev_dax->nr_range; >>> + dev_dax->pgmap = pgmap; >>> + for (i = 0; i < dev_dax->nr_range; i++) { >>> + struct range *range = &dev_dax->ranges[i].range; >>> + >>> + pgmap->ranges[i] = *range; >>> + } >>> } >>> >> This code move is probably not needed unless your point is to have a more clear >> separation on what's initialization versus the mem region request (that's >> applicable to both dynamic and static). > > It was more of an RFC cleanup idea and yes, should be its own patch if > you think it helps make the init path clearer. > OK.