| Message ID | 52AA986C.7050305@jp.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Friday, December 13, 2013 02:17:32 PM Yasuaki Ishimatsu wrote: > (2013/12/13 13:56), Rafael J. Wysocki wrote: > > On Friday, December 13, 2013 11:56:32 AM Yasuaki Ishimatsu wrote: > >> Hi Rafael, > > > > Hi, > > > >> Please share your more detailed idea. I started to implement the following > >> idea. But the idea has one problem. > >> > >>>>> The eject work flow can be: > >>>>> (1) an eject event occurs, > >>>>> (2) the container "physical" device fails offline in acpi_scan_hot_remove() > >>>>> emmitting, say, KOBJ_CHANGE for the "physical" device, > >>>>> (3) user space notices the KOBJ_CHANGE and does the cleanup as needed, > >>>>> (4) user space changes the "physical" container device flag controlling > >>>>> offline to 0, > >>>>> (5) user space uses the sysfs "eject" attribute of the ACPI container object > >>>>> to finally eject the container, > >>>>> (6) the offline in acpi_scan_hot_remove() is now successful, because the > >>>>> flag controlling it has been set to 0 in step (4), > >>>>> (7) the "physical" container device goes away before executing _EJ0, > >>>>> (8) the container is ejected. > >> > >> I want to emit KOBJ_CHANGE before offlining devices on container device at (2). > >> But acpi_scan_hot_remove() offlines devices on container device at first. > >> So when offline container device, devices on container has been offlined. > >> > >> Thus the idea cannot fulfill my necessary feature. > > > > Well, in that case we need to treat containers in a special way at the ACPI > > level. Which is a bit unfortunate so to speak. > > > > To that end I'd try to add a new flag to struct acpi_hotplug_profile, say > > .verify_offline, such that if set, it would cause acpi_scan_hot_remove() to > > check if all of the "physical" companions of the top-level device are offline > > to start with, and if not, it would just emit KOBJ_CHANGE for the companions > > that are not offline and bail out. > > > > So the above algorithm would become: > > > > (1) an eject event occurs, > > (2) acpi_scan_hot_remove() checks the verify_offline flag in the target device's > > scan_handler structure, > > (3) if set (it would always be set for containers), acpi_scan_hot_remove() > > checks the status of the target device's "physical" companions; if at least > > one of them is offline, KOBJ_CHANGE is emitted for that "physical" device, > > and acpi_scan_hot_remove() returns, [I guess we can just emit KOBJ_CHANGE > > for the first companion that is not offline at this point.] > > (4) user space notices the KOBJ_CHANGE and does the cleanup as needed; in the > > process it carries out the offline operation for the container's "physical" > > companion (there's only one such companion for each container), [That > > operation for the container itself is trivial, but to succeed it requires > > all devices below the container to be taken offline in advance.] > > (5) user space uses the sysfs "eject" attribute of the ACPI container object > > to finally eject the container, > > (6) acpi_scan_hot_remove() is now successful, because the container's "physical" > > companion is now offline, > > (7) the "physical" container device goes away before executing _EJ0, > > (8) the container is ejected. > > > > I think that should work for you. > > This idea seems to same as your previous work. > http://lkml.org/lkml/2013/2/23/97 No, it is not. That one didn't involve physical device representations. > How about add autoremove flag into acpi_hotplug_profile and check it as follow: This is very similar to "enable" except that it generates the uevent and "enable" doesn't. You might as well modify "enable" to trigger a uevent if eject is not enabled (note that with the latest patches in linux-next "enable" only applies to eject). That said I don't think we should generate any uevents for struct acpi_device objects, because they are not devices. > --- > drivers/acpi/scan.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > index 5383c81..c43d110 100644 > --- a/drivers/acpi/scan.c > +++ b/drivers/acpi/scan.c > @@ -409,6 +409,11 @@ static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data) > ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED; > goto err_out; > } > + if (!handler->hotplug.autoremove) { > + kobject_uevent(&device->dev.kobj, KOBJ_CHANGE); > + ost_code = ACPI_OST_SC_EJECT_NON_SPECIFIC_FAILURE; > + goto err_out; > + } > acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST, > ACPI_OST_SC_EJECT_IN_PROGRESS, NULL); > break; > > Adding the check into "acpi_hotplug_notify_cb()", user need not change the > flag for removing container device by "sysfs eject". Which is utterly confusing. There is no reason whatsoever why the sysfs eject attribute should work differently from the event-triggered eject. Quite the opposite is the case: it should work in the same way in my opinion so that it is possible to test the eject code path using that attribute. I'm traveling now, but when I get back home (next week), I'll try to implement the thing I was talking about above. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 5383c81..c43d110 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -409,6 +409,11 @@ static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data) ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED; goto err_out; } + if (!handler->hotplug.autoremove) { + kobject_uevent(&device->dev.kobj, KOBJ_CHANGE); + ost_code = ACPI_OST_SC_EJECT_NON_SPECIFIC_FAILURE; + goto err_out; + } acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST, ACPI_OST_SC_EJECT_IN_PROGRESS, NULL); break;