| Message ID | 49B02DB5.7020301@austin.ibm.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Commit | c5785f9e1c1c07c791fdc471f5c7fda4a5855b0c |
| Delegated to: | Benjamin Herrenschmidt |
| Headers | show |
On Thu, 2009-03-05 at 13:53 -0600, Nathan Fontenot wrote: > The return code from invoking the notifier chain when updating the > ibm,dynamic-memory property is not handled properly. In failure > cases (rc == NOTIFY_BAD) we should be restoring the original value > of the property. In success (rc == NOTIFY_OK) we should be returning > zero from the calling routine. This is actually not clear to me ... if the memory has been added or removed, we must make sure the device-tree is up to date... ie, we can't tell the firmware that we failed can we ? Ben. > Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> > --- > arch/powerpc/platforms/pseries/reconfig.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > Index: linux-2.6/arch/powerpc/platforms/pseries/reconfig.c > =================================================================== > --- linux-2.6.orig/arch/powerpc/platforms/pseries/reconfig.c 2008-10-23 22:29:24.000000000 -0500 > +++ linux-2.6/arch/powerpc/platforms/pseries/reconfig.c 2009-03-05 13:20:00.000000000 -0600 > @@ -468,9 +468,13 @@ > > rc = blocking_notifier_call_chain(&pSeries_reconfig_chain, > action, value); > + if (rc == NOTIFY_BAD) { > + rc = prom_update_property(np, oldprop, newprop); > + return -ENOMEM; > + } > } > > - return rc; > + return 0; > } > > /** > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@ozlabs.org > https://ozlabs.org/mailman/listinfo/linuxppc-dev
Benjamin Herrenschmidt wrote: > On Thu, 2009-03-05 at 13:53 -0600, Nathan Fontenot wrote: >> The return code from invoking the notifier chain when updating the >> ibm,dynamic-memory property is not handled properly. In failure >> cases (rc == NOTIFY_BAD) we should be restoring the original value >> of the property. In success (rc == NOTIFY_OK) we should be returning >> zero from the calling routine. > > This is actually not clear to me ... if the memory has been added or > removed, we must make sure the device-tree is up to date... ie, we can't > tell the firmware that we failed can we ? > Once the memory is added or removed the device tree is updated to reflect the change. The case for systems where the memory in the device tree is specified in the ibm,dynamic-reconfiguration-memory/ibm,dynamic-memory property is slightly different. Because it is a property that is being updated (as opposed to addition or removal of a device tree node for memory specified as memory@XXXX nodes) The kernel updates the property in the device tree then invokes the notifier chain. If anyone on the notifier chain returns a failure we should restore the property to its previous value. I think that part is understood. The main user (and probably only user) of this interface is the drmgr tool that handles DLPAR of memory and other conmponents. The drmgr tool tries to update the property after acquiring it from firmware. If the property update fails, drmgr cleans up and returns the memory to firmware. This update ensures that the device tree property is not left in a state that implies that the system owns the memory. Hope that helps. -Nathan > Ben. > >> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> >> --- >> arch/powerpc/platforms/pseries/reconfig.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> Index: linux-2.6/arch/powerpc/platforms/pseries/reconfig.c >> =================================================================== >> --- linux-2.6.orig/arch/powerpc/platforms/pseries/reconfig.c 2008-10-23 22:29:24.000000000 -0500 >> +++ linux-2.6/arch/powerpc/platforms/pseries/reconfig.c 2009-03-05 13:20:00.000000000 -0600 >> @@ -468,9 +468,13 @@ >> >> rc = blocking_notifier_call_chain(&pSeries_reconfig_chain, >> action, value); >> + if (rc == NOTIFY_BAD) { >> + rc = prom_update_property(np, oldprop, newprop); >> + return -ENOMEM; >> + } >> } >> >> - return rc; >> + return 0; >> } >> >> /** >> _______________________________________________ >> Linuxppc-dev mailing list >> Linuxppc-dev@ozlabs.org >> https://ozlabs.org/mailman/listinfo/linuxppc-dev >
Index: linux-2.6/arch/powerpc/platforms/pseries/reconfig.c =================================================================== --- linux-2.6.orig/arch/powerpc/platforms/pseries/reconfig.c 2008-10-23 22:29:24.000000000 -0500 +++ linux-2.6/arch/powerpc/platforms/pseries/reconfig.c 2009-03-05 13:20:00.000000000 -0600 @@ -468,9 +468,13 @@ rc = blocking_notifier_call_chain(&pSeries_reconfig_chain, action, value); + if (rc == NOTIFY_BAD) { + rc = prom_update_property(np, oldprop, newprop); + return -ENOMEM; + } } - return rc; + return 0; } /**
The return code from invoking the notifier chain when updating the ibm,dynamic-memory property is not handled properly. In failure cases (rc == NOTIFY_BAD) we should be restoring the original value of the property. In success (rc == NOTIFY_OK) we should be returning zero from the calling routine. Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com> --- arch/powerpc/platforms/pseries/reconfig.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)