[PATCH v2] x86/resctrl: Don't stop walking closids when a locksetup group is found

From: James Morse
Date: Mon Jun 03 2019 - 13:29:33 EST

When a new control group is created __init_one_rdt_domain() walks all
the other closids to calculate the sets of used and unused bits.

If it discovers a pseudo_locksetup group, it breaks out of the loop.
This means any later closid doesn't get its used bits added to used_b.
These bits will then get set in unused_b, and added to the new
control group's configuration, even if they were marked as exclusive
for a later closid.

When encountering a pseudo_locksetup group, we should continue. This
is because "a resource group enters 'pseudo-locked' mode after the
schemata is written while the resource group is in 'pseudo-locksetup'
mode." When we find a pseudo_locksetup group, its configuration is
expected to be overwritten, we can skip it.

Fixes: dfe9674b04ff6 ("x86/intel_rdt: Enable entering of pseudo-locksetup mode")
Cc: <stable@xxxxxxxxxxxxxxx>
Acked-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Changes since v1:
* Removed braces round multi-line comment and whitespace after the if() block

arch/x86/kernel/cpu/resctrl/rdtgroup.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 333c177a2471..869cbef5da81 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2542,7 +2542,12 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
if (closid_allocated(i) && i != closid) {
mode = rdtgroup_mode_by_closid(i);
- break;
+ /*
+ * ctrl values for locksetup aren't relevant
+ * until the schemata is written, and the mode
+ */
+ continue;
* If CDP is active include peer domain's
* usage to ensure there is no overlap