@@ -573,6 +573,30 @@ static int initiator_cmp(void *priv, const struct list_head *a,
return ia->processor_pxm - ib->processor_pxm;
}
+static int initiators_to_nodemask(unsigned long *p_nodes)
+{
+ /*
+ * list_sort doesn't call @cmp (initiator_cmp) for 0 or 1 sized lists.
+ * For a single-initiator system with other memory-only nodes, this
+ * means an empty p_nodes mask, since that is set by initiator_cmp().
+ * Special case the singular list, and make sure the node mask gets set
+ * appropriately.
+ */
+ if (list_empty(&initiators))
+ return -ENXIO;
+
+ if (list_is_singular(&initiators)) {
+ struct memory_initiator *initiator = list_first_entry(
+ &initiators, struct memory_initiator, node);
+
+ set_bit(initiator->processor_pxm, p_nodes);
+ return 0;
+ }
+
+ list_sort(p_nodes, &initiators, initiator_cmp);
+ return 0;
+}
+
static void hmat_register_target_initiators(struct memory_target *target)
{
static DECLARE_BITMAP(p_nodes, MAX_NUMNODES);
@@ -609,7 +633,9 @@ static void hmat_register_target_initiators(struct memory_target *target)
* initiators.
*/
bitmap_zero(p_nodes, MAX_NUMNODES);
- list_sort(p_nodes, &initiators, initiator_cmp);
+ if (initiators_to_nodemask(p_nodes) < 0)
+ return;
+
if (!access0done) {
for (i = WRITE_LATENCY; i <= READ_BANDWIDTH; i++) {
loc = localities_types[i];
@@ -643,7 +669,9 @@ static void hmat_register_target_initiators(struct memory_target *target)
/* Access 1 ignores Generic Initiators */
bitmap_zero(p_nodes, MAX_NUMNODES);
- list_sort(p_nodes, &initiators, initiator_cmp);
+ if (initiators_to_nodemask(p_nodes) < 0)
+ return;
+
for (i = WRITE_LATENCY; i <= READ_BANDWIDTH; i++) {
loc = localities_types[i];
if (!loc)
In a system with a single initiator node, and one or more memory-only 'target' nodes, the memory-only node(s) would fail to register their initiator node correctly. i.e. in sysfs: # ls /sys/devices/system/node/node0/access0/targets/ node0 Where as the correct behavior should be: # ls /sys/devices/system/node/node0/access0/targets/ node0 node1 This happened because hmat_register_target_initiators() uses list_sort() to sort the initiator list, but the sort comparision function (initiator_cmp()) is overloaded to also set the node mask's bits. In a system with a single initiator, the list is singular, and list_sort elides the comparision helper call. Thus the node mask never gets set, and the subsequent search for the best initiator comes up empty. Add a new helper to sort the initiator list, and handle the singular list corner case by setting the node mask for that explicitly. Reported-by: Chris Piper <chris.d.piper@intel.com> Cc: <stable@vger.kernel.org> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Liu Shixin <liushixin2@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> --- drivers/acpi/numa/hmat.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-)