The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

48d4180939e1 ("ACPI: HMAT: Fix initiator registration for single-initiator systems") 14f16d47561b ("ACPI: HMAT: remove unnecessary variable initialization")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 48d4180939e12c4bd2846f984436d895bb9699ed Mon Sep 17 00:00:00 2001 From: Vishal Verma vishal.l.verma@intel.com Date: Wed, 16 Nov 2022 16:37:37 -0700 Subject: [PATCH] ACPI: HMAT: Fix initiator registration for single-initiator systems

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 consume the sorted initiator list, and generate the nodemask, decoupling it from the overloaded initiator_cmp() comparision callback. This prevents the singular list corner case naturally, and makes the code easier to follow as well.

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 Cc: Kirill A. Shutemov kirill.shutemov@linux.intel.com Reported-by: Chris Piper chris.d.piper@intel.com Signed-off-by: Vishal Verma vishal.l.verma@intel.com Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Link: https://lore.kernel.org/r/20221116-acpi_hmat_fix-v2-2-3712569be691@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com

diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c index 144a84f429ed..6cceca64a6bc 100644 --- a/drivers/acpi/numa/hmat.c +++ b/drivers/acpi/numa/hmat.c @@ -562,17 +562,26 @@ static int initiator_cmp(void *priv, const struct list_head *a, { struct memory_initiator *ia; struct memory_initiator *ib; - unsigned long *p_nodes = priv;

ia = list_entry(a, struct memory_initiator, node); ib = list_entry(b, struct memory_initiator, node);

- set_bit(ia->processor_pxm, p_nodes); - set_bit(ib->processor_pxm, p_nodes); - return ia->processor_pxm - ib->processor_pxm; }

+static int initiators_to_nodemask(unsigned long *p_nodes) +{ + struct memory_initiator *initiator; + + if (list_empty(&initiators)) + return -ENXIO; + + list_for_each_entry(initiator, &initiators, node) + set_bit(initiator->processor_pxm, p_nodes); + + return 0; +} + static void hmat_register_target_initiators(struct memory_target *target) { static DECLARE_BITMAP(p_nodes, MAX_NUMNODES); @@ -609,7 +618,10 @@ static void hmat_register_target_initiators(struct memory_target *target) * initiators. */ bitmap_zero(p_nodes, MAX_NUMNODES); - list_sort(p_nodes, &initiators, initiator_cmp); + list_sort(NULL, &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 +655,9 @@ 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)