FAILED: patch "[PATCH] x86/resctrl: Don't stop walking closids when a locksetup" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-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 <[email protected]>.

thanks,

greg k-h

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

From 87d3aa28f345bea77c396855fa5d5fec4c24461f Mon Sep 17 00:00:00 2001
From: James Morse <[email protected]>
Date: Mon, 3 Jun 2019 18:25:31 +0100
Subject: [PATCH] x86/resctrl: Don't stop walking closids when a locksetup
group is found

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.

index 333c177a2471..869cbef5da81 100644
@@ -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);
 			if (mode == RDT_MODE_PSEUDO_LOCKSETUP)
-				break;
+				/*
+				 * ctrl values for locksetup aren't relevant
+				 * until the schemata is written, and the mode
+				 * becomes RDT_MODE_PSEUDO_LOCKED.
+				 */
+				continue;
 			/*
 			 * If CDP is active include peer domain's
 			 * usage to ensure there is no overlap