[RFC PATCH 03/20] x86/intel_rdt: Group staged configuration into a separate struct

[James Morse <james.morse@arm.com>]

We want to merge the L2/L2CODE/L2DATA resources to be a single resource,
but we still need to be able to apply separate CODE and DATA schema to
the domain.

Move the new_ctrl bitmap value and flag into a struct, and create an
array of them. Today there is only one element in the array, but
eventually resctrl will use the array slots for CODE/DATA/BOTH to
detect a duplicate schema being written.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c | 44 +++++++++++++++------
 include/linux/resctrl.h                     | 16 ++++++--
 2 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
index e3dcb5161122..1068a19e03c5 100644
--- a/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
+++ b/arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c
@@ -67,16 +67,17 @@ static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
 int parse_bw(char *buf, struct rdt_resource *r, struct rdt_domain *d)
 {
 	unsigned long data;
+	struct resctrl_staged_config *cfg = &d->staged_config[0];
 
-	if (d->have_new_ctrl) {
+	if (cfg->have_new_ctrl) {
 		rdt_last_cmd_printf("duplicate domain %d\n", d->id);
 		return -EINVAL;
 	}
 
 	if (!bw_validate(buf, &data, r))
 		return -EINVAL;
-	d->new_ctrl = data;
-	d->have_new_ctrl = true;
+	cfg->new_ctrl = data;
+	cfg->have_new_ctrl = true;
 
 	return 0;
 }
@@ -129,16 +130,17 @@ static bool cbm_validate(char *buf, unsigned long *data, struct rdt_resource *r)
 int parse_cbm(char *buf, struct rdt_resource *r, struct rdt_domain *d)
 {
 	unsigned long data;
+	struct resctrl_staged_config *cfg = &d->staged_config[0];
 
-	if (d->have_new_ctrl) {
+	if (cfg->have_new_ctrl) {
 		rdt_last_cmd_printf("duplicate domain %d\n", d->id);
 		return -EINVAL;
 	}
 
 	if(!cbm_validate(buf, &data, r))
 		return -EINVAL;
-	d->new_ctrl = data;
-	d->have_new_ctrl = true;
+	cfg->new_ctrl = data;
+	cfg->have_new_ctrl = true;
 
 	return 0;
 }
@@ -175,15 +177,29 @@ static int parse_line(char *line, struct rdt_resource *r)
 	return -EINVAL;
 }
 
+static void apply_config(struct rdt_hw_domain *hw_dom,
+			 struct resctrl_staged_config *cfg, int closid,
+			 cpumask_var_t cpu_mask, bool mba_sc)
+{
+	u32 *dc = !mba_sc ? hw_dom->ctrl_val : hw_dom->mbps_val;
+
+	if (cfg->new_ctrl != dc[closid]) {
+		cpumask_set_cpu(cpumask_any(&hw_dom->resctrl.cpu_mask),
+				cpu_mask);
+		dc[closid] = cfg->new_ctrl;
+		cfg->have_new_ctrl = false;
+	}
+}
+
 static int update_domains(struct rdt_resource *r, int closid)
 {
+	struct resctrl_staged_config *cfg;
 	struct rdt_hw_domain *hw_dom;
 	struct msr_param msr_param;
 	cpumask_var_t cpu_mask;
 	struct rdt_domain *d;
 	bool mba_sc;
-	u32 *dc;
-	int cpu;
+	int i, cpu;
 
 	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
 		return -ENOMEM;
@@ -195,10 +211,12 @@ static int update_domains(struct rdt_resource *r, int closid)
 	mba_sc = is_mba_sc(r);
 	list_for_each_entry(d, &r->domains, list) {
 		hw_dom = rc_dom_to_rdt(d);
-		dc = !mba_sc ? hw_dom->ctrl_val : hw_dom->mbps_val;
-		if (d->have_new_ctrl && d->new_ctrl != dc[closid]) {
-			cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
-			dc[closid] = d->new_ctrl;
+		for (i = 0; i < ARRAY_SIZE(d->staged_config); i++) {
+			cfg = &hw_dom->resctrl.staged_config[i];
+			if (!cfg->have_new_ctrl)
+				continue;
+
+			apply_config(hw_dom, cfg, closid, cpu_mask, mba_sc);
 		}
 	}
 
@@ -259,7 +277,7 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
 
 	for_each_alloc_enabled_rdt_resource(r) {
 		list_for_each_entry(dom, &r->domains, list)
-			dom->have_new_ctrl = false;
+			memset(dom->staged_config, 0, sizeof(dom->staged_config));
 	}
 
 	while ((tok = strsep(&buf, "\n")) != NULL) {
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 5950c30fcc30..0b57a55f4b3d 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -7,21 +7,29 @@
 #include <linux/list.h>
 #include <linux/kernel.h>
 
+/**
+ * struct resctrl_staged_config - parsed configuration to be applied
+ * @new_ctrl:		new ctrl value to be loaded
+ * @have_new_ctrl:	did user provide new_ctrl for this domain
+ */
+struct resctrl_staged_config {
+	u32			new_ctrl;
+	bool			have_new_ctrl;
+};
+
 /**
  * struct rdt_domain - group of cpus sharing an RDT resource
  * @list:	all instances of this resource
  * @id:		unique id for this instance
  * @cpu_mask:	which cpus share this resource
- * @new_ctrl:	new ctrl value to be loaded
- * @have_new_ctrl: did user provide new_ctrl for this domain
+ * @staged_config: parsed configuration to be applied
  */
 struct rdt_domain {
 	struct list_head	list;
 	int			id;
 	struct cpumask		cpu_mask;
 
-	u32			new_ctrl;
-	bool			have_new_ctrl;
+	struct resctrl_staged_config	staged_config[1];
 };
 
 /**
-- 
2.18.0