[PATCH v3 16/38] x86/resctrl: Move monitor init work to a resctrl init call

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

rdt_get_mon_l3_config() is called from the architecture's
resctrl_arch_late_init(), and initialises both architecture specific
fields, such as hw_res->mon_scale and resctrl filesystem fields
by calling dom_data_init().

To separate the filesystem and architecture parts of resctrl, this
function needs splitting up.

Add resctrl_mon_resource_init() to do the filesystem specific work,
and call it from resctrl_init(). This runs later, but is still before
the filesystem is mounted and the rmid_ptrs[] array can be used.

Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
---
Changes since v2:
 * Added error handling for the case sysfs files can't be created.
---
 arch/x86/kernel/cpu/resctrl/internal.h |  1 +
 arch/x86/kernel/cpu/resctrl/monitor.c  | 24 +++++++++++++++++-------
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |  9 ++++++++-
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 9aa7f587484c..eaf458967fa1 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -542,6 +542,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg);
 void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
 		    struct rdt_domain *d, struct rdtgroup *rdtgrp,
 		    int evtid, int first);
+int resctrl_mon_resource_init(void);
 void mbm_setup_overflow_handler(struct rdt_domain *dom,
 				unsigned long delay_ms,
 				int exclude_cpu);
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 7d6aebce75c1..527c0e9d7b2e 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -1016,12 +1016,28 @@ static void l3_mon_evt_init(struct rdt_resource *r)
 		list_add_tail(&mbm_local_event.list, &r->evt_list);
 }
 
+int resctrl_mon_resource_init(void)
+{
+	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
+	int ret;
+
+	if (!r->mon_capable)
+		return 0;
+
+	ret = dom_data_init(r);
+	if (ret)
+		return ret;
+
+	l3_mon_evt_init(r);
+
+	return 0;
+}
+
 int __init rdt_get_mon_l3_config(struct rdt_resource *r)
 {
 	unsigned int mbm_offset = boot_cpu_data.x86_cache_mbm_width_offset;
 	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
 	unsigned int threshold;
-	int ret;
 
 	resctrl_rmid_realloc_limit = boot_cpu_data.x86_cache_size * 1024;
 	hw_res->mon_scale = boot_cpu_data.x86_cache_occ_scale;
@@ -1049,10 +1065,6 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
 	 */
 	resctrl_rmid_realloc_threshold = resctrl_arch_round_mon_val(threshold);
 
-	ret = dom_data_init(r);
-	if (ret)
-		return ret;
-
 	if (rdt_cpu_has(X86_FEATURE_BMEC)) {
 		u32 eax, ebx, ecx, edx;
 
@@ -1070,8 +1082,6 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
 		}
 	}
 
-	l3_mon_evt_init(r);
-
 	r->mon_capable = true;
 
 	return 0;
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 8c380f389b93..9c03e973a5f6 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -4168,9 +4168,15 @@ int __init resctrl_init(void)
 
 	rdtgroup_setup_default();
 
+	ret = resctrl_mon_resource_init();
+	if (ret)
+		return ret;
+
 	ret = sysfs_create_mount_point(fs_kobj, "resctrl");
-	if (ret)
+	if (ret) {
+		resctrl_mon_resource_exit();
 		return ret;
+	}
 
 	ret = register_filesystem(&rdt_fs_type);
 	if (ret)
@@ -4203,6 +4209,7 @@ int __init resctrl_init(void)
 
 cleanup_mountpoint:
 	sysfs_remove_mount_point(fs_kobj, "resctrl");
+	resctrl_mon_resource_exit();
 
 	return ret;
 }
-- 
2.39.2