linux-kernel - [PATCH v13 25/27] x86/resctrl: Hide the BMEC related files when mbm_cnt

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Message-ID: <1f86fadfa4fa0cb7daae506a8b0c22c1c3632ddd.1747349530.git.babu.moger@amd.com>
Date: Thu, 15 May 2025 17:52:10 -0500
From: Babu Moger <babu.moger@....com>
To: <corbet@....net>, <tony.luck@...el.com>, <reinette.chatre@...el.com>,
	<tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>
CC: <james.morse@....com>, <dave.martin@....com>, <fenghuay@...dia.com>,
	<x86@...nel.org>, <hpa@...or.com>, <paulmck@...nel.org>,
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	<ardb@...nel.org>, <gregkh@...uxfoundation.org>,
	<daniel.sneddon@...ux.intel.com>, <jpoimboe@...nel.org>,
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	<thomas.lendacky@....com>, <perry.yuan@....com>, <seanjc@...gle.com>,
	<kai.huang@...el.com>, <xiaoyao.li@...el.com>, <babu.moger@....com>,
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	<maciej.wieczor-retman@...el.com>, <eranian@...gle.com>,
	<Xiaojian.Du@....com>, <gautham.shenoy@....com>
Subject: [PATCH v13 25/27] x86/resctrl: Hide the BMEC related files when mbm_cnt_assign is enabled

BMEC (Bandwidth Monitoring Event Configuration) and mbm_cntr_assign cannot
be used simultaneously.

When mbm_cntr_assign is active, suppress visibility of BMEC-related files
to prevent confusion.

The files /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config and
/sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config will not be visible
when mbm_cntr_assign mode is enabled.

Suggested-by: Reinette Chatre <reinette.chatre@...el.com>
Signed-off-by: Babu Moger <babu.moger@....com>
---
v13: New patch to hide BMEC related files.
---
 fs/resctrl/rdtgroup.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index ea1782723f81..d6bf2a50a105 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1815,6 +1815,33 @@ static ssize_t mbm_local_bytes_config_write(struct kernfs_open_file *of,
 	return ret ?: nbytes;
 }
 
+static void resctrl_bmec_files_show(struct rdt_resource *r, bool show)
+{
+	struct kernfs_node *kn_config, *l3_mon_kn;
+	char name[32];
+
+	sprintf(name, "%s_MON", r->name);
+	l3_mon_kn = kernfs_find_and_get(kn_info, name);
+	if (!l3_mon_kn)
+		return;
+
+	kn_config = kernfs_find_and_get(l3_mon_kn, "mbm_total_bytes_config");
+	if (kn_config) {
+		kernfs_get(kn_config);
+		kernfs_show(kn_config, show);
+		kernfs_put(kn_config);
+	}
+
+	kn_config = kernfs_find_and_get(l3_mon_kn, "mbm_local_bytes_config");
+	if (kn_config) {
+		kernfs_get(kn_config);
+		kernfs_show(kn_config, show);
+		kernfs_put(kn_config);
+	}
+
+	kernfs_put(l3_mon_kn);
+}
+
 static int resctrl_mbm_assign_mode_show(struct kernfs_open_file *of,
 					struct seq_file *s, void *v)
 {
@@ -2815,6 +2842,10 @@ static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 			ret = resctrl_mkdir_counter_configs(r, name);
 			if (ret)
 				goto out_destroy;
+
+			/* Hide BMEC related files if mbm_cntr_assign is enabled */
+			if (resctrl_arch_mbm_cntr_assign_enabled(r))
+				resctrl_bmec_files_show(r, false);
 		}
 	}
 
-- 
2.34.1