linux-kernel - [tip: x86/cache] x86/resctrl: Unwind properly from rdt_enable

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Date:   Tue, 17 Oct 2023 12:18:00 -0000
From:   "tip-bot2 for Babu Moger" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Reinette Chatre <reinette.chatre@...el.com>,
        Babu Moger <babu.moger@....com>,
        "Borislav Petkov (AMD)" <bp@...en8.de>,
        Peter Newman <peternewman@...gle.com>,
        Tan Shaopeng <tan.shaopeng@...fujitsu.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        ilpo.jarvinen@...ux.intel.com, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/cache] x86/resctrl: Unwind properly from rdt_enable_ctx()

The following commit has been merged into the x86/cache branch of tip:

Commit-ID:     df5f3a1dd8a6d3ddb1f07a10817f735194717422
Gitweb:        https://git.kernel.org/tip/df5f3a1dd8a6d3ddb1f07a10817f735194717422
Author:        Babu Moger <babu.moger@....com>
AuthorDate:    Mon, 16 Oct 2023 19:23:03 -05:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 17 Oct 2023 12:49:02 +02:00

x86/resctrl: Unwind properly from rdt_enable_ctx()

rdt_enable_ctx() enables the features provided during resctrl mount.

Additions to rdt_enable_ctx() are required to also modify error paths
of rdt_enable_ctx() callers to ensure correct unwinding if errors
are encountered after calling rdt_enable_ctx(). This is error prone.

Introduce rdt_disable_ctx() to refactor the error unwinding of
rdt_enable_ctx() to simplify future additions. This also simplifies
cleanup in rdt_kill_sb().

Suggested-by: Reinette Chatre <reinette.chatre@...el.com>
Signed-off-by: Babu Moger <babu.moger@....com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Peter Newman <peternewman@...gle.com>
Reviewed-by: Tan Shaopeng <tan.shaopeng@...fujitsu.com>
Reviewed-by: Fenghua Yu <fenghua.yu@...el.com>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Tested-by: Peter Newman <peternewman@...gle.com>
Tested-by: Tan Shaopeng <tan.shaopeng@...fujitsu.com>
Link: https://lore.kernel.org/r/20231017002308.134480-5-babu.moger@amd.com
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 53 +++++++++++++++----------
 1 file changed, 32 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 125d12d..d1b5fd7 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2308,14 +2308,6 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable)
 	return 0;
 }
 
-static void cdp_disable_all(void)
-{
-	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
-		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
-	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
-		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
-}
-
 /*
  * We don't allow rdtgroup directories to be created anywhere
  * except the root directory. Thus when looking for the rdtgroup
@@ -2395,19 +2387,42 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
 			     struct rdtgroup *prgrp,
 			     struct kernfs_node **mon_data_kn);
 
+static void rdt_disable_ctx(void)
+{
+	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
+	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
+	set_mba_sc(false);
+}
+
 static int rdt_enable_ctx(struct rdt_fs_context *ctx)
 {
 	int ret = 0;
 
-	if (ctx->enable_cdpl2)
+	if (ctx->enable_cdpl2) {
 		ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, true);
+		if (ret)
+			goto out_done;
+	}
 
-	if (!ret && ctx->enable_cdpl3)
+	if (ctx->enable_cdpl3) {
 		ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, true);
+		if (ret)
+			goto out_cdpl2;
+	}
 
-	if (!ret && ctx->enable_mba_mbps)
+	if (ctx->enable_mba_mbps) {
 		ret = set_mba_sc(true);
+		if (ret)
+			goto out_cdpl3;
+	}
+
+	return 0;
 
+out_cdpl3:
+	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
+out_cdpl2:
+	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
+out_done:
 	return ret;
 }
 
@@ -2515,13 +2530,13 @@ static int rdt_get_tree(struct fs_context *fc)
 	}
 
 	ret = rdt_enable_ctx(ctx);
-	if (ret < 0)
-		goto out_cdp;
+	if (ret)
+		goto out;
 
 	ret = schemata_list_create();
 	if (ret) {
 		schemata_list_destroy();
-		goto out_mba;
+		goto out_ctx;
 	}
 
 	closid_init();
@@ -2580,11 +2595,8 @@ out_info:
 	kernfs_remove(kn_info);
 out_schemata_free:
 	schemata_list_destroy();
-out_mba:
-	if (ctx->enable_mba_mbps)
-		set_mba_sc(false);
-out_cdp:
-	cdp_disable_all();
+out_ctx:
+	rdt_disable_ctx();
 out:
 	rdt_last_cmd_clear();
 	mutex_unlock(&rdtgroup_mutex);
@@ -2816,12 +2828,11 @@ static void rdt_kill_sb(struct super_block *sb)
 	cpus_read_lock();
 	mutex_lock(&rdtgroup_mutex);
 
-	set_mba_sc(false);
+	rdt_disable_ctx();
 
 	/*Put everything back to default values. */
 	for_each_alloc_capable_rdt_resource(r)
 		reset_all_ctrls(r);
-	cdp_disable_all();
 	rmdir_all_sub();
 	rdt_pseudo_lock_release();
 	rdtgroup_default.mode = RDT_MODE_SHAREABLE;