[tip: x86/cache] x86/resctrl: Move default group file creation to mount

From: tip-bot2 for Babu Moger
Date: Tue Oct 17 2023 - 08:18:16 EST


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

Commit-ID: d27567a0eb54be457b25e240593fdbd1c35c8618
Gitweb: https://git.kernel.org/tip/d27567a0eb54be457b25e240593fdbd1c35c8618
Author: Babu Moger <babu.moger@xxxxxxx>
AuthorDate: Mon, 16 Oct 2023 19:23:04 -05:00
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Tue, 17 Oct 2023 12:50:53 +02:00

x86/resctrl: Move default group file creation to mount

The default resource group and its files are created during kernel init
time. Upcoming changes will make some resctrl files optional based on
a mount parameter. If optional files are to be added to the default
group based on the mount option, then each new file needs to be created
separately and call kernfs_activate() again.

Create all files of the default resource group during resctrl mount,
destroyed during unmount, to avoid scattering resctrl file addition
across two separate code flows.

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Peter Newman <peternewman@xxxxxxxxxx>
Reviewed-by: Tan Shaopeng <tan.shaopeng@xxxxxxxxxxxxxx>
Reviewed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Tested-by: Peter Newman <peternewman@xxxxxxxxxx>
Tested-by: Tan Shaopeng <tan.shaopeng@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231017002308.134480-6-babu.moger@xxxxxxx
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 58 ++++++++++++++-----------
1 file changed, 34 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index d1b5fd7..55da93b 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -54,6 +54,9 @@ static struct kernfs_node *kn_mondata;
static struct seq_buf last_cmd_status;
static char last_cmd_status_buf[512];

+static int rdtgroup_setup_root(struct rdt_fs_context *ctx);
+static void rdtgroup_destroy_root(void);
+
struct dentry *debugfs_resctrl;

void rdt_last_cmd_clear(void)
@@ -2529,10 +2532,14 @@ static int rdt_get_tree(struct fs_context *fc)
goto out;
}

- ret = rdt_enable_ctx(ctx);
+ ret = rdtgroup_setup_root(ctx);
if (ret)
goto out;

+ ret = rdt_enable_ctx(ctx);
+ if (ret)
+ goto out_root;
+
ret = schemata_list_create();
if (ret) {
schemata_list_destroy();
@@ -2541,6 +2548,12 @@ static int rdt_get_tree(struct fs_context *fc)

closid_init();

+ ret = rdtgroup_add_files(rdtgroup_default.kn, RFTYPE_CTRL_BASE);
+ if (ret)
+ goto out_schemata_free;
+
+ kernfs_activate(rdtgroup_default.kn);
+
ret = rdtgroup_create_info_dir(rdtgroup_default.kn);
if (ret < 0)
goto out_schemata_free;
@@ -2597,6 +2610,8 @@ out_schemata_free:
schemata_list_destroy();
out_ctx:
rdt_disable_ctx();
+out_root:
+ rdtgroup_destroy_root();
out:
rdt_last_cmd_clear();
mutex_unlock(&rdtgroup_mutex);
@@ -2667,7 +2682,6 @@ static int rdt_init_fs_context(struct fs_context *fc)
if (!ctx)
return -ENOMEM;

- ctx->kfc.root = rdt_root;
ctx->kfc.magic = RDTGROUP_SUPER_MAGIC;
fc->fs_private = &ctx->kfc;
fc->ops = &rdt_fs_context_ops;
@@ -2837,6 +2851,7 @@ static void rdt_kill_sb(struct super_block *sb)
rdt_pseudo_lock_release();
rdtgroup_default.mode = RDT_MODE_SHAREABLE;
schemata_list_destroy();
+ rdtgroup_destroy_root();
static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
static_branch_disable_cpuslocked(&rdt_mon_enable_key);
static_branch_disable_cpuslocked(&rdt_enable_key);
@@ -3718,10 +3733,8 @@ static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {
.show_options = rdtgroup_show_options,
};

-static int __init rdtgroup_setup_root(void)
+static int rdtgroup_setup_root(struct rdt_fs_context *ctx)
{
- int ret;
-
rdt_root = kernfs_create_root(&rdtgroup_kf_syscall_ops,
KERNFS_ROOT_CREATE_DEACTIVATED |
KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK,
@@ -3729,6 +3742,20 @@ static int __init rdtgroup_setup_root(void)
if (IS_ERR(rdt_root))
return PTR_ERR(rdt_root);

+ ctx->kfc.root = rdt_root;
+ rdtgroup_default.kn = kernfs_root_to_node(rdt_root);
+
+ return 0;
+}
+
+static void rdtgroup_destroy_root(void)
+{
+ kernfs_destroy_root(rdt_root);
+ rdtgroup_default.kn = NULL;
+}
+
+static void __init rdtgroup_setup_default(void)
+{
mutex_lock(&rdtgroup_mutex);

rdtgroup_default.closid = 0;
@@ -3738,19 +3765,7 @@ static int __init rdtgroup_setup_root(void)

list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);

- ret = rdtgroup_add_files(kernfs_root_to_node(rdt_root), RFTYPE_CTRL_BASE);
- if (ret) {
- kernfs_destroy_root(rdt_root);
- goto out;
- }
-
- rdtgroup_default.kn = kernfs_root_to_node(rdt_root);
- kernfs_activate(rdtgroup_default.kn);
-
-out:
mutex_unlock(&rdtgroup_mutex);
-
- return ret;
}

static void domain_destroy_mon_state(struct rdt_domain *d)
@@ -3872,13 +3887,11 @@ int __init rdtgroup_init(void)
seq_buf_init(&last_cmd_status, last_cmd_status_buf,
sizeof(last_cmd_status_buf));

- ret = rdtgroup_setup_root();
- if (ret)
- return ret;
+ rdtgroup_setup_default();

ret = sysfs_create_mount_point(fs_kobj, "resctrl");
if (ret)
- goto cleanup_root;
+ return ret;

ret = register_filesystem(&rdt_fs_type);
if (ret)
@@ -3911,8 +3924,6 @@ int __init rdtgroup_init(void)

cleanup_mountpoint:
sysfs_remove_mount_point(fs_kobj, "resctrl");
-cleanup_root:
- kernfs_destroy_root(rdt_root);

return ret;
}
@@ -3922,5 +3933,4 @@ void __exit rdtgroup_exit(void)
debugfs_remove_recursive(debugfs_resctrl);
unregister_filesystem(&rdt_fs_type);
sysfs_remove_mount_point(fs_kobj, "resctrl");
- kernfs_destroy_root(rdt_root);
}