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From:   Kristen Carlson Accardi <kristen@linux.intel.com>
To:     jarkko@kernel.org, dave.hansen@linux.kernel.org, tj@kernel.org,
        linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org,
        cgroups@vger.kernel.org, Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>
Cc:     zhiquan1.li@intel.com,
        Kristen Carlson Accardi <kristen@linux.intel.com>
Subject: [PATCH 18/26] cgroup/misc: Expose root_misc
Date:   Fri, 11 Nov 2022 10:35:23 -0800
Message-Id: <20221111183532.3676646-19-kristen@linux.intel.com>
In-Reply-To: <20221111183532.3676646-1-kristen@linux.intel.com>
References: <20221111183532.3676646-1-kristen@linux.intel.com>
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The SGX driver will need to get access to the root misc_cg object
to do iterative walks and also determine if a charge will be
towards the root cgroup or not.

Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
---
 include/linux/misc_cgroup.h | 5 +++++
 kernel/cgroup/misc.c        | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/include/linux/misc_cgroup.h b/include/linux/misc_cgroup.h
index 8f1b7b6cb81d..b79c78378f17 100644
--- a/include/linux/misc_cgroup.h
+++ b/include/linux/misc_cgroup.h
@@ -59,6 +59,7 @@ struct misc_cg {
 	struct misc_res res[MISC_CG_RES_TYPES];
 };
 
+struct misc_cg *root_misc(void);
 unsigned long misc_cg_res_total_usage(enum misc_res_type type);
 int misc_cg_set_capacity(enum misc_res_type type, unsigned long capacity);
 int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
@@ -106,6 +107,10 @@ static inline void put_misc_cg(struct misc_cg *cg)
 }
 
 #else /* !CONFIG_CGROUP_MISC */
+static inline struct misc_cg *root_misc(void)
+{
+	return NULL;
+}
 
 static inline unsigned long misc_cg_res_total_usage(enum misc_res_type type)
 {
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
index 1e93e1d20347..8aa994d9cd02 100644
--- a/kernel/cgroup/misc.c
+++ b/kernel/cgroup/misc.c
@@ -45,6 +45,15 @@ static unsigned long misc_res_capacity[MISC_CG_RES_TYPES];
  */
 static BLOCKING_NOTIFIER_HEAD(misc_cg_notify_list);
 
+/**
+ * root_misc() - Return the root misc cgroup.
+ */
+struct misc_cg *root_misc(void)
+{
+	return &root_cg;
+}
+EXPORT_SYMBOL_GPL(root_misc);
+
 /**
  * parent_misc() - Get the parent of the passed misc cgroup.
  * @cgroup: cgroup whose parent needs to be fetched.
-- 
2.37.3