cgroup/cpuset: Move procfs cpuset attribute under cgroup-v1.c

The cpuset file is a legacy attribute that is bound primarily to cpuset
v1 hierarchy (equivalent information is available in /proc/$pid/cgroup path
on the unified hierarchy in conjunction with respective
cgroup.controllers showing where cpuset controller is enabled).

Followup to commit b0ced9d378d49 ("cgroup/cpuset: move v1 interfaces to
cpuset-v1.c") and hide CONFIG_PROC_PID_CPUSET under CONFIG_CPUSETS_V1.
Drop an obsolete comment too.

Signed-off-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/init/Kconfig b/init/Kconfig
index a20e6efd3f0fbdd7f0df2448854cc30734a0ee4f..2f3121c49ed232ad08bf9172c8b3a5c95da07dda 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1182,7 +1182,8 @@ config CPUSETS_V1
        help
          Legacy cgroup v1 cpusets controller which has been deprecated by
          cgroup v2 implementation. The v1 is there for legacy applications
-         which haven't migrated to the new cgroup v2 interface yet. If you
+         which haven't migrated to the new cgroup v2 interface yet. Legacy
+         interface includes cpuset filesystem and /proc/<pid>/cpuset. If you
          do not have any such application then you are completely fine leaving
          this option disabled.
 
@@ -1190,7 +1191,7 @@ config CPUSETS_V1
 
 config PROC_PID_CPUSET
        bool "Include legacy /proc/<pid>/cpuset file"
-       depends on CPUSETS
+       depends on CPUSETS_V1
        default y
 
 config CGROUP_DEVICE

diff --git a/kernel/cgroup/cpuset-v1.c b/kernel/cgroup/cpuset-v1.c
index 25c1d7b77e2f2aedeaaef3ebed8c4e03b668c213..81b5e2a50d587f1b99a6f553b4e0b8430d3207d6 100644 (file)
--- a/kernel/cgroup/cpuset-v1.c
+++ b/kernel/cgroup/cpuset-v1.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include "cgroup-internal.h"
 #include "cpuset-internal.h"
 
 /*
@@ -373,6 +374,46 @@ out:
        return ret;
 }
 
+#ifdef CONFIG_PROC_PID_CPUSET
+/*
+ * proc_cpuset_show()
+ *  - Print tasks cpuset path into seq_file.
+ *  - Used for /proc/<pid>/cpuset.
+ */
+int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
+                    struct pid *pid, struct task_struct *tsk)
+{
+       char *buf;
+       struct cgroup_subsys_state *css;
+       int retval;
+
+       retval = -ENOMEM;
+       buf = kmalloc(PATH_MAX, GFP_KERNEL);
+       if (!buf)
+               goto out;
+
+       rcu_read_lock();
+       spin_lock_irq(&css_set_lock);
+       css = task_css(tsk, cpuset_cgrp_id);
+       retval = cgroup_path_ns_locked(css->cgroup, buf, PATH_MAX,
+                                      current->nsproxy->cgroup_ns);
+       spin_unlock_irq(&css_set_lock);
+       rcu_read_unlock();
+
+       if (retval == -E2BIG)
+               retval = -ENAMETOOLONG;
+       if (retval < 0)
+               goto out_free;
+       seq_puts(m, buf);
+       seq_putc(m, '\n');
+       retval = 0;
+out_free:
+       kfree(buf);
+out:
+       return retval;
+}
+#endif /* CONFIG_PROC_PID_CPUSET */
+
 static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
 {
        struct cpuset *cs = css_cs(css);

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 0f910c828973a9a2c026f37e5a504b2ff538bd8d..5a637292faa2061dcd4293fd77b1e36c70f8f133 100644 (file)
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -21,7 +21,6 @@
  *  License.  See the file COPYING in the main directory of the Linux
  *  distribution for more details.
  */
-#include "cgroup-internal.h"
 #include "cpuset-internal.h"
 
 #include <linux/init.h>
@@ -4244,50 +4243,6 @@ void cpuset_print_current_mems_allowed(void)
        rcu_read_unlock();
 }
 
-#ifdef CONFIG_PROC_PID_CPUSET
-/*
- * proc_cpuset_show()
- *  - Print tasks cpuset path into seq_file.
- *  - Used for /proc/<pid>/cpuset.
- *  - No need to task_lock(tsk) on this tsk->cpuset reference, as it
- *    doesn't really matter if tsk->cpuset changes after we read it,
- *    and we take cpuset_mutex, keeping cpuset_attach() from changing it
- *    anyway.
- */
-int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
-                    struct pid *pid, struct task_struct *tsk)
-{
-       char *buf;
-       struct cgroup_subsys_state *css;
-       int retval;
-
-       retval = -ENOMEM;
-       buf = kmalloc(PATH_MAX, GFP_KERNEL);
-       if (!buf)
-               goto out;
-
-       rcu_read_lock();
-       spin_lock_irq(&css_set_lock);
-       css = task_css(tsk, cpuset_cgrp_id);
-       retval = cgroup_path_ns_locked(css->cgroup, buf, PATH_MAX,
-                                      current->nsproxy->cgroup_ns);
-       spin_unlock_irq(&css_set_lock);
-       rcu_read_unlock();
-
-       if (retval == -E2BIG)
-               retval = -ENAMETOOLONG;
-       if (retval < 0)
-               goto out_free;
-       seq_puts(m, buf);
-       seq_putc(m, '\n');
-       retval = 0;
-out_free:
-       kfree(buf);
-out:
-       return retval;
-}
-#endif /* CONFIG_PROC_PID_CPUSET */
-
 /* Display task mems_allowed in /proc/<pid>/status file. */
 void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
 {