Commit b1664924 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: introduce cgroup_ino() 



mm/memory-failure.c::hwpoison_filter_task() has been reaching into
cgroup to extract the associated ino to be used as a filtering
criterion.  This is an implementation detail which shouldn't be
depended upon from outside cgroup proper and is about to change with
the scheduled kernfs conversion.

This patch introduces a proper interface to determine the associated
ino, cgroup_ino(), and updates hwpoison_filter_task() to use it
instead of reaching directly into cgroup.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
parent 2da440a2

include/linux/cgroup.h

+9 −0
Original line number Diff line number Diff line
@@ -507,6 +507,15 @@ static inline const char *cgroup_name(const struct cgroup *cgrp) 
	return rcu_dereference(cgrp->name)->name;

}



/* returns ino associated with a cgroup, 0 indicates unmounted root */

static inline ino_t cgroup_ino(struct cgroup *cgrp)

{

	if (cgrp->dentry)

		return cgrp->dentry->d_inode->i_ino;

	else

		return 0;

}



static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)

{

	struct cgroup_open_file *of = seq->private;

kernel/cgroup.c

+4 −1
Original line number Diff line number Diff line
@@ -792,7 +792,10 @@ static struct inode *cgroup_new_inode(umode_t mode, struct super_block *sb) 
	struct inode *inode = new_inode(sb);



	if (inode) {

		do {

			/* ino 0 is reserved for dummy_root */

			inode->i_ino = get_next_ino();

		} while (!inode->i_ino);

		inode->i_mode = mode;

		inode->i_uid = current_fsuid();

		inode->i_gid = current_fsgid();

mm/memory-failure.c

+2 −6
Original line number Diff line number Diff line
@@ -145,14 +145,10 @@ static int hwpoison_filter_task(struct page *p) 
		return -EINVAL;



	css = mem_cgroup_css(mem);

	/* root_mem_cgroup has NULL dentries */

	if (!css->cgroup->dentry)

		return -EINVAL;



	ino = css->cgroup->dentry->d_inode->i_ino;

	ino = cgroup_ino(css->cgroup);

	css_put(css);



	if (ino != hwpoison_filter_memcg)

	if (!ino || ino != hwpoison_filter_memcg)

		return -EINVAL;



	return 0;

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