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Commit 59735bfc authored by Tejun Heo's avatar Tejun Heo Committed by Suren Baghdasaryan
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UPSTREAM: cgroup add cftype->open/release() callbacks 



Pipe the newly added kernfs->open/release() callbacks through cftype.
While at it, as cleanup operations now can be performed from
->release() instead of ->seq_stop(), make the latter optional.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarAcked-by: Zefan Li <lizefan@huawei.com>

(cherry picked from commit e90cbebc3fa5caea4c8bfeb0d0157a0cee53efc7)

Bug: 111308141
Test: modified lmkd to use PSI and tested using lmkd_unit_test

Change-Id: Iff9794cbbc2c7067c24cb2f767bbdeffa26b5180
Signed-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
parent 1325e703

include/linux/cgroup-defs.h

+3 −0
Original line number Diff line number Diff line
@@ -393,6 +393,9 @@ struct cftype { 
	struct list_head node;		/* anchored at ss->cfts */

	struct kernfs_ops *kf_ops;



	int (*open)(struct kernfs_open_file *of);

	void (*release)(struct kernfs_open_file *of);



	/*

	 * read_u64() is a shortcut for the common case of returning a

	 * single integer. Use it in place of read()

kernel/cgroup.c

+23 −1
Original line number Diff line number Diff line
@@ -3501,6 +3501,23 @@ static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v) 
}

#endif



static int cgroup_file_open(struct kernfs_open_file *of)

{

	struct cftype *cft = of->kn->priv;



	if (cft->open)

		return cft->open(of);

	return 0;

}



static void cgroup_file_release(struct kernfs_open_file *of)

{

	struct cftype *cft = of->kn->priv;



	if (cft->release)

		cft->release(of);

}



static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf,

				 size_t nbytes, loff_t off)

{
@@ -3551,6 +3568,7 @@ static void *cgroup_seqfile_next(struct seq_file *seq, void *v, loff_t *ppos) 


static void cgroup_seqfile_stop(struct seq_file *seq, void *v)

{

	if (seq_cft(seq)->seq_stop)

		seq_cft(seq)->seq_stop(seq, v);

}
@@ -3573,12 +3591,16 @@ static int cgroup_seqfile_show(struct seq_file *m, void *arg) 


static struct kernfs_ops cgroup_kf_single_ops = {

	.atomic_write_len	= PAGE_SIZE,

	.open			= cgroup_file_open,

	.release		= cgroup_file_release,

	.write			= cgroup_file_write,

	.seq_show		= cgroup_seqfile_show,

};



static struct kernfs_ops cgroup_kf_ops = {

	.atomic_write_len	= PAGE_SIZE,

	.open			= cgroup_file_open,

	.release		= cgroup_file_release,

	.write			= cgroup_file_write,

	.seq_start		= cgroup_seqfile_start,

	.seq_next		= cgroup_seqfile_next,