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Commit 716f479d authored by Tejun Heo's avatar Tejun Heo
Browse files

hugetlb_cgroup: convert away from cftype->read() 



In preparation of conversion to kernfs, cgroup file handling is being
consolidated so that it can be easily mapped to the seq_file based
interface of kernfs.

All users of cftype->read() can be easily served, usually better, by
seq_file and other methods.  Update hugetlb_cgroup_read() to return
u64 instead of printing itself and rename it to
hugetlb_cgroup_read_u64().

This patch doesn't make any visible behavior changes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
parent e92e113c

mm/hugetlb_cgroup.c

+8 −14
Original line number Diff line number Diff line
@@ -242,22 +242,16 @@ void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, 
	return;

}



static ssize_t hugetlb_cgroup_read(struct cgroup_subsys_state *css,

				   struct cftype *cft, struct file *file,

				   char __user *buf, size_t nbytes,

				   loff_t *ppos)

static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,

				   struct cftype *cft)

{

	u64 val;

	char str[64];

	int idx, name, len;

	int idx, name;

	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);



	idx = MEMFILE_IDX(cft->private);

	name = MEMFILE_ATTR(cft->private);



	val = res_counter_read_u64(&h_cg->hugepage[idx], name);

	len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);

	return simple_read_from_buffer(buf, nbytes, ppos, str, len);

	return res_counter_read_u64(&h_cg->hugepage[idx], name);

}



static int hugetlb_cgroup_write(struct cgroup_subsys_state *css,
@@ -337,28 +331,28 @@ static void __init __hugetlb_cgroup_file_init(int idx) 
	cft = &h->cgroup_files[0];

	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);

	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);

	cft->read = hugetlb_cgroup_read;

	cft->read_u64 = hugetlb_cgroup_read_u64;

	cft->write_string = hugetlb_cgroup_write;



	/* Add the usage file */

	cft = &h->cgroup_files[1];

	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);

	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);

	cft->read = hugetlb_cgroup_read;

	cft->read_u64 = hugetlb_cgroup_read_u64;



	/* Add the MAX usage file */

	cft = &h->cgroup_files[2];

	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);

	cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);

	cft->trigger = hugetlb_cgroup_reset;

	cft->read = hugetlb_cgroup_read;

	cft->read_u64 = hugetlb_cgroup_read_u64;



	/* Add the failcntfile */

	cft = &h->cgroup_files[3];

	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);

	cft->private  = MEMFILE_PRIVATE(idx, RES_FAILCNT);

	cft->trigger  = hugetlb_cgroup_reset;

	cft->read = hugetlb_cgroup_read;

	cft->read_u64 = hugetlb_cgroup_read_u64;



	/* NULL terminate the last cft */

	cft = &h->cgroup_files[4];