cgroup: replace cftype->read_seq_string() with cftype->seq_show()

In preparation of conversion to kernfs, cgroup file handling is
updated so that it can be easily mapped to kernfs.  This patch
replaces cftype->read_seq_string() with cftype->seq_show() which is
not limited to single_open() operation and will map directcly to
kernfs seq_file interface.

The conversions are mechanical.  As ->seq_show() doesn't have @css and
@cft, the functions which make use of them are converted to use
seq_css() and seq_cft() respectively.  In several occassions, e.f. if
it has seq_string in its name, the function name is updated to fit the
new method better.

This patch does not introduce any behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Aristeu Rozanski <arozansk@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Neil Horman <nhorman@tuxdriver.com>

2 files changed, 9 insertions, 12 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f28ec6722f0b..7e8cbb9ee4d6 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7256,10 +7256,9 @@ static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
 	return ret;
 }
 
-static int cpu_stats_show(struct cgroup_subsys_state *css, struct cftype *cft,
-			  struct seq_file *sf)
+static int cpu_stats_show(struct seq_file *sf, void *v)
 {
-	struct task_group *tg = css_tg(css);
+	struct task_group *tg = css_tg(seq_css(sf));
 	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
 
 	seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods);
@@ -7318,7 +7317,7 @@ static struct cftype cpu_files[] = {
 	},
 	{
 		.name = "stat",
-		.read_seq_string = cpu_stats_show,
+		.seq_show = cpu_stats_show,
 	},
 #endif
 #ifdef CONFIG_RT_GROUP_SCHED
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index dd88738cd4a9..622e0818f905 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -163,10 +163,9 @@ out:
 	return err;
 }
 
-static int cpuacct_percpu_seq_read(struct cgroup_subsys_state *css,
-				   struct cftype *cft, struct seq_file *m)
+static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
 {
-	struct cpuacct *ca = css_ca(css);
+	struct cpuacct *ca = css_ca(seq_css(m));
 	u64 percpu;
 	int i;
 
@@ -183,10 +182,9 @@ static const char * const cpuacct_stat_desc[] = {
 	[CPUACCT_STAT_SYSTEM] = "system",
 };
 
-static int cpuacct_stats_show(struct cgroup_subsys_state *css,
-			      struct cftype *cft, struct seq_file *sf)
+static int cpuacct_stats_show(struct seq_file *sf, void *v)
 {
-	struct cpuacct *ca = css_ca(css);
+	struct cpuacct *ca = css_ca(seq_css(sf));
 	int cpu;
 	s64 val = 0;
 
@@ -220,11 +218,11 @@ static struct cftype files[] = {
 	},
 	{
 		.name = "usage_percpu",
-		.read_seq_string = cpuacct_percpu_seq_read,
+		.seq_show = cpuacct_percpu_seq_show,
 	},
 	{
 		.name = "stat",
-		.read_seq_string = cpuacct_stats_show,
+		.seq_show = cpuacct_stats_show,
 	},
 	{ }	/* terminate */
 };