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>

1 files changed, 15 insertions, 20 deletions

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 06534049afba..a760857e6b62 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1303,13 +1303,10 @@ static u64 tg_prfill_cpu_rwstat(struct seq_file *sf,
         return __blkg_prfill_rwstat(sf, pd, &rwstat);
 }
 
-static int tg_print_cpu_rwstat(struct cgroup_subsys_state *css,
-                               struct cftype *cft, struct seq_file *sf)
+static int tg_print_cpu_rwstat(struct seq_file *sf, void *v)
 {
-        struct blkcg *blkcg = css_to_blkcg(css);
-
-        blkcg_print_blkgs(sf, blkcg, tg_prfill_cpu_rwstat, &blkcg_policy_throtl,
-                          cft->private, true);
+        blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_cpu_rwstat,
+                          &blkcg_policy_throtl, seq_cft(sf)->private, true);
         return 0;
 }
 
@@ -1335,19 +1332,17 @@ static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd,
         return __blkg_prfill_u64(sf, pd, v);
 }
 
-static int tg_print_conf_u64(struct cgroup_subsys_state *css,
-                             struct cftype *cft, struct seq_file *sf)
+static int tg_print_conf_u64(struct seq_file *sf, void *v)
 {
-        blkcg_print_blkgs(sf, css_to_blkcg(css), tg_prfill_conf_u64,
-                          &blkcg_policy_throtl, cft->private, false);
+        blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_u64,
+                          &blkcg_policy_throtl, seq_cft(sf)->private, false);
         return 0;
 }
 
-static int tg_print_conf_uint(struct cgroup_subsys_state *css,
-                              struct cftype *cft, struct seq_file *sf)
+static int tg_print_conf_uint(struct seq_file *sf, void *v)
 {
-        blkcg_print_blkgs(sf, css_to_blkcg(css), tg_prfill_conf_uint,
-                          &blkcg_policy_throtl, cft->private, false);
+        blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_uint,
+                          &blkcg_policy_throtl, seq_cft(sf)->private, false);
         return 0;
 }
 
@@ -1428,40 +1423,40 @@ static struct cftype throtl_files[] = {
         {
                 .name = "throttle.read_bps_device",
                 .private = offsetof(struct throtl_grp, bps[READ]),
-                .read_seq_string = tg_print_conf_u64,
+                .seq_show = tg_print_conf_u64,
                 .write_string = tg_set_conf_u64,
                 .max_write_len = 256,
         },
         {
                 .name = "throttle.write_bps_device",
                 .private = offsetof(struct throtl_grp, bps[WRITE]),
-                .read_seq_string = tg_print_conf_u64,
+                .seq_show = tg_print_conf_u64,
                 .write_string = tg_set_conf_u64,
                 .max_write_len = 256,
         },
         {
                 .name = "throttle.read_iops_device",
                 .private = offsetof(struct throtl_grp, iops[READ]),
-                .read_seq_string = tg_print_conf_uint,
+                .seq_show = tg_print_conf_uint,
                 .write_string = tg_set_conf_uint,
                 .max_write_len = 256,
         },
         {
                 .name = "throttle.write_iops_device",
                 .private = offsetof(struct throtl_grp, iops[WRITE]),
-                .read_seq_string = tg_print_conf_uint,
+                .seq_show = tg_print_conf_uint,
                 .write_string = tg_set_conf_uint,
                 .max_write_len = 256,
         },
         {
                 .name = "throttle.io_service_bytes",
                 .private = offsetof(struct tg_stats_cpu, service_bytes),
-                .read_seq_string = tg_print_cpu_rwstat,
+                .seq_show = tg_print_cpu_rwstat,
         },
         {
                 .name = "throttle.io_serviced",
                 .private = offsetof(struct tg_stats_cpu, serviced),
-                .read_seq_string = tg_print_cpu_rwstat,
+                .seq_show = tg_print_cpu_rwstat,
         },
         { }     /* terminate */
 };