cgroup: replace cftype->trigger() with cftype->write()

cftype->trigger() is pointless.  It's trivial to ignore the input
buffer from a regular ->write() operation.  Convert all ->trigger()
users to ->write() and remove ->trigger().

This patch doesn't introduce any visible behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>

1 files changed, 1 insertions, 4 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2a88ce7b24b6..2f16aab03493 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1034,8 +1034,7 @@ static umode_t cgroup_file_mode(const struct cftype *cft)
         if (cft->read_u64 || cft->read_s64 || cft->seq_show)
                 mode |= S_IRUGO;
 
-        if (cft->write_u64 || cft->write_s64 || cft->write ||
-            cft->trigger)
+        if (cft->write_u64 || cft->write_s64 || cft->write)
                 mode |= S_IWUSR;
 
         return mode;
@@ -2750,8 +2749,6 @@ static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf,
                 ret = kstrtoll(buf, 0, &v);
                 if (!ret)
                         ret = cft->write_s64(css, cft, v);
-        } else if (cft->trigger) {
-                ret = cft->trigger(css, (unsigned int)cft->private);
         } else {
                 ret = -EINVAL;
         }