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, 8 insertions, 7 deletions

diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
index 841fd3fa937a..f7a2ec3ac584 100644
--- a/net/ipv4/tcp_memcontrol.c
+++ b/net/ipv4/tcp_memcontrol.c
@@ -170,17 +170,18 @@ static u64 tcp_cgroup_read(struct cgroup_subsys_state *css, struct cftype *cft)
         return val;
 }
 
-static int tcp_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)
+static ssize_t tcp_cgroup_reset(struct kernfs_open_file *of,
+                                char *buf, size_t nbytes, loff_t off)
 {
         struct mem_cgroup *memcg;
         struct cg_proto *cg_proto;
 
-        memcg = mem_cgroup_from_css(css);
+        memcg = mem_cgroup_from_css(of_css(of));
         cg_proto = tcp_prot.proto_cgroup(memcg);
         if (!cg_proto)
-                return 0;
+                return nbytes;
 
-        switch (event) {
+        switch (of_cft(of)->private) {
         case RES_MAX_USAGE:
                 res_counter_reset_max(&cg_proto->memory_allocated);
                 break;
@@ -189,7 +190,7 @@ static int tcp_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)
                 break;
         }
 
-        return 0;
+        return nbytes;
 }
 
 static struct cftype tcp_files[] = {
@@ -207,13 +208,13 @@ static struct cftype tcp_files[] = {
         {
                 .name = "kmem.tcp.failcnt",
                 .private = RES_FAILCNT,
-                .trigger = tcp_cgroup_reset,
+                .write = tcp_cgroup_reset,
                 .read_u64 = tcp_cgroup_read,
         },
         {
                 .name = "kmem.tcp.max_usage_in_bytes",
                 .private = RES_MAX_USAGE,
-                .trigger = tcp_cgroup_reset,
+                .write = tcp_cgroup_reset,
                 .read_u64 = tcp_cgroup_read,
         },
         { }     /* terminate */