cgroup: replace cftype->write_string() with cftype->write()
Convert all cftype->write_string() users to the new cftype->write()
which maps directly to kernfs write operation and has full access to
kernfs and cgroup contexts. The conversions are mostly mechanical.
* @css and @cft are accessed using of_css() and of_cft() accessors
respectively instead of being specified as arguments.
* Should return @nbytes on success instead of 0.
* @buf is not trimmed automatically. Trim if necessary. Note that
blkcg and netprio don't need this as the parsers already handle
whitespaces.
cftype->write_string() has no user left after the conversions and
removed.
While at it, remove unnecessary local variable @p in
cgroup_subtree_control_write() and stale comment about
CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c.
This patch doesn't introduce any visible behavior changes.
v2: netprio was missing from conversion. Converted.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Aristeu Rozanski <arozansk@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5cf3246..7098a43 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5143,17 +5143,18 @@
* The user of this function is...
* RES_LIMIT.
*/
-static int mem_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft,
- char *buffer)
+static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
{
- struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
enum res_type type;
int name;
unsigned long long val;
int ret;
- type = MEMFILE_TYPE(cft->private);
- name = MEMFILE_ATTR(cft->private);
+ buf = strstrip(buf);
+ type = MEMFILE_TYPE(of_cft(of)->private);
+ name = MEMFILE_ATTR(of_cft(of)->private);
switch (name) {
case RES_LIMIT:
@@ -5162,7 +5163,7 @@
break;
}
/* This function does all necessary parse...reuse it */
- ret = res_counter_memparse_write_strategy(buffer, &val);
+ ret = res_counter_memparse_write_strategy(buf, &val);
if (ret)
break;
if (type == _MEM)
@@ -5175,7 +5176,7 @@
return -EINVAL;
break;
case RES_SOFT_LIMIT:
- ret = res_counter_memparse_write_strategy(buffer, &val);
+ ret = res_counter_memparse_write_strategy(buf, &val);
if (ret)
break;
/*
@@ -5192,7 +5193,7 @@
ret = -EINVAL; /* should be BUG() ? */
break;
}
- return ret;
+ return ret ?: nbytes;
}
static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
@@ -5964,9 +5965,10 @@
* Input must be in format '<event_fd> <control_fd> <args>'.
* Interpretation of args is defined by control file implementation.
*/
-static int memcg_write_event_control(struct cgroup_subsys_state *css,
- struct cftype *cft, char *buffer)
+static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
{
+ struct cgroup_subsys_state *css = of_css(of);
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_event *event;
struct cgroup_subsys_state *cfile_css;
@@ -5977,15 +5979,17 @@
char *endp;
int ret;
- efd = simple_strtoul(buffer, &endp, 10);
+ buf = strstrip(buf);
+
+ efd = simple_strtoul(buf, &endp, 10);
if (*endp != ' ')
return -EINVAL;
- buffer = endp + 1;
+ buf = endp + 1;
- cfd = simple_strtoul(buffer, &endp, 10);
+ cfd = simple_strtoul(buf, &endp, 10);
if ((*endp != ' ') && (*endp != '\0'))
return -EINVAL;
- buffer = endp + 1;
+ buf = endp + 1;
event = kzalloc(sizeof(*event), GFP_KERNEL);
if (!event)
@@ -6063,7 +6067,7 @@
goto out_put_cfile;
}
- ret = event->register_event(memcg, event->eventfd, buffer);
+ ret = event->register_event(memcg, event->eventfd, buf);
if (ret)
goto out_put_css;
@@ -6076,7 +6080,7 @@
fdput(cfile);
fdput(efile);
- return 0;
+ return nbytes;
out_put_css:
css_put(css);
@@ -6107,13 +6111,13 @@
{
.name = "limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
- .write_string = mem_cgroup_write,
+ .write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
.name = "soft_limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
- .write_string = mem_cgroup_write,
+ .write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
@@ -6138,7 +6142,7 @@
},
{
.name = "cgroup.event_control", /* XXX: for compat */
- .write_string = memcg_write_event_control,
+ .write = memcg_write_event_control,
.flags = CFTYPE_NO_PREFIX,
.mode = S_IWUGO,
},
@@ -6171,7 +6175,7 @@
{
.name = "kmem.limit_in_bytes",
.private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
- .write_string = mem_cgroup_write,
+ .write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{
@@ -6217,7 +6221,7 @@
{
.name = "memsw.limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
- .write_string = mem_cgroup_write,
+ .write = mem_cgroup_write,
.read_u64 = mem_cgroup_read_u64,
},
{