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

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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>
This commit is contained in:
Tejun Heo
2014-05-13 12:16:21 -04:00
parent b41686401e
commit 451af504df
11 changed files with 124 additions and 125 deletions
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17
mm/hugetlb_cgroup.c
View File

@@ -253,15 +253,16 @@ static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,
return res_counter_read_u64(&h_cg->hugepage[idx], name);
}
static int hugetlb_cgroup_write(struct cgroup_subsys_state *css,
struct cftype *cft, char *buffer)
static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
int idx, name, ret;
unsigned long long val;
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
idx = MEMFILE_IDX(cft->private);
name = MEMFILE_ATTR(cft->private);
buf = strstrip(buf);
idx = MEMFILE_IDX(of_cft(of)->private);
name = MEMFILE_ATTR(of_cft(of)->private);
switch (name) {
case RES_LIMIT:
@@ -271,7 +272,7 @@ static int hugetlb_cgroup_write(struct cgroup_subsys_state *css,
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;
ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
@@ -280,7 +281,7 @@ static int hugetlb_cgroup_write(struct cgroup_subsys_state *css,
ret = -EINVAL;
break;
}
return ret;
return ret ?: nbytes;
}
static int hugetlb_cgroup_reset(struct cgroup_subsys_state *css,
@@ -331,7 +332,7 @@ static void __init __hugetlb_cgroup_file_init(int idx)
snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
cft->read_u64 = hugetlb_cgroup_read_u64;
cft->write_string = hugetlb_cgroup_write;
cft->write = hugetlb_cgroup_write;
/* Add the usage file */
cft = &h->cgroup_files[1];