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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
Download Patch File Download Diff File Expand all files Collapse all files

12
net/core/netprio_cgroup.c
View File

@@ -185,15 +185,15 @@ static int read_priomap(struct seq_file *sf, void *v)
return 0;
}
static int write_priomap(struct cgroup_subsys_state *css, struct cftype *cft,
char *buffer)
static ssize_t write_priomap(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
char devname[IFNAMSIZ + 1];
struct net_device *dev;
u32 prio;
int ret;
if (sscanf(buffer, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2)
if (sscanf(buf, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2)
return -EINVAL;
dev = dev_get_by_name(&init_net, devname);
@@ -202,11 +202,11 @@ static int write_priomap(struct cgroup_subsys_state *css, struct cftype *cft,
rtnl_lock();
ret = netprio_set_prio(css, dev, prio);
ret = netprio_set_prio(of_css(of), dev, prio);
rtnl_unlock();
dev_put(dev);
return ret;
return ret ?: nbytes;
}
static int update_netprio(const void *v, struct file *file, unsigned n)
@@ -239,7 +239,7 @@ static struct cftype ss_files[] = {
{
.name = "ifpriomap",
.seq_show = read_priomap,
.write_string = write_priomap,
.write = write_priomap,
},
{ } /* terminate */
};