diff options
author | Tejun Heo <tj@kernel.org> | 2013-12-05 12:28:04 -0500 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2013-12-05 12:28:04 -0500 |
commit | 7da112792753d71aed44b918395892a1fc53048a (patch) | |
tree | 7b370245a961024428a9247f8999f0f4b51c2c4f /kernel/cgroup.c | |
parent | 5d22444f427511fe7c4733b233680309af5b071c (diff) | |
download | linux-7da112792753d71aed44b918395892a1fc53048a.tar.bz2 |
cgroup: attach cgroup_open_file to all cgroup files
In preparation of conversion to kernfs, cgroup file handling is
updated so that it can be easily mapped to kernfs. This patch
attaches cgroup_open_file, which used to be attached to pidlist files,
to all cgroup files, introduces seq_css/cft() accessors to determine
the cgroup_subsys_state and cftype associated with a given cgroup
seq_file, exports them as public interface.
This doesn't cause any behavior changes but unifies cgroup file
handling across different file types and will help converting them to
kernfs seq_show() interface.
v2: Li pointed out that the original patch was using
single_open_size() incorrectly assuming that the size param is
private data size. Fix it by allocating @of separately and
passing it to single_open() and explicitly freeing it in the
release path. This isn't the prettiest but this path is gonna be
restructured by the following patches pretty soon.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r-- | kernel/cgroup.c | 50 |
1 files changed, 20 insertions, 30 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 17272893d3b8..036c05d8e572 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -41,7 +41,6 @@ #include <linux/rcupdate.h> #include <linux/sched.h> #include <linux/backing-dev.h> -#include <linux/seq_file.h> #include <linux/slab.h> #include <linux/magic.h> #include <linux/spinlock.h> @@ -130,19 +129,6 @@ static struct cgroupfs_root cgroup_dummy_root; /* dummy_top is a shorthand for the dummy hierarchy's top cgroup */ static struct cgroup * const cgroup_dummy_top = &cgroup_dummy_root.top_cgroup; -/* - * cgroupfs file entry, pointed to from leaf dentry->d_fsdata. - */ -struct cfent { - struct list_head node; - struct dentry *dentry; - struct cftype *type; - struct cgroup_subsys_state *css; - - /* file xattrs */ - struct simple_xattrs xattrs; -}; - /* The list of hierarchy roots */ static LIST_HEAD(cgroup_roots); @@ -2302,9 +2288,8 @@ out_free: static int cgroup_seqfile_show(struct seq_file *m, void *arg) { - struct cfent *cfe = m->private; - struct cftype *cft = cfe->type; - struct cgroup_subsys_state *css = cfe->css; + struct cftype *cft = seq_cft(m); + struct cgroup_subsys_state *css = seq_css(m); if (cft->read_seq_string) return cft->read_seq_string(css, cft, m); @@ -2353,10 +2338,20 @@ static int cgroup_file_open(struct inode *inode, struct file *file) WARN_ON_ONCE(cfe->css && cfe->css != css); cfe->css = css; - if (cft->open) + if (cft->open) { err = cft->open(inode, file); - else - err = single_open(file, cgroup_seqfile_show, cfe); + } else { + struct cgroup_open_file *of; + + err = -ENOMEM; + of = kzalloc(sizeof(*of), GFP_KERNEL); + if (of) { + of->cfe = cfe; + err = single_open(file, cgroup_seqfile_show, of); + if (err) + kfree(of); + } + } if (css->ss && err) css_put(css); @@ -2370,6 +2365,7 @@ static int cgroup_file_release(struct inode *inode, struct file *file) if (css->ss) css_put(css); + kfree(((struct seq_file *)file->private_data)->private); return single_release(inode, file); } @@ -3368,12 +3364,6 @@ struct cgroup_pidlist { struct delayed_work destroy_dwork; }; -/* seq_file->private points to the following */ -struct cgroup_open_file { - struct cfent *cfe; - void *priv; -}; - /* * The following two functions "fix" the issue where there are more pids * than kmalloc will give memory for; in such cases, we use vmalloc/vfree. @@ -3689,9 +3679,9 @@ static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos) * next pid to display, if any */ struct cgroup_open_file *of = s->private; - struct cgroup *cgrp = of->cfe->css->cgroup; + struct cgroup *cgrp = seq_css(s)->cgroup; struct cgroup_pidlist *l; - enum cgroup_filetype type = of->cfe->type->private; + enum cgroup_filetype type = seq_cft(s)->private; int index = 0, pid = *pos; int *iter, ret; @@ -3749,7 +3739,7 @@ static void cgroup_pidlist_stop(struct seq_file *s, void *v) if (l) mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork, CGROUP_PIDLIST_DESTROY_DELAY); - mutex_unlock(&of->cfe->css->cgroup->pidlist_mutex); + mutex_unlock(&seq_css(s)->cgroup->pidlist_mutex); } static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos) @@ -3766,7 +3756,7 @@ static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos) if (p >= end) { return NULL; } else { - *pos = cgroup_pid_fry(of->cfe->css->cgroup, *p); + *pos = cgroup_pid_fry(seq_css(s)->cgroup, *p); return p; } } |