In preparation of conversion to kernfs, cgroup file handling is
updated so that it can be easily mapped to kernfs. This patch renames
cgroup_pidlist_open_file to cgroup_open_file and updates it so that it
only contains a field to identify the specific file, ->cfe, and an
opaque ->priv pointer. When cgroup is converted to kernfs, this will
be replaced by kernfs_open_file which contains about the same
information.
As whether the file is "cgroup.procs" or "tasks" should now be
determined from cgroup_open_file->cfe, the cftype->private for the two
files now carry the file type and cgroup_pidlist_start() reads the
type through cfe->type->private. This makes the distinction between
cgroup_tasks_open() and cgroup_procs_open() unnecessary.
cgroup_pidlist_open() is now directly used as the open method.
This patch doesn't make any behavior changes.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
kernel/cgroup.c | 66 ++++++++++++++++++++++++++-------------------------------
1 file changed, 30 insertions(+), 36 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 7048e7f..bdb8e8d 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3369,10 +3369,9 @@ struct cgroup_pidlist {
};
/* seq_file->private points to the following */
-struct cgroup_pidlist_open_file {
- enum cgroup_filetype type;
- struct cgroup *cgrp;
- struct cgroup_pidlist *pidlist;
+struct cgroup_open_file {
+ struct cfent *cfe;
+ void *priv;
};
/*
@@ -3689,33 +3688,35 @@ static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos)
* after a seek to the start). Use a binary-search to find the
* next pid to display, if any
*/
- struct cgroup_pidlist_open_file *of = s->private;
- struct cgroup *cgrp = of->cgrp;
+ struct cgroup_open_file *of = s->private;
+ struct cgroup *cgrp = of->cfe->css->cgroup;
struct cgroup_pidlist *l;
+ enum cgroup_filetype type = of->cfe->type->private;
int index = 0, pid = *pos;
int *iter, ret;
mutex_lock(&cgrp->pidlist_mutex);
/*
- * !NULL @of->pidlist indicates that this isn't the first start()
+ * !NULL @of->priv indicates that this isn't the first start()
* after open. If the matching pidlist is around, we can use that.
- * Look for it. Note that @of->pidlist can't be used directly. It
+ * Look for it. Note that @of->priv can't be used directly. It
* could already have been destroyed.
*/
- if (of->pidlist)
- of->pidlist = cgroup_pidlist_find(cgrp, of->type);
+ if (of->priv)
+ of->priv = cgroup_pidlist_find(cgrp, type);
/*
* Either this is the first start() after open or the matching
* pidlist has been destroyed inbetween. Create a new one.
*/
- if (!of->pidlist) {
- ret = pidlist_array_load(of->cgrp, of->type, &of->pidlist);
+ if (!of->priv) {
+ ret = pidlist_array_load(cgrp, type,
+ (struct cgroup_pidlist **)&of->priv);
if (ret)
return ERR_PTR(ret);
}
- l = of->pidlist;
+ l = of->priv;
if (pid) {
int end = l->length;
@@ -3742,19 +3743,19 @@ static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos)
static void cgroup_pidlist_stop(struct seq_file *s, void *v)
{
- struct cgroup_pidlist_open_file *of = s->private;
+ struct cgroup_open_file *of = s->private;
+ struct cgroup_pidlist *l = of->priv;
- if (of->pidlist)
- mod_delayed_work(cgroup_pidlist_destroy_wq,
- &of->pidlist->destroy_dwork,
+ if (l)
+ mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork,
CGROUP_PIDLIST_DESTROY_DELAY);
- mutex_unlock(&of->cgrp->pidlist_mutex);
+ mutex_unlock(&of->cfe->css->cgroup->pidlist_mutex);
}
static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos)
{
- struct cgroup_pidlist_open_file *of = s->private;
- struct cgroup_pidlist *l = of->pidlist;
+ struct cgroup_open_file *of = s->private;
+ struct cgroup_pidlist *l = of->priv;
pid_t *p = v;
pid_t *end = l->list + l->length;
/*
@@ -3765,7 +3766,7 @@ 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->cgrp, *p);
+ *pos = cgroup_pid_fry(of->cfe->css->cgroup, *p);
return p;
}
}
@@ -3799,10 +3800,10 @@ static const struct file_operations cgroup_pidlist_operations = {
* in the cgroup.
*/
/* helper function for the two below it */
-static int cgroup_pidlist_open(struct file *file, enum cgroup_filetype type)
+static int cgroup_pidlist_open(struct inode *unused, struct file *file)
{
- struct cgroup *cgrp = __d_cgrp(file->f_dentry->d_parent);
- struct cgroup_pidlist_open_file *of;
+ struct cfent *cfe = __d_cfe(file->f_dentry);
+ struct cgroup_open_file *of;
int retval;
/* configure file information */
@@ -3814,18 +3815,9 @@ static int cgroup_pidlist_open(struct file *file, enum cgroup_filetype type)
return retval;
of = ((struct seq_file *)file->private_data)->private;
- of->type = type;
- of->cgrp = cgrp;
+ of->cfe = cfe;
return 0;
}
-static int cgroup_tasks_open(struct inode *unused, struct file *file)
-{
- return cgroup_pidlist_open(file, CGROUP_FILE_TASKS);
-}
-static int cgroup_procs_open(struct inode *unused, struct file *file)
-{
- return cgroup_pidlist_open(file, CGROUP_FILE_PROCS);
-}
static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css,
struct cftype *cft)
@@ -3880,7 +3872,8 @@ static int cgroup_clone_children_write(struct cgroup_subsys_state *css,
static struct cftype cgroup_base_files[] = {
{
.name = "cgroup.procs",
- .open = cgroup_procs_open,
+ .open = cgroup_pidlist_open,
+ .private = CGROUP_FILE_PROCS,
.write_u64 = cgroup_procs_write,
.mode = S_IRUGO | S_IWUSR,
},
@@ -3904,7 +3897,8 @@ static struct cftype cgroup_base_files[] = {
{
.name = "tasks",
.flags = CFTYPE_INSANE, /* use "procs" instead */
- .open = cgroup_tasks_open,
+ .open = cgroup_pidlist_open,
+ .private = CGROUP_FILE_TASKS,
.write_u64 = cgroup_tasks_write,
.mode = S_IRUGO | S_IWUSR,
},
--
1.8.4.2
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