Commit 60f126d9 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

sysctl: Comments to make the code clearer. 



Document get_subdir and that find_subdir alwasy takes a reference.

Suggested-by: default avatarLucian Adrian Grijincu <lucian.grijincu@gmail.com>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent 0eb97f38

fs/proc/proc_sysctl.c

+16 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ static int namecmp(const char *name1, int len1, const char *name2, int len2) 
	return cmp;

}



/* Called under sysctl_lock */

static struct ctl_table *find_entry(struct ctl_table_header **phead,

	struct ctl_dir *dir, const char *name, int namelen)

{
@@ -864,6 +865,18 @@ static struct ctl_dir *new_dir(struct ctl_table_set *set, 
	return new;

}



/**

 * get_subdir - find or create a subdir with the specified name.

 * @dir:  Directory to create the subdirectory in

 * @name: The name of the subdirectory to find or create

 * @namelen: The length of name

 *

 * Takes a directory with an elevated reference count so we know that

 * if we drop the lock the directory will not go away.  Upon success

 * the reference is moved from @dir to the returned subdirectory.

 * Upon error an error code is returned and the reference on @dir is

 * simply dropped.

 */

static struct ctl_dir *get_subdir(struct ctl_dir *dir,

				  const char *name, int namelen)

{
@@ -885,12 +898,14 @@ static struct ctl_dir *get_subdir(struct ctl_dir *dir, 
	if (!new)

		goto failed;



	/* Was the subdir added while we dropped the lock? */

	subdir = find_subdir(dir, name, namelen);

	if (!IS_ERR(subdir))

		goto found;

	if (PTR_ERR(subdir) != -ENOENT)

		goto failed;



	/* Nope.  Use the our freshly made directory entry. */

	err = insert_header(dir, &new->header);

	subdir = ERR_PTR(err);

	if (err)
@@ -1190,6 +1205,7 @@ struct ctl_table_header *__register_sysctl_table( 


	spin_lock(&sysctl_lock);

	dir = &set->dir;

	/* Reference moved down the diretory tree get_subdir */

	dir->header.nreg++;

	spin_unlock(&sysctl_lock);