[PATCH] proc: comment what proc_fill_cache does

typedef struct dentry *instantiate_t(struct inode *, struct dentry *, struct task_struct *, void *);

/*

 * Fill a directory entry.

 *

 * If possible create the dcache entry and derive our inode number and

 * file type from dcache entry.

 *

 * Since all of the proc inode numbers are dynamically generated, the inode

 * numbers do not exist until the inode is cache.  This means creating the

 * the dcache entry in readdir is necessary to keep the inode numbers

 * reported by readdir in sync with the inode numbers reported

 * by stat.

 */

static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,

	char *name, int len,

	instantiate_t instantiate, struct task_struct *task, void *ptr)