linux-imx

/*

 *  linux/fs/file_table.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *  Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)

 */

​

#include <linux/string.h>

#include <linux/slab.h>

#include <linux/file.h>

#include <linux/fdtable.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/fs.h>

#include <linux/security.h>

#include <linux/cred.h>

#include <linux/eventpoll.h>

#include <linux/rcupdate.h>

#include <linux/mount.h>

#include <linux/capability.h>

#include <linux/cdev.h>

#include <linux/fsnotify.h>

#include <linux/sysctl.h>

#include <linux/percpu_counter.h>

#include <linux/percpu.h>

#include <linux/task_work.h>

#include <linux/ima.h>

#include <linux/swap.h>

​

#include <linux/atomic.h>

​

#include "internal.h"

​

/* sysctl tunables... */

struct files_stat_struct files_stat = {

    .max_files = NR_FILE

};

​

/* SLAB cache for file structures */

static struct kmem_cache *filp_cachep __read_mostly;

​

static struct percpu_counter nr_files __cacheline_aligned_in_smp;

​

static void file_free_rcu(struct rcu_head *head)

{

    struct file *f = container_of(head, struct file, f_u.fu_rcuhead);

​

    put_cred(f->f_cred);

    kmem_cache_free(filp_cachep, f);

}

​

static inline void file_free(struct file *f)

{

    security_file_free(f);

    if (!(f->f_mode & FMODE_NOACCOUNT))

        percpu_counter_dec(&nr_files);

    call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);

}

​

/*

 * Return the total number of open files in the system

 */

static long get_nr_files(void)

{

    return percpu_counter_read_positive(&nr_files);

}

​

/*

 * Return the maximum number of open files in the system

 */

unsigned long get_max_files(void)

{

    return files_stat.max_files;

}

EXPORT_SYMBOL_GPL(get_max_files);

​

/*

 * Handle nr_files sysctl

 */

#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS)

int proc_nr_files(struct ctl_table *table, int write,

                     void __user *buffer, size_t *lenp, loff_t *ppos)

{

    files_stat.nr_files = get_nr_files();

    return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);

}

#else

int proc_nr_files(struct ctl_table *table, int write,

                     void __user *buffer, size_t *lenp, loff_t *ppos)

{

    return -ENOSYS;

}