Revision de5604231ce4bc8db1bc1dcd27d8540cbedf1518 authored by Nick Piggin on 01 February 2010, 11:24:18 UTC, committed by Linus Torvalds on 02 February 2010, 20:50:47 UTC
RCU list walking of the per-cpu vmap cache was broken. It did not use RCU primitives, and also the union of free_list and rcu_head is obviously wrong (because free_list is indeed the list we are RCU walking). While we are there, remove a couple of unused fields from an earlier iteration. These APIs aren't actually used anywhere, because of problems with the XFS conversion. Christoph has now verified that the problems are solved with these patches. Also it is an exported interface, so I think it will be good to be merged now (and Christoph wants to get the XFS changes into their local tree). Cc: stable@kernel.org Cc: linux-mm@kvack.org Tested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Nick Piggin <npiggin@suse.de> -- Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 489b24f
phonedev.c
/*
* Telephony registration for Linux
*
* (c) Copyright 1999 Red Hat Software Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Author: Alan Cox, <alan@lxorguk.ukuu.org.uk>
*
* Fixes: Mar 01 2000 Thomas Sparr, <thomas.l.sparr@telia.com>
* phone_register_device now works with unit!=PHONE_UNIT_ANY
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/phonedev.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/kmod.h>
#include <linux/sem.h>
#include <linux/mutex.h>
#define PHONE_NUM_DEVICES 256
/*
* Active devices
*/
static struct phone_device *phone_device[PHONE_NUM_DEVICES];
static DEFINE_MUTEX(phone_lock);
/*
* Open a phone device.
*/
static int phone_open(struct inode *inode, struct file *file)
{
unsigned int minor = iminor(inode);
int err = 0;
struct phone_device *p;
const struct file_operations *old_fops, *new_fops = NULL;
if (minor >= PHONE_NUM_DEVICES)
return -ENODEV;
mutex_lock(&phone_lock);
p = phone_device[minor];
if (p)
new_fops = fops_get(p->f_op);
if (!new_fops) {
mutex_unlock(&phone_lock);
request_module("char-major-%d-%d", PHONE_MAJOR, minor);
mutex_lock(&phone_lock);
p = phone_device[minor];
if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL)
{
err=-ENODEV;
goto end;
}
}
old_fops = file->f_op;
file->f_op = new_fops;
if (p->open)
err = p->open(p, file); /* Tell the device it is open */
if (err) {
fops_put(file->f_op);
file->f_op = fops_get(old_fops);
}
fops_put(old_fops);
end:
mutex_unlock(&phone_lock);
return err;
}
/*
* Telephony For Linux device drivers request registration here.
*/
int phone_register_device(struct phone_device *p, int unit)
{
int base;
int end;
int i;
base = 0;
end = PHONE_NUM_DEVICES - 1;
if (unit != PHONE_UNIT_ANY) {
base = unit;
end = unit + 1; /* enter the loop at least one time */
}
mutex_lock(&phone_lock);
for (i = base; i < end; i++) {
if (phone_device[i] == NULL) {
phone_device[i] = p;
p->minor = i;
mutex_unlock(&phone_lock);
return 0;
}
}
mutex_unlock(&phone_lock);
return -ENFILE;
}
/*
* Unregister an unused Telephony for linux device
*/
void phone_unregister_device(struct phone_device *pfd)
{
mutex_lock(&phone_lock);
if (likely(phone_device[pfd->minor] == pfd))
phone_device[pfd->minor] = NULL;
mutex_unlock(&phone_lock);
}
static const struct file_operations phone_fops =
{
.owner = THIS_MODULE,
.open = phone_open,
};
/*
* Board init functions
*/
/*
* Initialise Telephony for linux
*/
static int __init telephony_init(void)
{
printk(KERN_INFO "Linux telephony interface: v1.00\n");
if (register_chrdev(PHONE_MAJOR, "telephony", &phone_fops)) {
printk("phonedev: unable to get major %d\n", PHONE_MAJOR);
return -EIO;
}
return 0;
}
static void __exit telephony_exit(void)
{
unregister_chrdev(PHONE_MAJOR, "telephony");
}
module_init(telephony_init);
module_exit(telephony_exit);
MODULE_LICENSE("GPL");
EXPORT_SYMBOL(phone_register_device);
EXPORT_SYMBOL(phone_unregister_device);
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