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Commit 42d36115 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

[PATCH] uml: watchdog driver locking 



Replace BKL use with a spinlock.

Also fix the control so that open doesn't return holding a lock.

Signed-off-by: default avatarJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4ea21cd9

arch/um/drivers/harddog_kern.c

+15 −8
Original line number Diff line number Diff line
@@ -44,12 +44,13 @@ 
#include <linux/reboot.h>

#include <linux/smp_lock.h>

#include <linux/init.h>

#include <linux/spinlock.h>

#include <asm/uaccess.h>

#include "mconsole.h"



MODULE_LICENSE("GPL");



/* Locked by the BKL in harddog_open and harddog_release */

static DEFINE_SPINLOCK(lock);

static int timer_alive;

static int harddog_in_fd = -1;

static int harddog_out_fd = -1;
@@ -62,12 +63,12 @@ extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock); 


static int harddog_open(struct inode *inode, struct file *file)

{

	int err;

	int err = -EBUSY;

	char *sock = NULL;



	lock_kernel();

	spin_lock(&lock);

	if(timer_alive)

		return -EBUSY;

		goto err;

#ifdef CONFIG_HARDDOG_NOWAYOUT	 

	__module_get(THIS_MODULE);

#endif
@@ -76,11 +77,15 @@ static int harddog_open(struct inode *inode, struct file *file) 
	sock = mconsole_notify_socket();

#endif

	err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock);

	if(err) return(err);

	if(err)

		goto err;



	timer_alive = 1;

	unlock_kernel();

	spin_unlock(&lock);

	return nonseekable_open(inode, file);

err:

	spin_unlock(&lock);

	return err;

}



extern void stop_watchdog(int in_fd, int out_fd);
@@ -90,14 +95,16 @@ static int harddog_release(struct inode *inode, struct file *file) 
	/*

	 *	Shut off the timer.

	 */

	lock_kernel();



	spin_lock(&lock);



	stop_watchdog(harddog_in_fd, harddog_out_fd);

	harddog_in_fd = -1;

	harddog_out_fd = -1;



	timer_alive=0;

	unlock_kernel();

	spin_unlock(&lock);



	return 0;

}