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Commit 05d86412 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86: Remove BKL from apm_32 



The lock/unlock kernel pair in do_open() got there with the BKL push
down and protects nothing. Remove it.

Replace the lock/unlock kernel in the ioctl code with a mutex to
protect standbys_pending and suspends_pending.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20091010153349.365236337@linutronix.de>
parent ac06ea2c

arch/x86/kernel/apm_32.c

+6 −8
Original line number Diff line number Diff line
@@ -204,7 +204,6 @@ 
#include <linux/module.h>



#include <linux/poll.h>

#include <linux/smp_lock.h>

#include <linux/types.h>

#include <linux/stddef.h>

#include <linux/timer.h>
@@ -403,6 +402,7 @@ static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue); 
static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);

static struct apm_user *user_list;

static DEFINE_SPINLOCK(user_list_lock);

static DEFINE_MUTEX(apm_mutex);



/*

 * Set up a segment that references the real mode segment 0x40
@@ -1531,7 +1531,7 @@ static long do_ioctl(struct file *filp, u_int cmd, u_long arg) 
		return -EPERM;

	switch (cmd) {

	case APM_IOC_STANDBY:

		lock_kernel();

		mutex_lock(&apm_mutex);

		if (as->standbys_read > 0) {

			as->standbys_read--;

			as->standbys_pending--;
@@ -1540,10 +1540,10 @@ static long do_ioctl(struct file *filp, u_int cmd, u_long arg) 
			queue_event(APM_USER_STANDBY, as);

		if (standbys_pending <= 0)

			standby();

		unlock_kernel();

		mutex_unlock(&apm_mutex);

		break;

	case APM_IOC_SUSPEND:

		lock_kernel();

		mutex_lock(&apm_mutex);

		if (as->suspends_read > 0) {

			as->suspends_read--;

			as->suspends_pending--;
@@ -1552,13 +1552,14 @@ static long do_ioctl(struct file *filp, u_int cmd, u_long arg) 
			queue_event(APM_USER_SUSPEND, as);

		if (suspends_pending <= 0) {

			ret = suspend(1);

			mutex_unlock(&apm_mutex);

		} else {

			as->suspend_wait = 1;

			mutex_unlock(&apm_mutex);

			wait_event_interruptible(apm_suspend_waitqueue,

					as->suspend_wait == 0);

			ret = as->suspend_result;

		}

		unlock_kernel();

		return ret;

	default:

		return -ENOTTY;
@@ -1608,12 +1609,10 @@ static int do_open(struct inode *inode, struct file *filp) 
{

	struct apm_user *as;



	lock_kernel();

	as = kmalloc(sizeof(*as), GFP_KERNEL);

	if (as == NULL) {

		printk(KERN_ERR "apm: cannot allocate struct of size %d bytes\n",

		       sizeof(*as));

		       unlock_kernel();

		return -ENOMEM;

	}

	as->magic = APM_BIOS_MAGIC;
@@ -1635,7 +1634,6 @@ static int do_open(struct inode *inode, struct file *filp) 
	user_list = as;

	spin_unlock(&user_list_lock);

	filp->private_data = as;

	unlock_kernel();

	return 0;

}